The optimal criteria for lateral lymph node dissection (LLND) in rectal cancer following neoadjuvant therapy remain undefined. This systematic review and meta-analysis evaluated the diagnostic accuracy of lateral lymph node metastasis (LLNM) to refine criteria for selective LLND.

A systematic search of PubMed, Embase, and the Cochrane Library (10 August 2024) identified studies assessing magnetic resonance imaging (MRI)-based LLNM detection in patients with rectal cancer who underwent neoadjuvant therapy and radical surgery. Studies reporting MRI-based LLNM assessments with pathological confirmation were included. Non-English studies, reviews, case reports, and those lacking lymph node size data were excluded. The risk of bias was assessed using QUADAS-2. Pooled sensitivity, specificity, and diagnostic odds ratios were estimated using hierarchical summary receiver operating characteristic curve (HSROC) analysis.

Eleven studies met the inclusion criteria. All used MRI-based size assessments. The pooled sensitivity and specificity were 0.776 (95% CI: 0.639-0.872) and 0.694 (95% CI: 0.541-0.813), respectively, with an HSROC area under the curve (AUC) of 0.801.

MRI is the most widely used modality for diagnosing LLNM in rectal cancer patients who have undergone neoadjuvant therapy, with size criteria being the most commonly applied.

PROSPERO (CRD42024578499).

Rectal cancer is a leading cause of cancer-related mortality worldwide. The recurrence of locally advanced rectal cancer (LARC), particularly in cases involving lymph node-positive tumours, remains a critical challenge in rectal cancer management. In this study, a therapeutic strategy, radiation-activated photodynamic therapy (RA-PDT), for the treatment of LARC with lymph node-positive tumours was developed and evaluated.

RA-PDT was achieved by using a lipid-polymer hybrid nanoplatform loaded with verteporfin (VP) and functionalised with folic acid (FA) as a targeting molecule. Upon receiving a single 4 Gy fraction of radiation, VP was effectively activated, generating sufficient reactive oxygen species (ROS) to induce cancer cell death-however surrounding tissue was less affected and was spared. The efficacy of this strategy was assessed through in vitro cytotoxicity studies in HCT116 cells, as well as in orthotopic and subcutaneous mouse models. In vivo lymph node tumour progression was also evaluated.

RA-PDT effectively generated ROS following 4 Gy irradiation and exhibited significant cytotoxicity in HCT116 cells. In vivo, this strategy largely inhibited primary tumour growth in both orthotopic and subcutaneous mouse models while also suppressing lymph node tumour progression. Surrounding tissues were minimally affected, highlighting the precision and safety of this approach.

RA-PDT demonstrates potential as a safe therapeutic strategy for LARC, paving the way for its clinical translation.

This study was supported by the Australian National Health and Medical Research Council (GNT1181889), fellowship award (2019/CDF1013) from Cancer Institute NSW, Australia, the Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CE140100003), UNSW SHARP funding, project grant from National Foundation for Medical Research and Innovation, Australia, International Research Training Program Scholarship (IRTP) from Australian Government, PhD Research Scholar Award from Sydney Vital Translational Cancer Research, and Translational Cancer Research Network PhD Scholarship Top-up award.

MRI has relatively low sensitivity and specificity in detecting lymph node metastases. This study aimed to develop and validate an MRI radiomics-based model for predicting lateral pelvic lymph node (LPLN) metastasis in rectal cancer patients who underwent LPLN dissection, and to compare its performance with that of radiologists. This multicenter retrospective study included 336 rectal cancer patients (199 men; mean age, 58.9 years ± 11.1 [standard deviation]) who underwent LPLN dissection. Patients were divided into development (n = 190) and validation (n = 146) cohorts. Radiomics features were extracted from MR images, and the Least Absolute Shrinkage and Selection Operator regression was used to construct radiomics and clinical-radiomics models. Model performance was compared with radiologists using receiver operating characteristic (ROC) analysis. Malignant LPLN was diagnosed in 32.4% of the development cohort (65/190) and 32.9% of the validation cohort (48/146) (P = 0.798). Seven radiomics features and two clinical features were selected. The radiomics and clinical-radiomics models demonstrated area under the curves (AUCs) of 0.819 and 0.830 in the development cohort and 0.821 and 0.829 in the validation cohort, respectively. The optimal cut-off (- 0.47) yielded sensitivities of 72.3% and 45.8% and specificities of 82.4% and 87.8% in the development and validation cohorts, respectively. Decision curve analysis indicated no additional net benefit from the clinical-radiomics model compared to the radiomics-only model. Radiologists' AUCs were significantly lower than that of the radiomics model (0.842) and improved with radiomics probability scores (0.734 vs. 0.801; 0.668 vs. 0.791). The MRI-based radiomics model significantly improves the prediction of LPLN metastasis in rectal cancer, outperforming conventional criteria used by radiologists.Trial registration: Retrospectively registered.

Complete resection of advanced rectal cancer is challenging, with local recurrence rates ranging from 4% to 12%. Local recurrence is often categorized as central, anastomotic, or lateral, with lateral lymph node (LLN) metastasis being the primary driver of lateral recurrence. Although preoperative radiotherapy effectively manages nonlateral recurrences, it is less effective for lateral recurrences, and LLN dissection significantly reduces lateral recurrence rates. This study aimed to clarify the clinicopathological characteristics associated with lateral and nonlateral recurrences.

We retrospectively analyzed 232 patients (156 males and 76 females; median age, 64 years) who underwent preoperative radiotherapy followed by curative-intent surgery for clinical T3/4 rectal adenocarcinoma located below the peritoneal reflection between April 2010 and December 2017. In total, 40% of the patients underwent LLN dissection. Univariate and multivariate analyses of clinicopathological data were performed to identify the independent risk factors for lateral and nonlateral recurrences.

Local recurrence occurred in 19 (8%) patients: 7 had lateral recurrence, 13 had nonlateral recurrence, and 1 had both. Multivariate analysis identified mesorectal lymph node metastasis as a significant risk factor for lateral recurrence, whereas positive circumferential resection margin was a significant risk factor for nonlateral recurrence.

The identification of different risk factors for lateral and nonlateral recurrence suggests that lateral recurrence is more strongly associated with lymphatic permeation than nonlateral recurrence. These findings highlight the importance of LLN dissection in minimizing the risk of lateral recurrence.

There is a lack of consensus regarding treating involved lateral pelvic lymph nodes in rectal cancer.

This study aimed to evaluate the clinical and MRI-based factors associated with pathological lateral pelvic lymph node metastasis in patients undergoing total neoadjuvant therapy and lateral pelvic lymph node dissection.

This is a retrospective study.

This study was conducted at a single comprehensive cancer center.

A total of 107 patients with advanced low rectal cancer with pretreatment enlarged lateral pelvic lymph nodes (≥7 mm in long axis) undergoing total neoadjuvant therapy with long-course chemoradiotherapy, followed by total mesorectal excision and lateral pelvic lymph node dissection, were enrolled.

Pathological lateral pelvic lymph node metastasis and survival.

Among 107 patients, short-axis lateral node diameter at baseline was <7 mm in 48 patients and ≥7 mm in 59 patients. The ≥7 mm group showed significantly higher rates of pathological lateral pelvic lymph node metastasis (44.1% vs 2.1%; p < 0.0001). In this group, pathological lateral pelvic lymph node metastasis was independently associated with pretreatment malignant features and posttreatment short-axis diameter ≥4 mm. Five-year relapse-free survival was significantly lower in patients with posttreatment lateral node diameter ≥4 mm than those with <4 mm (71.1% vs 86.2%, p = 0.0364). Patients with pathological lateral pelvic lymph node metastasis had significantly lower overall survival, relapse-free survival, and local recurrence-free survival rates.

Selection bias exists in a retrospective analysis.

Pathological lateral pelvic lymph node metastasis is rare in patients with pretreatment short-axis diameter <7 mm. In patients with pretreatment short-axis diameter ≥7 mm, pretreatment malignant features and posttreatment short-axis diameter are both associated with pathological lateral pelvic lymph node metastasis. These factors should be considered when deciding whether to proceed with lateral pelvic lymph node dissection after total neoadjuvant therapy. See Video Abstract.

ANTECEDENTES:No existe consenso sobre el tratamiento de los ganglios linfáticos pélvicos laterales afectados en el cáncer rectal.OBJETIVO:Este estudio tuvo como objetivo evaluar los factores clínicos y basados en imágenes de resonancia magnética asociados con la metástasis patológica de los ganglios linfáticos pélvicos laterales en pacientes sometidos a terapia neoadyuvante total y disección lateral de ganglios linfáticos pélvicos.DISEO:Este es un estudio retrospectivo.EORNO CLINICO:Este estudio se llevó a cabo en un solo centro oncológico integral.PACIENTES:Se inscribieron 107 pacientes con cáncer rectal bajo avanzado con ganglios linfáticos pélvicos laterales agrandados antes del tratamiento (≥7 mm en el eje largo) sometidos a terapia neoadyuvante total con quimiorradioterapia de larga duración, seguida de escisión mesorrectal total y disección de ganglios linfáticos pélvicos laterales.PRINCIPALES MEDIDAS DE RESULTADOS:Metástasis patológica de ganglios linfáticos pélvicos laterales y supervivencia.RESULTADOS:Entre 107 pacientes, 48 tenían un diámetro ganglionar lateral en el eje corto <7 mm al inicio, mientras que 59 tenían ≥7 mm. El grupo de ≥7 mm mostró tasas significativamente más altas de metástasis patológica de los ganglios linfáticos pélvicos laterales (44,1% vs 2,1%; p < 0,0001). En este grupo, la metástasis patológica de los ganglios linfáticos pélvicos laterales se asoció de forma independiente con características malignas previas al tratamiento y un diámetro ganglionar lateral posterior al tratamiento ≥4 mm. La supervivencia sin recidiva a los cinco años fue significativamente menor en pacientes con un diámetro ganglionar lateral posterior al tratamiento ≥4 mm que en aquellos con un diámetro <4 mm (71,1% vs 86,2%, p = 0,0364). Los pacientes con la metástasis patológica de los ganglios linfáticos pélvicos laterales tuvieron tasas de supervivencia global, supervivencia sin recidiva y supervivencia sin recurrencia local significativamente más bajas.LIMITACIONES:Existe sesgo de selección en un análisis retrospectivo.CONCLUSIONES:La metástasis patológica de los ganglios linfáticos pélvicos laterales es poco frecuente en pacientes con un diámetro del eje corto previo al tratamiento <7 mm. En pacientes con un diámetro del eje corto previo al tratamiento ≥7 mm, las características malignas previas al tratamiento y el diámetro del eje corto posterior al tratamiento se asocian con metástasis patológica de los ganglios linfáticos pélvicos laterales. Estos factores deben tenerse en cuenta al decidir si se debe proceder a la disección de los ganglios linfáticos pélvicos laterales después de la terapia neoadyuvante total. (Traducción- Dr. Francisco M. Abarca-Rendon).

To develop scoring systems to predict the need for selective lateral lymph node dissection (LLND) alongside total mesorectal excision (TME) in patients with locally advanced low rectal cancer after neoadjuvant chemoradiotherapy (nCRT), focusing on lateral local recurrence (LLR) and lateral lymph node (LLN) metastasis.

This retrospective study included 607 patients with mrT3/T4 rectal cancer located within 8 cm of the anal verge who underwent nCRT and TME. A development group was used to develop a scoring system predicting the necessity of LLND using logistic regression analysis, incorporating primary tumor and LLN features observed on rectal MRI. External validation was performed in an independent group of 144 patients. We also analyzed risk factors for recurrence and residual LLNs after LLND.

Model 1 included pretreatment LLN size and extramural venous invasion (EMVI). Model 2 incorporated pretreatment internal iliac and obturator lymph node sizes, EMVI, and nonresponsive LLN on restaging MRI. Model 3 focused solely on nonresponsive LLN on restaging MRI. In the development group, Models 1 and 2 exhibited better performance (area under the curve (AUC) = 0.92 and 0.90, respectively) than Model 3 (AUC = 0.79), consistent with the validation group. Among patients who underwent LLND, the distal internal iliac compartment had more residual lymph nodes than other compartments (p = 0.02).

Scoring systems utilizing LLN features and EMVI on MRI might aid in decision-making for selective LLND following nCRT in locally advanced low rectal cancer.

Question The criteria for when additional lateral lymph node dissection (LLND) may benefit in locally advanced low rectal cancer have not yet been definitively established. Findings Scoring systems (Model 1, 2) based on preoperative MRI utilize lateral lymph node (LLN) size and extramural venous invasion to predict the necessity of LLND. Clinical relevance The selective LLND along with total mesorectal excision aids in managing LLN metastasis and lateral local recurrence in locally advanced low rectal cancer after neoadjuvant chemoradiotherapy. The imaging-based scoring systems may guide clinical decision-making for selective LLND.

Metastatic lateral pelvic lymph node (LPN) in rectal cancer has a significant clinical impact on the prognosis and treatment strategies. But there are still debates regarding prediction of lateral pelvic lymph node metastasis and its oncological impact. This review explores the evidence for predicting lateral pelvic lymph node metastasis and survival in locally advanced rectal cancer. Until now many studies have reported that magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) are considered as essential tools for predicting metastatic LPN, with MRI-based size criteria, particularly the short-axis diameter of LPN. But several studies have reported that the addition of tumor location or artificial intelligence (AI) can further enhance diagnostic accuracy. Western practices focus more on neoadjuvant chemoradiation (nCRT), while Eastern countries focus more on lateral pelvic lymph node dissection (LPND). LPND has been shown to reduce lateral local recurrence (LLR) rates compared to total mesorectal excision (TME) alone, particularly in patients with enlarged LPNs, but its impact on overall survival is uncertain. The decision to perform LPND should be individualized according to LPN size and response to nCRT; and through selective LPND based on those criteria, patients could achieve a balance between the benefit of local control and the risk of surgical complications from LPND, such as sexual and urinary dysfunction.

Preoperative chemoradiotherapy combined with total mesorectal excision (TME) is a standard treatment for locally advanced rectal cancer (LARC). However, lateral pelvic lymph nodes (LPLNs) are often inadequately treated with standard regimens. This study examines the treatment and postoperative outcomes in LARC patients receiving a simultaneous integrated boost (SIB) for LPLNs during long-course chemoradiotherapy.

This retrospective study included high-risk LARC patients (UICC, "Union Internationale Contre le Cancer", stage III) treated with preoperative chemoradiotherapy and SIB to LPLNs. Radiotherapy was delivered to the primary tumor and elective volumes with 50.4 Gy in 28 fractions, and an SIB with a median dose of 60.2 Gy was administered to clinically positive LPLNs. TME quality and postoperative complications were assessed using MERCURY and Clavien-Dindo, respectively. Time-to-event data were analyzed according to Kaplan-Meier.

Between 2019 and 2023, 27 patients with high-risk LARC and LPLN metastases were treated with chemoradiotherapy. After a median follow-up of 19 months, 2‑year overall survival was 80%, disease-free survival 80%, and local control of dose-escalated lymph nodes 100%. Three patients were managed nonoperatively after a clinical complete response on endoscopy and imaging. Of the 22 patients who had surgery, only one had complications higher than Clavien-Dindo grade I; TME was graded as MERCURY I in 73%.

The SIB approach for LPLNs in LARC is feasible, does not increase postoperative morbidity, and achieves excellent local control. This study supports the consideration of dose-escalated radiotherapy for LPLNs to address high local recurrence risks.

Lateral pelvic node dissection (LPLND) is indicated in the surgical management of clinically significant pelvic lymphadenopathy associated with rectal malignancies. However, procedure-related morbidity, including the incidence and predisposing factors for lymphoceles arising in this setting have not been adequately evaluated.

This retrospective single-institution study included 183 patients with nonmetastatic, lateral node-positive rectal cancer undergoing total mesorectal excision with LPLND between June 2014 and May 2023 to determine the incidence and severity of postoperative complications using the Clavien-Dindo system, with logistic regression performed to model a relationship between lymphocele-development and potentially-predictive variables.

In this cohort, mean age was 45.3 ± 12.81 years, 62.8% were male, and 27.9% had body mass index ≥ 25 kg/m2. Median tumor-distance from the verge was 3.0 (interquartile range [IQR] 1.0-5.0) cm. Following radiotherapy in 86.9%, all patients underwent surgery: 30.1% had open resection and 26.2% had bilateral LPLND. Median nodal-yield was 6 (IQR 4-8) per side. Postoperatively, 45.3% developed complications, with 18% considered clinically significant. Lymphoceles, detected in 21.3%, comprised the single-most common sequelae following LPLND, 46.2% arising within 30 days of surgery and 33.3% requiring intervention. On multivariate analyses, obesity (hazard ratio [HR] 2.496; 95% confidence interval [CI] 1.094-5.695), receipt of preoperative radiation (HR 10.026; 95% CI 1.225-82.027), open surgical approach (HR 2.779; 95% CI 1.202-6.425), and number of harvested nodes (HR 1.105; 95% CI 1.026-1.190) were significantly associated with lymphocele-development.

Pelvic lymphoceles and its attendant complications represent the most commonly encountered morbidity following LPLND for rectal cancer, with obesity, neoadjuvant radiotherapy, open surgery, and higher nodal-yield predisposing to their development.

Consensus is lacking regarding the management of extramesorectal lymph nodes (EMLN) in rectal cancer. Using simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT), we targeted involved EMLN and reserved lateral pelvic lymph nodal dissection (LPLND) for nonresponders. The primary aim of this work was to determine the proportion of patients who avoided LPLND and to establish the pathological EMLN positivity rate.

Consecutive patients with rectal cancer with suspicious EMLN [short axis dimension (SAD) ≥ 7 mm], receiving SIB-IMRT as part of neoadjuvant chemoradiotherapy and subsequently undergoing total mesorectal excision (TME) or watch-and-wait, were included. Our primary objective was to determine the proportion of patients with a good nodal response (EMLN SAD < 5 mm) who were spared LPLND. The 3-year locoregional relapse rate, distant metastasis-free survival (DMFS) and overall survival (OS) were also assessed.

Of the 61 patients studied, 38 (62.3%) responded well to SIB-IMRT. In this group, 32 patients underwent TME alone and six were observed as per watch-and-wait. The remaining 23 (37.7%) patients with persistent EMLN received TME with LPLND. On pathological evaluation, 7 (30.4%) patients had positive nodes while 16 (69.6%) were negative. At a median follow-up of 32 months (95% CI 23.3-40.7 months), 10 (16.4%) patients developed distant metastases while none had local or pelvic relapse. The resultant 3-year DMFS and OS for the whole cohort were 84.4% and 95.1%, respectively. Overall, 5/61 (8.2%) patients encountered radiation-induced toxicity of grade 3 or above and 8/55 (14.5%) patients had severe postoperative complications.

SIB-IMRT targeting EMLN followed by selective LPLND exhibits excellent oncological outcomes. While patients responding to SIB-IMRT safely avoid LPLND, the potential for increased morbidity in nonresponders must be considered.

This study aimed to identify cases in which lateral lymph node (LLN) dissection (LLND) can be excluded by clarifying preoperative factors, including an evaluation of the middle rectal artery (MRA), associated with LLN metastasis.

Fifty-five consecutive patients who underwent preoperative positron emission tomography-computed tomography (PET/CT) and total mesorectal excision with LLND for rectal cancer were included. We retrospectively investigated the preoperative clinical factors associated with pathological LLN (pLLN) metastasis. We analyzed the regions of pLLN metastasis using MRA.

pLLN metastasis occurred in 13 (23.6%) patients. According to a multivariate analysis, clinical LLN (cLLN) metastasis based on short-axis size and LLN status based on PET/CT were independent preoperative factors of pLLN metastasis. The negative predictive value (NPV) was high (97.1%) in patients evaluated as negative based on PET/CT and cLLN short-axis size. MRA was detected in 24 patients (43.6%) using contrast-enhanced CT, and there was a significant relationship between pLLN metastasis and the presence of MRA. pLLN metastasis in the internal iliac region but not in the obturator region was significantly correlated with the presence of MRA.

Combined cLLN metastasis based on short-axis size and PET/CT showed a higher NPV, suggesting this to be a useful method for identifying cases in which LLND can be excluded.

Lateral lymph node dissection (LLND) can decrease local recurrence to lateral compartments in middle-low rectal cancer, but pathological evidence for optimal surgical indications, especially after neoadjuvant (chemo)radiotherapy (nCRT), is lacking. This study aimed to identify the predictive factors and oncological outcomes for different LLN locations associated with pathological metastasis.

In this multicenter study, patients from 19 centers who underwent total mesorectal excision (TME) with LLND for locally advanced mid-/low rectal cancer from January 2012 to December 2021 were included.

All 566 included patients underwent TME with LLND surgery; 241 (37.4%) of the largest LLNs were located in the obturator area, and 403 (62.6%) of the largest LLNs were located in the internal iliac area. Multivariate analysis revealed that a short-axis size of 9 mm for the obturator area and 6 mm for internal iliac nodes constituted a reliable indicator of pathological LLN metastasis in non-CRT patients. In nCRT patients, a short-axis node size of 7 mm for obturator nodes and 4 mm for internal iliac nodes could be used to accurately predict pathological LLN metastasis. In contrast to pathological internal iliac node metastasis, pathological obturator node metastasis was associated with lower distant metastasis-free survival (DMFS) (P = 0.001), cancer-specific survival (CSS) (P = 0.043), and overall survival (OS) (P = 0.009), but lower lateral local recurrence-free survival (LRFS) (P > 0.05) was not statistically significant.

The obturator and internal iliac nodes may be two completely different types of LLNs, and the optimal cutoff value for predicting pathological LLN metastasis is inconsistent regardless of nCRT. Clinical trial registration The protocol of the current study was registered on ClinicalTrials.gov (NCT04850027), and the protocols were in accordance with the standards set by the World Medical Association Declaration of Helsinki.

This study aims to analyze the safety, feasibility, and short-term oncology outcomes of selective laparoscope lateral lymph node dissection (LLND) with total mesorectal excision surgery. Between December 2019 and May 2023, LLND with total mesorectal excision surgery was performed in 47 selected patients with advanced rectal cancer. Surgical complications and 2-year oncology survival outcomes were analyzed in the study. All 47 procedures were technically successful without converting conversion to open surgery. The mean operation time was 200.6 minutes (135-321 minutes), and the mean estimated blood loss was 92.9 mL (range 10-2000 mL). The most common postoperative complications were anastomotic (8.5%, n = 4), ileus (6.4%, n = 3), and chyle leakage (4.3%, n = 2). Lateral pelvic lymph node metastases were found in 19 (40.4%) patients. When divided into lateral pelvic lymph node positive and negative groups, there was no significant impact on overall survival (94.4% vs 100%, Log-rank P = .596) and local recurrence-free survival (LFRS) (76.7% vs 89.6%, Log-rank P = .210), except disease-free survival (DFS) (58.3% vs 90.2%, Log-rank P = .005). Subgroup analysis showed similar short-term survival outcomes between the pN+ group and the internal iliac metastasis group (Log-rank P of overall survival, LFRS, and DFS were all ˃.05). LRFS and DFS in the obturator or external iliac metastasis group were worse than those in the internal iliac metastasis group when the follow-up time was extended (Log-rank P of LFRS and DFS were .05 and .063). Selective laparoscopy LLND for rectal cancer is safety and feasibility, and its complications are manageable. Oncology survival outcomes for lateral pelvic lymph node metastases limited to the internal iliac are similar to the pN+ stage; therefore, it should be treated positively.

A meta-analysis was conducted on the perioperative and oncological outcomes of robot-assisted and laparoscopic lateral lymph node dissection in rectal cancer. There are few articles and reports on this topic, and a lack of high-quality research results in unreliable research conclusions. This study includes prospective and retrospective studies to obtain more reliable findings.

Databases were searched, including PubMed, EMBASE, Cochrane, and Web of Science. The search was conducted from the time of database construction to March 2024. The quality of the literature was evaluated using the NOS scoring system. Meta-analysis was performed using R language software. Statistical heterogeneity was assessed using the I2 statistic, and sensitivity analysis was performed.

Six relevant literatures that met the criteria were finally included, and 652 patients were included, including 316 (48.5%) in the robot-assisted lateral lymph node dissection for rectal cancer group (RLLND) and 336 (51.5%) in the laparoscopic lateral lymph node dissection for rectal cancer group (LLLND). Analysis of the results showed that compared with the laparoscopic group, the robotic group had less mean intraoperative blood loss (MD = - 22, 95% CI - 40.03 to - 3.97, P < 0.05), longer operative time (MD = 51.57, 95%CI 7.69 to 95.45, P < 0.05), and a shorter mean hospital stay (MD = - 1.25, 95%CI - 2.46 to - 0.05, P < 0.05), a low rate of urinary complications (OR 0.39, 95%CI 0.23 to 0.64, P < 0.01), a low overall rate of postoperative complications (OR 0.6, 95%CI 0.42 to 0.87, P < 0.01), and a high number of lateral lymph node dissection (MD = 1.18, 95% CI 0.14 to 2.23, P < 0.05), and there was no statistically significant difference between the two groups in terms of postoperative anastomotic leakage, postoperative intestinal obstruction, and total number of lymph nodes obtained (P > 0.05).

Compared with laparoscopy, robotic lateral lymph node dissection for rectal cancer reduces intraoperative blood loss, shortens the average length of hospital stay, reduces urologic complications, decreases overall postoperative complications, and collects more lateral lymph nodes. However, the surgical time is prolonged.

To systematically review and meta-analyze the prognostic significance of lateral lymph node metastasis (LLNM) on pretreatment MRI in patients with rectal cancer who undergo neoadjuvant chemoradiation followed by curative surgical resection without lateral lymph node dissection (LLND).

We searched the MEDLINE and EMBASE databases until September 27, 2023, utilizing the following search terms: (rectal OR rectum OR colorectal) AND (lateral OR sidewall) AND (lymph OR node). The QUIPS tool was employed to evaluate methodological quality. We pooled the association between LLNM on pretreatment MRI and outcomes such as local recurrence, distant metastasis, disease-free survival, and overall survival using hazard ratio (HR) and odds ratio (OR) based on random effects model.

We included 9 studies, encompassing 3180 patients. LLNM on pretreatment MRI revealed a significant association with increased local recurrence rates (HR: 4.11; 95 % CI: [1.87, 9.02]) and elevated risks for both disease-free (HR: 1.70; 95 % CI: [1.42, 2.03]) and overall survival (HR: 1.76; 95 % CI: [1.44, 2.15]). As for distant metastasis, our analysis indicated a potential trend towards increased rates, though this did not reach statistical significance (HR: 1.67; 95 % CI: [0.85, 3.27]).

Our findings underscore the relationship between LLNM and increased local recurrence and compromised disease-free and overall survival. This emphasizes the potential limitations of relying solely on neoadjuvant chemoradiation and highlights the potential need to intensify treatment in select patients.

Information about the distribution characteristics and prognostic significance of lateral lymph nodes (LLNs) on primary computed tomography (CT) scan in rectal cancer patients is lacking.

Between January 2013 and December 2016, patients with pathologically proved rectal cancer and pretreatment abdominal enhanced CT in our department were screened. We firstly redivided LLNs into seven categories based on their locations. Then, the number and distribution of all measurable LLNs and the characteristics of the largest LLN in each lateral compartment were recorded. Furthermore, we investigated the long-term outcomes in patients with different LLN characteristics and LLN risk scoring.

A total of 572 patients were enrolled in this study. About 80% of patients had measurable LLNs, and most patients developed measurable LLNs in the obturator cranial compartment. Lateral local recurrence (LLR) was observed in 20 patients, which accounted for 83.3% of the local recurrence (LR). Patients with the largest LLN short-axis diameter >10 mm had a poor prognosis, which was similar to that in patients with simultaneous distant metastasis (SDM). Patients with LLN risk scoring ≥2 had a worse prognosis than those with LLN risk scoring <2, while better than those with SDM.

This study suggests that LLR is the main locoregional recurrence pattern. Most rectal cancer patients have measurable LLNs on primary CT scan. However, patients with enlarged LLNs <10 mm or LLN risk scoring <2 still have a significantly better prognosis than patients with SDM, which indicated the potential value of locoregional treatment for these LLNs.

Metastatic lateral pelvic lymph nodes (LPNs) in rectal cancer significantly impact the prognosis and treatment strategies. Western practices emphasize neoadjuvant chemoradiotherapy (CRT), whereas Eastern approaches often rely on LPN dissection (LPND). This review examines the evolving role of LPND in the context of modern treatments, including total neoadjuvant therapy (TNT), and the impact of CRT on the management of clinically suspicious LPNs. We comprehensively reviewed the key literature comparing the outcomes of LPND versus preoperative CRT for rectal cancer, focusing on recent advancements and ongoing debates. Key studies, including the JCOG0212 trial and recent multicenter trials, were analyzed to assess the efficacy of LPND, particularly in conjunction with preoperative CRT or TNT. Current evidence indicates that LPND can reduce local recurrence rates compared to total mesorectal excision alone in patients not receiving radiation therapy. However, the benefit of LPND in the context of neoadjuvant CRT is influenced by the size and pretreatment characteristics of LPNs. While CRT can effectively control smaller metastatic LPNs, larger or clinically suspicious LPNs may require LPND for optimal outcomes. Advances in surgical techniques, such as robotic-assisted LPND, offer potential benefits but also present challenges and complications. The role of TNT in controlling metastatic LPNs and improving patient outcomes is emerging but remains underexplored. The decision to perform LPND should be individualized based on patient-specific factors, including LPN size, response to neoadjuvant treatment, and surgeon expertise. Future research should focus on optimizing treatment protocols and further evaluating the role of TNT in managing metastatic LPNs.

This study aimed to evaluate the efficacy of lateral lymph node dissection (LLND) for rectal cancer by comparing the local control in patients with and without pathological lateral lymph node metastasis (LLNM).

We included 189 patients with rectal cancer who underwent total mesorectal excision and LLND at 13 institutions between 2017 and 2019. Patients with and without pathological LLNM were defined as the pLLNM (+) and (-) groups, respectively. Propensity score-matching helped to balance the basic characteristics of both groups. The incidences of local recurrence (LR) and lateral lymph node recurrence (LLNR) were compared between the groups.

In the entire cohort, 39 of the 189 patients had pathological LLNM. The 3-year LR and LLNR rates were 18.3% and 4.0% (p = 0.01) and 7.7% and 3.3% (p = 0.22) in the pLLNM (+) and (-) groups, respectively. After propensity score matching, the data from 62 patients were analyzed. No significant differences in LR or LLNR were observed between both groups. The 3-year LR and LLNR rates were 16.4% and 9.8% (p = 0.46) and 9.7% and 9.8% (p = 0.99) in the pLLNM (+) and (-) groups, respectively.

LLND would lead to comparable local control in the pLLNM (+) and (-) groups if the clinicopathological characteristics except for LLNM are similar.

The role of lateral pelvic lymph node dissection in the treatment of patients with locally advanced rectal cancer is a matter of controversy. Surgical practices in Korea and Japan have accepted this approach and are widely utilized; however, it is not routinely incorporated in the practice of countries in the Western hemisphere. This review will examine the role of lateral pelvic lymph node dissection.

The value of neoadjuvant chemoradiotherapy (CRT) is not absolutely clear for upper-half (> 7-15 cm) rectal cancer. This study aimed to compare the efficacy and safety of radical surgery with preoperative CRT vs. upfront surgery (US) in Chinese patients with stage II and III upper-half rectal cancer. A total of 809 patients with locally advanced upper-half rectal cancer between 2017 and 2021 were enrolled retrospectively (280 treated with CRT and 529 treated with US). Through 1:1 propensity score matching, the CRT (172 patients) and US (172 patients) groups were compared for short-term postoperative results and long-term oncological and functional outcomes. In the entire cohort, patients in the CRT group had a younger age, lower distance from the anal verge (DAV), and higher rates of cT4 stage, cN2 stage, mrCRM positivity, EMVI positivity, CEA elevation, and CA-199 elevation than those in the US group. The 5-year disease-free survival (DFS) was lower in the CRT group than in the US group (76% vs. 84%, p = 0.022), while the 5-year overall survival (OS) was comparable between the two groups (85% and 88%, p = 0.084). The distant metastasis rate was higher in the CRT group than in the US group (12.5% vs. 7.8%, p = 0.028), though the local recurrence rate was similar between the two groups (1.1% and 1.3%, p = 1.000). After performing PSM, the 5-year OS (86% vs. 88% p = 0.312), the 5-year DFS (79% vs. 80%, p = 0.435), the local recurrence rate (1.2% vs. 1.7%, p = 1.000), and the distant metastasis rate (11.0% vs. 9.3%, p = 0.593) were comparable between the two groups. Notable pathological downstaging was observed in the CRT group, with a pathological complete response (PCR) rate of 14.5%. In addition, patients in the CRT group had a lower proportion of pT3 (61.6% vs. 77.9%, p < 0.001), pN + (pN1, 15.1% vs. 30.2%, pN2, 9.3% vs. 20.3%, p < 0.001), stage III (24.4% vs. 50.6%, p < 0.001), perineural invasion (19.8% vs. 32.0%, p = 0.014), and lymphovascular invasion (9.3% vs. 25.6%, p < 0.001) than those in the US group. Postoperative complications and long-term functional results were similar, yet there was a trend toward a higher conversion to laparotomy rate (5 (2.9%) vs. 0 (0.0%), p = 0.061) and higher rates of robotic surgery (11.6% vs. 4.7%, p < 0.001), open surgery (7.0% vs. 0.6%, p < 0.001), diverting stoma (47.1% vs. 25.6%, p < 0.001), and surgery costs (1473.6 ± 106.5 vs. 1140.3 ± 54.3$, p = 0.006) in the CRT group. In addition, EMVI (OR = 2.516, p = 0.001) was the only independent risk factor associated with poor response to CRT, and in subgroup analysis of EMVI + , CRT group patients presented a lower 5-year DFS (72.9% vs. 80.5%, p = 0.025) compared to US group patients. CRT prior to surgery has no additional oncological benefits over US in the treatment of upper-half rectal cancer. In contrast, CRT is associated with increased rates of conversion to laparotomy, stoma creation and higher surgery costs. Surgeons tend to favor robotic surgery in the treatment of complex cases such as radiated upper-half rectal cancers. Notably, EMVI + patients with upper-half rectal cancer should be encouraged to undergo upfront surgery, as preoperative CRT may not provide benefits and may lead to delayed treatment effects.

Multidisciplinary management of rectal cancer has rapidly evolved over the last several years. This review describes recent data surrounding total neoadjuvant therapy, organ preservation, and management of lateral pelvic lymph nodes. It then presents our treatment algorithm for management of rectal cancer at The University of Texas MD Anderson Cancer Center in the context of this and other existing literature. As part of this discussion, the review describes how we tailor management based upon both patient and tumor-related factors in an effort to optimize patient outcomes.

A total mesenteric excision (TME) with lateral pelvic lymph node dissection (LLND) is the standard treatment for advanced low rectal cancer in Japan. Recently, neoadjuvant (chemo)radiotherapy (n(C)RT) has been used with LLND to improve outcomes at multiple Japanese institutes. This study evaluates the benefits of adding nCRT to TME with LLND.

Seventy-two consecutive patients who underwent TME and LLND with or without nCRT between 2006-2019 to treat advanced low rectal cancer were retrospectively reviewed. The clinicopathological data were compared and the risk factors for local recurrence were evaluated.

Fifty-seven patients (79.1%) underwent TME and LLND with nCRT, and 15 patients (20.9%) without nCRT. There was no significant difference in the clinicopathological characteristics except the clinical T stage. The occurrence of postoperative complications was statistically insignificant. The 5-year local recurrence rate of patients with nCRT was significantly lower than those without (4.0% versus 26.6%, in all patients, p=0.002). Multivariate analysis revealed that the absence of nCRT was an independent risk factor for local recurrences in patients who underwent TME with LLND (hazard ratio: 6.04, p=0.04).

The administration of nCRT prevented local recurrences more effectively in patients with advanced low rectal cancer who underwent TME with LLND.

Whether lateral pelvic node metastasis should be considered as a regional or systemic disease is a long-standing debate. Although previous Japanese studies have considered it to be locoregional disease, Western countries consider it a systemic disease and do not perform lateral pelvic node dissection after preoperative chemoradiotherapy.

To evaluate whether lateral pelvic node metastasis is a systemic or regional disease that is amenable to curative resection.

Retrospective analysis of a prospectively collected database.

This study was conducted at a tertiary cancer center.

There were 616 consecutive patients who underwent curative total mesorectal excision alone or with lateral pelvic node dissection after preoperative chemoradiotherapy for locally advanced rectal cancer between 2011 and 2019.

Three-year disease-free and overall survival.

A total of 360 patients underwent total mesorectal excision, and 160 patients underwent total mesorectal excision with lateral pelvic node dissection. There was no difference in the 3-year disease-free survival (DFS; p = 0.844) or overall survival rates ( p = 0.921) between the groups. Patients with lateral pelvic node metastasis showed DFS similar to those with perirectal lymph node metastasis in the total mesorectal excision group. In a subgroup analysis, patients with internal iliac pelvic node metastasis showed a disease-free survival comparable to those with perirectal node involvement, and patients with other lateral pelvic node metastasis showed a DFS similar to those with intermediate node involvement. In the lateral pelvic node dissection group, the lateral pelvic node metastatic rate was 32.5%. On multivariate analysis, fewer than 8 of the unilateral harvested lateral pelvic nodes and advanced ypT stage were significantly associated with poor disease-free survival.

The retrospective design.

Lateral lymphatic metastasis showed oncologic outcomes similar to those of upward spread, especially perirectal lymph nodes metastasis. Large cohort studies with long-term follow-up are required to confirm these results. See Video Abstract .

ANTECEDENTES:Es un debate muy antiguo si las metástasis en los ganglios pélvicos laterales deben considerarse una enfermedad regional o sistémica. Si bien estudios japoneses anteriores las consideran como una enfermedad locorregional, en los países de occidente se las considera como una enfermedad sistémica por la cual no se realiza disección de ganglios pélvicos laterales después de una radioquimioterapia preoperatoria.OBJETIVOS:Evaluar si la metástasis en los ganglios pélvicos laterales se consideran como enfermedad sistémica o enfermedad regional susceptible de resección curativa.DISEÑO:Análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:616 pacientes consecutivos se sometieron a excisión total del mesorrecto curativa sola o con disección de los ganglios pélvicos laterales después de radioquimioterapia preoperatoria en casos de cáncer de recto localmente avanzado entre 2011 y 2019.PRINCIPALES MEDIDAS DE RESULTADO:Sobrevida global y libre de enfermedad a 3 años.RESULTADOS:Un total de 360 pacientes se sometieron a excisión total del mesorrecto y 160 pacientes se sometieron a excisión total del mesorrecto con disección de ganglios pélvicos laterales.No hubo diferencias en la sobrevida libre de enfermedad a 3 años (p = 0,844) ni en las tasas de sobrevida general (p = 0,921) entre los grupos. Los pacientes con metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con metástasis en los ganglios linfáticos perirrectales que se encontraban en el grupo de excisión total del mesorrecto.En el análisis de subgrupos, los pacientes con metástasis en los ganglios pélvicos ilíacos internos mostraron una sobrevida libre de enfermedad comparable a aquellos con afección de los ganglios perirrectales y los pacientes con otras metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con afección de los ganglios intermedios.En el grupo de disección de los ganglios pélvicos laterales, la tasa de metástasis en dichos ganglios fué del 32,5%. En el análisis multivariado, < de 8 ganglios pélvicos laterales resecados unilateralmente y el estadio ypT avanzado se asociaron significativamente con una menor sobrevida libre de enfermedad.LIMITACIÓN:El diseño retrospectivo del estudio.CONCLUSIONES:Las metástasis linfáticas laterales mostraron resultados oncológicos similares a la diseminación ascendente, especialmente las metástasis en los ganglios linfáticos perirrectales. Se requieren grandes estudios de cohortes con seguimiento a largo plazo para confirmar estos resultados. (Traducción-Dr. Xavier Delgadillo ).

Total mesorectal excision (TME) is accepted as gold standard method in rectal cancer globally. But there is no standard for lateral lymph nodes. Combination of neoadjuvant treatment plus lateral lymph node dissection (LLND) in select patients might be a promising method. Our purpose is to describe the anatomic landmarks of LLND on cadavers and minimally invasive surgery.

Local advanced rectal cancer and lateral lymph node (LLN) metastasis are accepted as an indication of neoadjuvant treatment. LLND was performed according to preoperative imaging after radiochemotherapy.

Twenty-eight (10.5%) of 267 patients with rectal cancer who had suspected lateral lymph node metastasis (LLNM) with magnetic resonance imaging (MRI) underwent LLND in addition to TME after neoadjuvant chemoradiotherapy. Eight of them had LLNM. Three patients had bilateral LLND and only 1 had LLNM. The median number of harvested lymph nodes was 6. The rates of LLNM increased with the presence of poor prognosis markers. One regional and 1 distant recurrence were detected in patients who had no LLN metastasis compared with2 regional and 4 distant recurrences in the LLN-positive group.

Local advanced rectal cancer cases may benefit from LLND, but it does not appear to have an effect on overall survival. There is no consensus whether size and/or morphologic criteria in MRI are the ideal guide for LLND.

Management of lateral pelvic lymph nodes in locally advanced rectal cancer is controversial, with limited data indicating the optimal approach. In addition, no data exist regarding the treatment of lateral nodes in the setting of short-course radiation and nonoperative intent.

To evaluate a novel approach incorporating simultaneous integrated boost to suspicious lateral nodes.

A retrospective study.

This study was conducted at a large tertiary referral center.

Patients treated with radiation therapy and consolidation chemotherapy were included. All primary tumors underwent biopsy confirmation and disease staging with pelvic MRI.

Primary tumors were biopsy proven and staged with pelvic MRI. A subset of lateral pelvic lymph node patients received a simultaneous integrated boost of 35 Gy in 5 fractions. Then, chemotherapy was administered, with the majority receiving modified folinic acid, fluorouracil, and oxaliplatin. Clinical partial response required total mesorectal excision.

Patterns of failure and survival analyses by subgroup were assessed. Outcomes based on receipt of radiation were compared across node status.

Between January 2017 and January 2022, 155 patients were treated with short-course chemotherapy, with 121 included in the final analysis. Forty-nine percent of patients underwent nonoperative management. The median follow-up was 36 months and the median age was 58 years. Thirty-eight patients (26%) had positive lateral pelvic lymph nodes. Comparing lateral node status, progression-free survival was significantly worse for patients with positive disease ( p < 0.001), with a trend for worse overall survival. Receipt of nodal boost in patients with lateral nodes resulted in meaningful locoregional control. Nodal boost did not contribute to additional acute or late GI toxicity.

Limitations include retrospective nature and lack of lateral node pathology; however, a thorough radiographic review was performed.

Lateral node-positive rectal cancer is correlated with worse oncologic outcomes and higher locoregional failure. Boost to clinically positive lateral nodes is a safe approach in the setting of short course radiation and in those receiving nonoperative intent. See Video Abstract.

ANTECEDENTES:El manejo de los ganglios linfáticos pélvicos laterales en el cáncer de recto localmente avanzado es controvertido, con datos limitados que indiquen el abordaje óptimo. Además, no existen datos sobre el tratamiento de los ganglios linfáticos laterales en el contexto de la radiación de curso corto y la intención no operatoria.OBJETIVO:Evaluamos un enfoque novedoso que incorpora sobreimpresión integrada simultánea (SIB) a los linfonodos laterales sospechosos.DISEÑO:Este fue un estudio retrospectivo.ESCENARIO:Este estudio se realizó en un gran centro de referencia terciario.PACIENTES:Se incluyeron pacientes tratados con radiación y quimioterapia de consolidación. Todos los tumores primarios se confirmaron mediante biopsia y la enfermedad se estadificó con resonancia magnética pélvica.INTERVENCIONES:Los tumores primarios se confirmaron mediante biopsia y se estadificaron con RM pélvica. Un subconjunto de pacientes con linfonodos pélvicos laterales (LPLN) recibió SIB a 35 Gy en 5 fracciones. Luego, se administró quimioterapia y la mayoría recibió mFOLFOX. La respuesta clínica parcial requirió la escisión total del mesorrecto.PRINCIPALES MEDIDAS DE RESULTADO:Se evaluaron los patrones de fracaso y los análisis de supervivencia por subgrupo. Los resultados basados en el esquema de radiación se compararon según el estado de los ganglios.RESULTADOS:Entre enero de 2017 y enero de 2022, 155 pacientes fueron tratados con ciclo corto y quimioterapia con 121 incluidos en el análisis final. El 49% se sometió a manejo no operatorio. La mediana de seguimiento fue de 36 meses y la mediana de edad fue de 58 años. 38 pacientes (26%) tuvieron LPLN positivos. Comparando el estado de los ganglios laterales, la supervivencia libre de progresión fue significativamente peor para los pacientes con LPLN positiva ( p < 0,001) con una tendencia a una peor supervivencia global. La recepción de refuerzo nodal en pacientes con nodos laterales dio como resultado un control locorregional significativo. La sobreimpresión ganglionar no contribuyó a la toxicidad GI aguda o tardía adicional.LIMITACIONES:Las limitaciones incluyeron la naturaleza retrospectiva y la falta de patología de los ganglios linfáticos laterales; sin embargo, se realizó una revisión radiográfica exhaustiva.CONCLUSIONES:El cáncer de recto con ganglio lateral positivo se correlaciona con peores resultados oncológicos y mayor fracaso locorregional. La sobreimpresión a los ganglios laterales clínicamente positivos es un enfoque seguro en el contexto de un curso corto y en aquellos que siguen un manejo no operatorio. (Traducción-Dr. Felipe Bellolio ).

The aim of this study was to explore the clinical value of a radiomics prediction model based on T2-weighted imaging (T2WI) and clinical indexes in predicting lateral lymph node (LLN) metastasis in rectal cancer patients.

This was a retrospective analysis of 106 rectal cancer patients who had undergone LLN dissection. The clinical risk factors for LLN metastasis were selected by multivariable logistic regression analysis of the clinical indicators of the patients. The LLN radiomics features were extracted from the pelvic T2WI of the patients. The least absolute shrinkage and selection operator algorithm and backward stepwise regression method were adopted for feature selection. Three LLN metastasis prediction models were established through logistic regression analysis based on the clinical risk factors and radiomics features. Model performance was assessed in terms of discriminability and decision curve analysis in the training, verification and test sets.

The model based on the combined T2WI radiomics features and clinical risk factors demonstrated the highest accuracy, surpassing the models based solely on either T2WI radiomics features or clinical risk factors. Specifically, the model achieved an AUC value of 0.836 in the test set. Decision curve analysis revealed that this model had the greatest clinical utility for the vast majority of the threshold probability range from 0.4 to 1.0.

Combining T2WI radiomics features with clinical risk factors holds promise for the noninvasive assessment of the biological characteristics of the LLNs in rectal cancer, potentially aiding in therapeutic decision-making and optimizing patient outcomes.

Significant controversies exist with regards to the optimal management of lateral pelvic lymph nodes metastases (mLLN) in patients with low rectal cancer. The differing views held by Japanese and Western clinicians on the management of mLLN have been well documented. However, the adequacy of pelvic lymph node dissection (PLND) or neoadjuvant chemoradiation (NACRT) alone in addition to total mesorectal excision (TME) have recently come into question, due to the relatively high incidence of lateral local recurrences following PLND and TME, or NACRT and TME alone. Recently, a more selective approach to PLND has been suggested, involving a combination of neoadjuvant therapy, followed by PLND only to patients in whom the oncological benefit is likely to outweigh the risk of potential adverse events. A number of studies have attempted to retrospectively identify certain nodal characteristics on preoperative imaging, such as nodal size, appearance, and size reduction following neoadjuvant therapy. However, no consensus has been reached regarding the optimal criteria for a selective approach to PLND, partly due to the heterogeneity and retrospective nature of most of these studies. This review aims to provide an overview of recent evidence with regards to the diagnostic challenges, considerations for, and outcomes of the current management strategies for mLLN in rectal cancer patients.

Metastatic lateral lymph node dissection can improve survival in patients with rectal adenocarcinoma, with or without chemoradiotherapy. However, the optimal imaging diagnostic criteria for lateral lymph node metastases remain undetermined.

To develop a lateral lymph node metastasis diagnostic artificial intelligence tool using deep learning, for patients with rectal adenocarcinoma who underwent radical surgery and lateral lymph node dissection.

Retrospective study.

Multicenter study.

A total of 209 patients with rectal adenocarcinoma, who underwent radical surgery and lateral lymph node dissection at 15 participating hospitals, were enrolled in the study and allocated to training (n = 139), test (n = 17), or validation (n = 53) cohorts.

In the neoadjuvant treatment group, images taken before pretreatment were classified as baseline images and those taken after pretreatment as presurgery images. In the upfront surgery group, presurgery images were classified as both baseline and presurgery images. We constructed 2 types of artificial intelligence, using baseline and presurgery images, by inputting the patches from these images into ResNet-18, and we assessed their diagnostic accuracy.

Overall, 124 patients underwent surgery alone, 52 received neoadjuvant chemotherapy, and 33 received chemoradiotherapy. The number of resected lateral lymph nodes in the training, test, and validation cohorts was 2418, 279, and 850, respectively. The metastatic rates were 2.8%, 0.7%, and 3.7%, respectively. In the validation cohort, the precision-recall area under the curve was 0.870 and 0.963 for the baseline and presurgery images, respectively. Although both baseline and presurgery images provided good accuracy for diagnosing lateral lymph node metastases, the accuracy of presurgery images was better than that of baseline images.

The number of cases is small.

An artificial intelligence tool is a promising tool for diagnosing lateral lymph node metastasis with high accuracy.

ANTECEDENTES:Disección de nódulos linfáticos laterales metastásicos puede mejorar la supervivencia en pacientes con adenocarcinoma del recto, con o sin quimiorradioterapia. Sin embargo, aún no se han determinado los criterios óptimos de diagnóstico por imágenes de los nódulos linfáticos laterales metastásicos.OBJETIVO:Nuestro objetivo fue desarrollar una herramienta de inteligencia artificial para el diagnóstico de metástasis en nódulos linfáticos laterales mediante el aprendizaje profundo, para pacientes con adenocarcinoma del recto que se sometieron a cirugía radical y disección de nódulos linfáticos laterales.DISEÑO:Estudio retrospectivo.AJUSTES:Estudio multicéntrico.PACIENTES:Un total de 209 pacientes con adenocarcinoma del recto, que se sometieron a cirugía radical y disección de nódulos linfáticos laterales en 15 hospitales participantes, se inscribieron en el estudio y se asignaron a cohortes de entrenamiento (n = 139), prueba (n = 17) o validación (n = 53).PRINCIPALES MEDIDAS DE RESULTADO:En el grupo de tratamiento neoadyuvante, las imágenes tomadas antes del tratamiento se clasificaron como imágenes de referencia y las posteriores al tratamiento, como imágenes previas a la cirugía. En el grupo de cirugía inicial, las imágenes previas a la cirugía se clasificaron como imágenes de referencia y previas a la cirugía. Construimos dos tipos de inteligencia artificial, utilizando imágenes de referencia y previas a la cirugía, ingresando los parches de estas imágenes en ResNet-18. Evaluamos la precisión diagnóstica de los dos tipos de inteligencia artificial.RESULTADOS:En general, 124 pacientes se sometieron a cirugía solamente, 52 recibieron quimioterapia neoadyuvante y 33 recibieron quimiorradioterapia. El número de nódulos linfáticos laterales removidos en los cohortes de entrenamiento, prueba y validación fue de 2,418; 279 y 850, respectivamente. Las tasas metastásicas fueron 2.8%, 0.7%, y 3.7%, respectivamente. En el cohorte de validación, el área de recuperación de precisión bajo la curva fue de 0.870 y 0.963 para las imágenes de referencia y antes de la cirugía, respectivamente. Aunque tanto las imágenes previas a la cirugía como las iniciales proporcionaron una buena precisión para diagnosticar metástasis en los nódulos linfáticos laterales, la precisión de las imágenes previas a la cirugía fue mejor que la de las imágenes iniciales.LIMITACIONES:El número de casos es pequeño.CONCLUSIÓN:La inteligencia artificial es una herramienta prometedora para diagnosticar metástasis en los nódulos linfáticos laterales con alta precisión. (Traducción-Dr. Aurian Garcia Gonzalez ).

In Western countries, the gold-standard therapeutic strategy for rectal cancer is preoperative chemoradiotherapy (CRT) following total mesorectal excision (TME), without lateral lymph node dissection (LLND). However, preoperative CRT has recently been reported to be insufficient to control lateral lymph node recurrence in cases of enlarged lateral lymph nodes before CRT, and LLND is considered necessary in such cases. We performed a literature review on aspects of pelvic anatomy associated with rectal surgery and LLND, and then combined this information with our experience and knowledge of pelvic anatomy. In this review, drawing upon research using a 3-dimensional anatomical model and actual operative views, we aimed to clarify the essential anatomy for LLND. The LLND procedure was developed in Asian countries and can now be safely performed in terms of functional preservation. Nonetheless, the longer operative time, hemorrhage, and higher complication rates with TME accompanied by LLND than with TME alone indicate that LLND is still a challenging procedure. Laparoscopic or robotic LLND has been shown to be useful and is widely performed; however, without a sufficient understanding of anatomical landmarks, misrecognition of vessels and nerves often occurs. To perform safe and accurate LLND, understanding the landmarks of LLND is essential.

To compare the diagnostic performance of rectal CT with that of high-resolution rectal MRI and histopathology in assessing rectal cancer.

Sixty-seven patients with rectal cancer who underwent rectal CT with rectal distension using sonographic gel and high-resolution MRI were enrolled in this study. The distance from the anal verge/anorectal junction, distance to the mesorectal fascia (MRF), extramural depth (EMD), extramesorectal lymph node (LN) involvement, extramural venous invasion (EMVI), and T/N stages in rectal CT/MRI were analyzed by two gastrointestinal radiologists. The CT findings of 20 patients who underwent radical surgery without concurrent chemoradiotherapy were compared using histopathology. Interclass correlations and kappa statistics were used.

The distance from the anal verge/anorectal junction showed an excellent intraclass correlation between CT and MRI for both reviewers. For EMD, the distance to the MRF, presence of LNs, extramesorectal LN metastasis, EMVI, T stage, and intermodality kappa or weighted kappa values between CT and MRI showed excellent agreement. Among the 20 patients who underwent radical surgery, T staging, circumferential resection margin involvement, EMVI, and LN metastasis on rectal CT showed acceptable concordance rates with histopathology.

Dedicated rectal CT may be on par with rectal MRI in providing critical information to patients with rectal cancer.

Involved internal iliac and obturator lateral lymph nodes (LLNs) are a known risk factor for the occurrence of ipsilateral local recurrences (LLR) in rectal cancer. This study examined coverage of LLNs with routine radiation therapy practice in the Netherlands and associated LLR rates.

Patients with a primary tumor ≤8 cm of the anorectal junction, cT3-4 stage, and at least 1 internal iliac or obturator LLN with short axis ≥5 mm who received neoadjuvant (chemo)radiation therapy, were selected from a national, cross-sectional study of patients with rectal cancer treated in the Netherlands in 2016. Magnetic resonance images and radiation therapy treatment plans were reviewed regarding segmented LLNs as gross tumor volume (GTV), location of LLNs within clinical target volume (CTV), and received proportion of the planned radiation therapy dose.

A total of 223 out of 3057 patients with at least 1 LLN ≥5 mm were selected. Of those, 180 (80.7%) LLNs were inside the CTV, of which 60 (33.3%) were segmented as GTV. Overall, 202 LLNs (90.6%) received ≥95% of the planned dose. Four-year LLR rates were not significantly higher for LLNs situated outside the CTV compared with those inside (4.0% vs 12.5%, P = .092) or when receiving <95% versus ≥95% of the planned radiation therapy dose (7.1% vs 11.3%, P = .843), respectively. Two of 7 patients who received a dose escalation of 60 Gy developed an LLR (4-year LLR rate of 28.6%).

This evaluation of routine radiation therapy practice showed that adequate coverage of LLNs was still associated with considerable 4-year LLR rates. Techniques resulting in better local control for patients with involved LLNs need to be explored further.

Lateral pelvic lymph node (LPLN) metastasis is one of the prominent reasons for local recurrence (LR) in patients with rectal cancer (RC). The evaluation criteria of lateral lymph node dissection (LLND) for patients in eastern (mainly in Japan) and western countries have been controversial. The aim of this study was to analyse the risk factors for LPLN metastasis in order to guide surgical methods.

We searched relevant databases (Embase (Ovid), Medline (Ovid), PubMed, Cochrane Library, and Web of Science) for articles published between 1 January 2000 and 05 October 2022 to evaluate the risk factors for LPLN metastasis in patients with RC in this meta-analysis.

A total of 24 articles with 5843 patients were included in this study. The overall results showed that female sex, age <60 years, pretherapeutic CEA level >5 ng/ml, clinical T4 stage (cT4), clinical M1 stage (cM1), distance of the tumour from the anal verge (AV) <50 mm, tumour centre located below the peritoneal reflection (Rb), short axis (SA) of LPLN ≥8 mm before nCRT, short axis (SA) of LPLN ≥5 mm after nCRT, border irregularity of LPLN, tumour size ≥50 mm, pathological T3-4 stage (pT3-4), pathological N2 stage (pN2), mesorectal lymph node metastasis (MLNM), lymphatic invasion (LI), venous invasion (VI), CRM (+) and poor differentiation were significant risk factors for LPLN metastasis (P <0.05).

This study summarized almost all potential risk factors of LPLN metastasis and expected to provide effective treatment strategies for patients with LRC. According to the risk factors of lateral lymph node metastasis, we can adopt different comprehensive treatment strategies. High-risk patients can perform lateral lymph node dissection to effectively reduce local recurrence; In low-risk patients, we can avoid overtreatment, reduce complications and trauma caused by lateral lymph node dissection, and maximize patient survival and quality of life.

Total neoadjuvant therapy (TNT), which includes chemotherapy and radiation prior to surgical resection, has been recently accepted as the new standard of care for patients with locally advanced low and mid rectal cancers. Multiple clinical trials have evaluated this approach in the last several decades and demonstrated improvement in, local control and reduced risk of recurrence. In addition, in the course of these investigations, it has been shown that between a third and a half of patients experience a clinical complete response (cCR) after being treated with the TNT approach, leading to the development of new organ preservation protocol, now known as watch-and-wait (W&W). On this protocol, cCR patients are not referred for surgery after total neoadjuvant treatment. Instead, they remain on close surveillance and, thus, avoid potential complications associated with surgical resection. Multiple clinical trials are ongoing, investigating the long-term outcomes of these new approaches and the development of less toxic and more effective TNT regimens for LARC. Improvements in technology and rectal MRI protocols position radiologists as vital members of multidisciplinary rectal cancer management teams. Rectal MRI has become a critical tool for rectal cancer initial staging, treatment response assessment, and surveillance on W&W protocols. In this review, we summarize the findings of the pivotal clinical trials that contributed to establishing the current treatment paradigms in locally advanced rectal cancer (LARC) management, with the intention of helping radiologists play more effective roles in their multidisciplinary teams.

Lateral pelvic lymph node dissection improves oncological outcomes in rectal cancer patients with suspected lateral pelvic lymph node metastasis. However, the indication for this procedure remains unclear.

This study aimed to identify the predictive factors for lateral lymph node metastasis and the indications for lateral pelvic lymph node dissection.

A multi-institutional retrospective study.

This study was conducted at 3 university hospitals.

This study involved 105 patients with locally advanced mid/low rectal cancer and clinically suspected lateral pelvic lymph node metastasis who underwent total mesorectal excision with lateral pelvic lymph node dissection between 2015 and 2020.

Indications were set using lateral pelvic lymph node metastasis-associated preoperative factors.

Among 105 patients, 36 (34.3%) had pathologically confirmed lateral pelvic lymph node metastasis and 77 (73.3%) underwent preoperative chemoradiation. Tumors located within 5 cm distance from the anal verge ( p = 0.02) and initial node size ≥ 6 mm ( p = 0.001) were significant predictors of lateral pelvic lymph node metastasis. The sensitivity was 100% (36/36) with a cutoff of 6 mm for the initial node size and 94.4% (34/36) with a cutoff of 8 mm for the initial node size. When using initial node size cutoffs of 8 mm for anal verge-to-tumor distance of >5 cm and 6 mm for anal verge-to-tumor distance of ≤5 cm, the sensitivity of lateral pelvic lymph node metastasis was found to be 100%.

The retrospective design and small sample size were the limitations of this study.

Initial node size and tumor height were significant predictors of lateral pelvic lymph node metastasis. This study proposed that an initial node size of ≥8 mm with an anal verge-to-tumor distance of >5 cm and ≥6 mm with an anal verge-to-tumor distance of ≤5 cm are optimal indications for lateral pelvic lymph node dissection in rectal cancer. See Video Abstract at http://links.lww.com/DCR/C101 .

ANTECEDENTES:La disección de los ganglios linfáticos pélvicos laterales mejora los resultados oncológicos en pacientes con cáncer de recto con sospecha de metástasis en los ganglios linfáticos pélvicos laterales. Sin embargo, la indicación de este procedimiento sigue sin estar clara.OBJETIVO:Nuestro objetivo fue identificar los factores predictivos de la metástasis de los ganglios linfáticos laterales y las indicaciones para la disección de los ganglios linfáticos pélvicos laterales.DISEÑO:Estudio retrospectivo multiinstitucional.AJUSTES:Este estudio se realizó en tres hospitales universitarios.PACIENTES:Este estudio involucró a 105 pacientes con cáncer de recto medio/bajo localmente avanzado y sospecha clínica de metástasis en los ganglios linfáticos pélvicos laterales que se sometieron a una escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales entre 2015 y 2020.PRINCIPALES MEDIDAS DE RESULTADO:Las indicaciones se establecieron utilizando los factores preoperatorios asociados con la metástasis de los ganglios linfáticos pélvicos laterales.RESULTADOS:Entre 105 pacientes, 36 (34,3%) tenían metástasis en los ganglios linfáticos pélvicos laterales confirmada patológicamente y 77 (73,3%) se sometieron a quimiorradiación preoperatoria. Los tumores ubicados dentro de los 5 cm desde el borde anal ( p = 0,02) y el tamaño inicial del ganglio ( p = 0,001) fueron predictores significativos de metástasis en los ganglios linfáticos pélvicos laterales. La sensibilidad fue del 100 % (36/36), con un punto de corte de 6 mm para el tamaño inicial del ganglio, seguido de 8 mm para el tamaño inicial del ganglio (94,4%, 34/36). Cuando se utilizó un tamaño de corte inicial del ganglio de 8 mm para una distancia entre el borde anal y el tumor >5 cm y 6 mm para una distancia entre el borde anal y el tumor ≤5 cm, la sensibilidad de la metástasis en los ganglios linfáticos pélvicos laterales fue del 100 %.LIMITACIONES:El diseño retrospectivo y el pequeño tamaño de la muestra.CONCLUSIONES:El tamaño inicial del ganglio y la altura del tumor fueron predictores significativos de metástasis en los ganglios linfáticos pélvicos laterales. Este estudio propuso que un tamaño de ganglio inicial de ≥8 mm con un tumor a >5 cm del margen anal y ≥6 mm con un tumor a ≤5 cm del margen anal son indicaciones óptimas para la disección de los ganglios linfáticos pélvicos laterales en el cáncer de recto. Consulte Video Resumen en http://links.lww.com/DCR/C101 . (Traducción-Dr. Yolanda Colorado ).

The lateral pelvic sidewall is a major site of local recurrence after radical resection of rectal cancer. Salvage lateral pelvic node dissection (LPND) may be the only way to eliminate recurrent lateral pelvic nodes (LPNs). This study aimed to describe the technical details of robotic and laparoscopic salvage LPND and assess the short-term clinical and oncological outcomes in patients with recurrent LPNs who underwent salvage LPND by a minimally invasive approach for curative intent.

Between September 2010 and 2019, 36 patients who underwent salvage surgery for LPN recurrence were retrospectively analyzed from a prospectively maintained database. Patients' characteristics, index operation, MRI findings, and perioperative and pathological outcomes were analyzed.

Eleven and 14 patients underwent robotic and laparoscopic salvage LPND, respectively. Eight patients (32.0%) underwent a combined salvage operation for resectable extra-pelvic sidewall metastases. There were four cases of open-conversion during the laparoscopic approach due to uncontrolled bleeding of iliac vessels. In these patients, metastatic LPNs were suspected of iliac vessel invasion and were found to be larger in size (median 15 mm; range 12-20) than that in patients who underwent successful LPND using the minimally invasive approach (median 10 mm; range 5-20). The median number of metastatic LPNs and harvested LPNs was 1 (range 0-3) and 6 (range 1-16), respectively. Six patients (24.0%) experienced postoperative complications including lymphoceles and voiding difficulties. During the follow-up (median 44.6 months; range 24.0-87.7), eight patients developed recurrences, mainly the lung and para-aortic lymph nodes, and one patient developed pelvic sidewall recurrence after laparoscopic salvage LPND. The 3-year disease-free survival and overall survival after salvage LPND were 66.4% and 79.2%, respectively.

Robotic and laparoscopic salvage LPND for recurrent LPNs are safe and feasible with favorable short-term surgical outcomes. However, the surgical approach should be carefully chosen in patients with large-sized and invasive recurrent LPNs.

Lateral pelvic lymph node (LPLN) involvement occurs in 10%-25% of rectal cancer cases. Total mesorectal excision (TME) with routine LPLN dissection (LPLND) is predominantly applied in Japan whereas TME with neoadjuvant treatment are used in the West. LPLND is a morbid procedure and minimally invasive techniques may help reduce its morbidity. Selective lateral pelvic node dissection with TME following neoadjuvant treatment achieves acceptable disease-free and overall survival.

Standard treatment of locally advanced rectal cancer (LARC) was neoadjuvant chemoradiotherapy (CRT), followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, attempts to deliver both systemic chemotherapy and neoadjuvant CRT prior to surgery. Patients treated with neoadjuvant chemotherapy were more likely to show higher tumor regression. The objective of this trial was to increase complete clinical rate (cCR) for LARC patients by optimizing tumor response, using TNT regimen as compared to conventional chemoradiotherapy. TESS, a prospective, open-label, multicenter, single-arm, phase 2 study, is underway.

Main inclusion criteria include cT3-4aNany or cT1-4aN+ rectal adenocarcinoma aged 18-70y; Eastern Cooperative Oncology Group (ECOG) performance 0-1; location ≤5 cm from anal verge. Ninety-eight patients will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplatin) before, during, and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as Watch and Wait strategy) and adjuvant chemotherapy capecitabine 2 cycles. Primary endpoint is the cCR rate. Secondary endpoints include ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; local recurrence or metastasis; disease-free survival; locoregional recurrence-free survival; acute toxicity; surgical complications; long-term anal function; late toxicity; adverse effect, ECOG standard score, and quality of life. Adverse events are graded per Common Terminology Criteria for Adverse Events V5.0. Acute toxicity will be monitored during antitumor treatment, and late toxicity will be monitored for 3 years from the end of the first course of antitumor treatment.

The TESS trial aims to explore a new TNT strategy, which is expected to increase the rate of cCR and sphincter preservation rate. This study will provide new options and evidence for a new sandwich TNT strategy in patients with distal LARC.