Background: Total mesorectal excision (TME) remains the gold standard for the resection of rectal cancer regardless of the modality: open, laparoscopic, or robotic. The transanal TME (TaTME) approach has been utilized to overcome the difficulties encountered with the dissection of tumors in the distal pelvis. Recently, a single-port robotic approach (rSPa) was introduced, where three arms and a camera emanate from a 2.5 cm diameter port. This report presents the first experience in the United States combining those two approaches (rSPa TaTME) in rectal cancer, evaluating its safety and oncologic outcomes. Methods: This is a retrospective review of our prospectively maintained rectal cancer database. Patient demographics, tumor characteristics, neoadjuvant treatment, and oncologic and surgical outcomes were recorded. Results: Between May 2022 and August 2024, ten patients (six females, four males) with a median age at surgery of 53 years (range: 38-85) and a mean BMI of 26 (±5) kg/m2 were included for analysis. The median distance of tumors from the anorectal junction was 3.2 cm (range: 2-5.3 cm). All patients had negative margins, with eight complete TME specimens, one near complete, and one incomplete. The mean number of lymph nodes harvested was 24 (±11). The average operative time was 351 (243-411) min. The average length of stay was four days. The ileostomy was reversed in nine out of ten patients. Six patients experienced complications within 30 days of surgery. There were no local or distal recurrences, with a mean follow-up of 20 months (range: 4-30). Conclusions: rSPa TaTME is a unique and innovative method of combining two minimally advanced approaches for the resection of distal rectal cancers, with acceptable surgical and oncologic outcomes.

To some extent, the robotic technique does offer certain benefits in rectal cancer surgery than laparoscopic one, while remains a topic of ongoing debate for rectal cancer patients who have undergone neoadjuvant chemoradiotherapy (NCRT).

Potential studies published until January 2024 were obtained from Web of Science, Cochrane Library, Embase, and PubMed. Dichotomous and continuous variables were expressed as odds ratios (ORs) or weighted mean differences (WMDs) with 95% CIs, respectively. A random effects model was used if the I2 statistic >50%; otherwise, a fixed effects model was used.

Eleven studies involving 1079 patients were analysed. The robotic-assisted group had an 0.4 cm shorter distance from the anal verge (95% CI: -0.680 to -0.114, P =0.006) and 1.94 times higher complete total mesorectal excision (TME) rate (OR=1.936, 95% CI: 1.061-3.532, P =0.031). However, the operation time in the robotic-assisted group was 54 min longer (95% CI: 20.489-87.037, P =0.002) than the laparoscopic group. In addition, the robotic-assisted group had a lower open conversion rate (OR=0.324, 95% CI: 0.129-0.816, P =0.017) and a shorter length of hospital stay (WMD=-1.127, 95% CI: -2.071 to -0.184, P =0.019).

Robot-assisted surgery offered several advantages over laparoscopic surgery for locally advanced mid-low rectal cancer following NCRT in terms of resection of lower tumours with improved TME completeness, lower open conversion rate, and shorter hospital stay, despite the longer operative time.

Objective: The aim of our study was to assess the learning curve of robotic assisted low anterior resection with diverting loop ileostomy (LARDLI) for low and mid rectal cancer performed by novice in robotic-assisted surgery colorectal surgeon in a public hospital with limited access to the robotic platform. Methods: A retrospective analysis of all low and mid rectal cancer robotic-assisted operations was conducted. All procedures were performed by a single surgeon with a once per week access to the Da Vinci® Si™ Surgical System, Intuitive Surgical Inc. Demographic, clinical, and pathological data were reviewed. The cumulative sum (CUSUM) analysis was utilized to analyze learning curve for operative time. Results: A total of 107 consecutive patients who underwent LARDLI for lower and mid rectal cancer between November 2011 and July 2020 were included in the analysis. The median patients' age was 65 (range, 32-85) years, 72% were males (n = 77), and 91% (n = 97) received neoadjuvant therapy. Median operative time was 295.5 (range, 180-551) minutes. The conversion rate was 3.7% (n = 4). Median length of hospital stay was 6 (range, 1-41) days. There were 35 (32.7%) postoperative complications, of these 7 (6.5%) were major complications (≥Grade 3, according to the Clavien-Dindo classification). There was only one intraoperative complication (.9%). CUSUM analysis showed that the learning curve was 49 cases to achieve a plateau. Conclusions: The learning curve of robotic assisted low anterior resection for lower and mid rectal cancer for a novice in robotic surgery colorectal surgeon with limited access to the robotic platform is 49 cases. Surgeon and operative team dedication, alongside sufficient hospital support, may lower the number of cases of the learning curve.

This study aimed to assess the learning curve of robot-assisted intersphincteric resection for low rectal cancer.

We retrospectively analyzed the clinical data of 89 patients who underwent robot-assisted intersphincteric resection. All surgeries were performed by the same group of surgeons at our institution between June 2016 and April 2021. The learning curve was evaluated using a cumulative sum analysis and the best-fit curve. The different stages of the learning curve were compared based on patient characteristics and short-term clinical outcomes to evaluate their impact on clinical efficacy.

The minimum number of cases required to overcome the learning curve was 47. The learning curve was divided into the learning improvement and proficiency stages. Significant differences were observed in the operation time and the number of lymph nodes between the two stages (P < 0.05), whereas no significant differences were found in intraoperative blood loss, first postoperative exhaust time, postoperative complications, 3-year progression-free survival, overall survival, and local recurrence-free survival (P > 0.05).

Robotic-assisted intersphincteric resection for low rectal cancer exhibits a learning curve that can be divided into two stages: namely, learning improvement and proficiency. Achieving proficiency requires a minimum of 47 surgical cases.

With the increasing adoption of robotic surgery in clinical practice, institutions intending to adopt this technology should understand the learning curve in order to develop strategies to help its surgeons and operating theater teams overcome it in a safe manner without compromising on patient care. Various statistical methods exist for the analysis of learning curves, of which a cumulative sum (CUSUM) analysis is more commonly described in the literature. Variables used for analysis can be classified into measures of the surgical process (e.g., operative time and pathological quality) and measures of patient outcome (e.g., postoperative complications). Heterogeneity exists in how performance thresholds are defined during the interpretation of learning curves. Factors that influence the learning curve include prior surgical experience in colorectal surgery, being in a mature robotic surgical unit, case mix and case complexity, robotic surgical simulation, spending time as a bedside first assistant, and being in a structured training program with proctorship.

New platforms for robotic surgery have recently become available for clinical use; however, information on the introduction of new surgical robotic platforms compared with the da Vinci™ surgical system is lacking. In this study, we retrospectively determined the safe introduction of the new "hinotori™" surgical robot in an institution with established da Vinci surgery using four representative digestive organ operations.

Sixty-one patients underwent robotic esophageal, gastric, rectal, and pancreatic operations using the hinotori system in our department in 2023. Among these, 22 patients with McKeown esophagectomy, 12 with distal gastrectomy, 11 with high- and low-anterior resection of the rectum, and eight with distal pancreatectomy procedures performed by hinotori were compared with historical controls treated using da Vinci surgery.

The console (cockpit) operation time for distal gastrectomy and rectal surgery was shorter in the hinotori group compared with the da Vinci procedure, and there were no significant differences in the console times for the other two operations. Other surgical results were almost similar between the two robot surgical groups. Notably, the console times for hinotori surgeries showed no significant learning curves, determined by the cumulative sum method, for any of the operations, with similar values to the late phase of da Vinci surgery.

This study suggests that no additional learning curve might be required to achieve proficient surgical outcomes using the new hinotori surgical robotic platform, compared with the established da Vinci surgery.

The routine use of MRI in rectal cancer treatment allows the use of a strict definition for low rectal cancer. This study aimed to compare minimally invasive total mesorectal excision in MRI-defined low rectal cancer in expert laparoscopic, transanal and robotic high-volume centres.

All MRI-defined low rectal cancer operated on between 2015 and 2017 in 11 Dutch centres were included. Primary outcomes were: R1 rate, total mesorectal excision quality and 3-year local recurrence and survivals (overall and disease free). Secondary outcomes included conversion rate, complications and whether there was a perioperative change in the preoperative treatment plan.

Of 1071 eligible rectal cancers, 633 patients with low rectal cancer were identified. Quality of the total mesorectal excision specimen (P = 0.337), R1 rate (P = 0.107), conversion (P = 0.344), anastomotic leakage rate (P = 0.942), local recurrence (P = 0.809), overall survival (P = 0.436) and disease-free survival (P = 0.347) were comparable among the centres. The laparoscopic centre group had the highest rate of perioperative change in the preoperative treatment plan (10.4%), compared with robotic expert centres (5.2%) and transanal centres (2.1%), P = 0.004. The main reason for this change was stapling difficulty (43%), followed by low tumour location (29%). Multivariable analysis showed that laparoscopic surgery was the only independent risk factor for a change in the preoperative planned procedure, P = 0.024.

Centres with expertise in all three minimally invasive total mesorectal excision techniques can achieve good oncological resection in the treatment of MRI-defined low rectal cancer. However, compared with robotic expert centres and transanal centres, patients treated in laparoscopic centres have an increased risk of a change in the preoperative intended procedure due to technical limitations.

Colorectal cancer is the third most common cancer and the second highest cause of cancer-related mortality worldwide. About 5%-10% of patients are diagnosed with locally advanced rectal cancer (LARC) on presentation. For LARC invading into other structures (i.e. T4b), multivisceral resection (MVR) and/or pelvic exenteration (PE) remains the only potential curative surgical treatment. MVR and/or PE is a major and complex surgery with high post-operative morbidity. Minimally invasive surgery (MIS) has been shown to improve short-term post-operative outcomes in other gastrointestinal malignancies, but there is little evidence on its use in MVR, especially so for robotic MVR.

To assess the feasibility and safety of minimally invasive MVR (miMVR), and compare post-operative outcomes between robotic and laparoscopic MVR.

This is a single-center retrospective cohort study from 1st January 2015 to 31st March 2023. Inclusion criteria were patients diagnosed with cT4b rectal cancer and underwent MVR, or stage 4 disease with resectable systemic metastases. Patients who underwent curative MVR for locally recurrent rectal cancer, or metachronous rectal cancer were also included. Exclusion criteria were patients with systemic metastases with non-resectable disease. All patients planned for elective surgery were enrolled into the standard enhanced recovery after surgery pathway with standard peri-operative management for colorectal surgery. Complex surgery was defined based on technical difficulty of surgery (i.e. total PE, bladder-sparing prostatectomy, pelvic lymph node dissection or need for flap creation). Our primary outcomes were the margin status, and complication rates. Categorical values were described as percentages and analysed by the chi-square test. Continuous variables were expressed as median (range) and analysed by Mann-Whitney U test. Cumulative overall survival (OS) and recurrence-free survival (RFS) were analysed using Kaplan-Meier estimates with life table analysis. Log-rank test was performed to determine statistical significance between cumulative estimates. Statistical significance was defined as P < 0.05.

A total of 46 patients were included in this study [open MVR (oMVR): 12 (26.1%), miMVR: 36 (73.9%)]. Patients' American Society of Anesthesiologists score, body mass index and co-morbidities were comparable between oMVR and miMVR. There is an increasing trend towards robotic MVR from 2015 to 2023. MiMVR was associated with lower estimated blood loss (EBL) (median 450 vs 1200 mL, P = 0.008), major morbidity (14.7% vs 50.0%, P = 0.014), post-operative intra-abdominal collections (11.8% vs 50.0%, P = 0.006), post-operative ileus (32.4% vs 66.7%, P = 0.04) and surgical site infection (11.8% vs 50.0%, P = 0.006) compared with oMVR. Length of stay was also shorter for miMVR compared with oMVR (median 10 vs 30 d, P = 0.001). Oncological outcomes-R0 resection, recurrence, OS and RFS were comparable between miMVR and oMVR. There was no 30-d mortality. More patients underwent robotic compared with laparoscopic MVR for complex cases (robotic 57.1% vs laparoscopic 7.7%, P = 0.004). The operating time was longer for robotic compared with laparoscopic MVR [robotic: 602 (400-900) min, laparoscopic: Median 455 (275-675) min, P < 0.001]. Incidence of R0 resection was similar (laparoscopic: 84.6% vs robotic: 76.2%, P = 0.555). Overall complication rates, major morbidity rates and 30-d readmission rates were similar between laparoscopic and robotic MVR. Interestingly, 3-year OS (robotic 83.1% vs 58.6%, P = 0.008) and RFS (robotic 72.9% vs 34.3%, P = 0.002) was superior for robotic compared with laparoscopic MVR.

MiMVR had lower post-operative complications compared to oMVR. Robotic MVR was also safe, with acceptable post-operative complication rates. Prospective studies should be conducted to compare short-term and long-term outcomes between robotic vs laparoscopic MVR.

The hinotori™ Surgical Robot System was approved for use in colorectal cancer surgery in Japan in 2022. This robot has advantages, such as an operation arm with eight axes, an adjustable arm base, and a flexible three-dimensional viewer, and is expected to be utilized in rectal cancer surgery. Herein, we report the world's first surgery for rectal cancer using the hinotori™ Surgical Robot System.

A 71-year-old woman presented to our hospital with bloody stools. A colonoscopy revealed type 2 advanced cancer in the rectum, and a histological examination exposed a well-differentiated adenocarcinoma. Abdominal enhanced computed tomography divulged rectal wall thickening without significant swelling of the lymph nodes or distant metastasis. Pelvic magnetic resonance imaging showed tumor invasion beyond the intrinsic rectal muscle layer. The patient was diagnosed with cStage IIa (cT3N0M0) rectal cancer and underwent low anterior resection using the hinotori™ Surgical Robot System. Based on an adequate simulation, surgery was safely performed with appropriate port placement and arm base-angle adjustment. The operating time was 262 min, with a cockpit time of 134 min. Subsequently, the patient was discharged 10 days postoperatively without complications. The pathological diagnosis was pStage IIA (cT3N0M0) and the circumferential resection margin was 6 mm.

We report the first case of low anterior resection for rectal cancer using the hinotori™ Surgical Robot System, in which a safe and appropriate oncological surgery was performed.