Published online Jun 7, 2020. doi: 10.3748/wjg.v26.i21.2877
Peer-review started: January 7, 2020
First decision: February 19, 2020
Revised: April 17, 2020
Accepted: April 28, 2020
Article in press: April 28, 2020
Published online: June 7, 2020
Lateral lymph node metastasis is one of the leading causes of local recurrence in patients with advanced mid or low rectal cancer. Neoadjuvant chemoradiotherapy (NCRT) can effectively reduce the postoperative recurrence rate; thus, NCRT with total mesorectal excision (TME) is the most widely accepted standard of care for rectal cancer. The addition of lateral lymph node dissection (LLND) after NCRT remains a controversial topic.
To investigate the surgical outcomes of TME plus LLND, and the possible risk factors for lateral lymph node metastasis after NCRT.
This retrospective study reviewed 89 consecutive patients with clinical stage II-III mid or low rectal cancer who underwent TME and LLND from June 2016 to October 2018. In the NCRT group, TME plus LLND was performed in patients with short axis (SA) of the lateral lymph node greater than 5 mm. In the non-NCRT group, TME plus LLND was performed in patients with SA of the lateral lymph node greater than 10 mm. Data regarding patient demographics, clinical workup, surgical procedure, complications, and outcomes were collected. Multivariate logistic regression analysis was performed to evaluate the possible risk factors for lateral lymph node metastasis in NCRT patients.
LLN metastasis was pathologically confirmed in 35 patients (39.3%): 26 (41.3%) in the NCRT group and 9 (34.6%) in the non-NCRT group. The most common site of metastasis was around the obturator nerve (21/35) followed by the internal iliac artery region (12/35). In the NCRT patients, 46% of patients with SA of LLN greater than 7 mm were positive. The postoperative 30-d mortality rate was 0%. Two (2.2%) patients suffered from lateral local recurrence in the 2-year follow up. Multivariate analysis showed that cT4 stage (odds ratio [OR] = 5.124, 95% confidence interval [CI]: 1.419-18.508; P = 0.013), poor differentiation type (OR = 4.014, 95%CI: 1.038-15.520; P = 0.044), and SA ≥ 7 mm (OR = 7.539, 95%CI: 1.487-38.214; P = 0.015) were statistically significant risk factors associated with LLN metastasis.
NCRT is not sufficient as a stand-alone therapy to eradicate LLN metastasis in lower rectal cancer patients and surgeons should consider performing selective LLND in patients with greater LLN SA diameter, poorer histological differentiation, or advanced T stage. Selective LLND for NCRT patients can have a favorable oncological outcome.
Core tip: Lateral lymph node metastasis is one of the leading causes of local recurrence in patients with advanced mid or low rectal cancer. Lateral local recurrence remains a significant clinical problem associated with severe morbidity and low salvage likelihood. There is an East (mainly Japan)-West divide regarding the management of lateral lymph nodes associated with lower rectal cancer. Preoperative chemoradiotherapy followed by total mesorectal excision is a standard procedure in the west. Our study shows that lateral lymph node metastasis cannot be eradicated by neoadjuvant chemoradiotherapy. Selective total mesorectal excision plus lateral lymph node dissection should be performed in advanced mid or low rectal cancer patients.