Evaluating predictive factors for determining the presence of lateral pelvic node metastasis in rectal cancer patients following neoadjuvant chemoradiotherapy.

Objective: The need or otherwise for lateral pelvic node dissection (LPND) in rectal cancer patients with clinical lateral pelvic node metastasis (LPNM) after neoadjuvant chemoradiotherapy (nCRT) is controversial. This study was designed to explore the predictive factors for pathological LPNM in rectal cancer patients with clinical LPNM after nCRT.

Methods: From January 2010 to February 2018, a consecutive series of patients with rectal cancer and clinical LPNM after nCRT who underwent total mesorectal excision and LPND were reviewed. Patient demographics, operative and pathological outcomes were collected and analysed.

Results: A total of 76 consecutive cases were included in this study: 53 (69.7%) patients underwent unilateral LPND and 23 (30.3%) bilateral LPND. The pathological results showed that LPNM was found in 13 (17.1%) patients. Multivariate logistic regression analysis showed that the post-nCRT lateral pelvic node size ≥ 5 mm (OR = 7.67, 95% CI = 1.45-40.63, P = 0.017) and mucinous/signet-ring adenocarcinoma (OR = 4.60, 95% CI = 1.11-19.08, P = 0.035) were independent risk factors for pathological LPNM.

Conclusions: Post-nCRT lateral pelvic node size ≥ 5 mm and mucinous/signet-ring adenocarcinoma were independent predictive factors of pathological LPNM for rectal cancer patients with clinical LPNM after nCRT, and patients with these characteristics may benefit from LPND.