Possibilities for and limits of upfront surgical strategy with lateral pelvic node dissection for low rectal cancer.

BACKGROUND: Metastatic lateral pelvic nodes represent an important cause of pelvic recurrence in low rectal cancer patients even after preoperative chemoradiotherapy. This study aimed to evaluate the prognostic benefit of an upfront lateral pelvic nodes dissection strategy. METHODS: A total of 175 consecutive patients with stage II/III low rectal adenocarcinoma who underwent mesorectal excision with lateral pelvic nodes dissection between 1998 and 2013 were identified. Regional lateral pelvic nodes were categorized as LD2 nodes (internal iliac, hypogastric and obturator) and LD3 nodes (external iliac, common iliac, lateral sacral, presacral and sacral promontory) according to the current Japanese Society for Cancer of the Colon and Rectum classification. RESULTS: Five-year cumulative risks of local recurrence and recurrence-free survival were 4.8% and 78.1% for stage II patients, and 11.8% and 61.7% for stage III patients, respectively. Among stage III patients, no differences were observed in cumulative risks of local recurrence (5 years: 9.3% vs 14.7%, P= 0.463) and recurrence-free survival (5 years: 65.1 vs 61.2%, P = 0.890) between lateral pelvic nodes (-) and LD2 (+) patients. In multivariate analyses, metastatic lateral pelvic nodes had no impact on cumulative risks of local recurrence (hazard ratioadj: 1.389; 95% confidence interval: 0.409-4.716) and recurrence-free survival (hazard ratioadj: 0.884; 95% confidence interval: 0.425-1.837). CONCLUSIONS: Metastatic lateral pelvic nodes had no impact on cumulative risks of local recurrence and recurrence-free survival based on an upfront lateral pelvic nodes strategy. Lateral pelvic nodes can improve recurrence and survival outcomes in locally advanced low rectal cancer patients with metastatic lateral pelvic nodes.