Feasibility of Selective Lateral Node Dissection Based on Magnetic Resonance Imaging in Rectal Cancer After Preoperative Chemoradiotherapy.

Background: Lateral pelvic node metastasis is one of the major causes of local recurrence in advanced rectal cancer after preoperative chemoradiotherapy (CRT). However, lateral pelvic node dissection (LPND) is still a challenging surgical procedure in terms of surgical morbidity. This study aimed to investigate the feasibility and safety of LPND in patients with advanced rectal cancer after preoperative CRT.

Materials And Methods: Records of 80 consecutive patients who underwent total mesorectal excision (TME) with LPND for initially enlarged lateral pelvic nodes (LPNs) (short-axis diameter ≥5 mm on magnetic resonance imaging before preoperative CRT) between 2011 and 2016 were retrospectively reviewed. Surgical outcomes of these patients were compared with those of 281 patients who underwent TME alone.

Results: Ninety-nine LPND procedures were performed, including 19 bilateral LPNDs. Pathologically proven LPN metastasis was identified in 32 (32.3%) LPND cases after preoperative CRT. Multiple (odds ratio = 12.908, 95% confidence interval: 3.355-49.660, P < 0.001) and persistently enlarged LPNs (odds ratio = 27.093, 95% confidence interval: 6.072-120.896, P < 0.001) were independently associated with LPN metastasis. The rates of overall postoperative 30-d morbidity (42.5% versus 32.4%, P = 0.093) and urinary retention (11.3% versus 7.1%, P = 0.230) were similar between the TME with LPND and TME-only groups.

Conclusions: The postoperative morbidity of TME with LPND was comparable with TME-only group. The rate of LPN metastasis remained high after preoperative CRT, especially in patients with multiple or persistently enlarged LPNs.