LAUSR

BACKGROUND Identifying preoperative risk factors of local recurrence and patterns of treatment failure resulting after rectal cancer management is important for planning treatment strategies and improving the results of multidisciplinary care. OBJECTIVE To analyze the associations between the preoperative factors and local recurrence, and investigate the local recurrence areas in patients with locally advanced lower rectal cancer who underwent lateral pelvic lymph node dissection. DESIGN A retrospective cohort design. SETTINGS A single institution. PATIENTS Overall 469 patients with locally advanced lower rectal adenocarcinoma located below the peritoneal reflex who received curative resection with lateral pelvic lymph node dissection during 2010-2018. MAIN OUTCOME MEASURES Independent risk factors for local recurrence were assessed using multivariate Cox regression. Local recurrence was classified into four areas using follow-up images. RESULTS Two hundred eighty-six patients underwent upfront surgery, 132 patients received neoadjuvant chemotherapy followed by surgery, and 51 patients received preoperative chemoradiotherapy followed by surgery. Eighty-six patients (18.3%) were extramural venous invasion positive and 113 patients (24.1%) were circumferential resection margin positive. The median follow-up period was 46 months. Local recurrence showed significant association with extramural venous invasion positive (hazard ratio: 2.596; 95% confidence interval: 1.321-5.102; p=0.006) or circumferential resection margin positive (hazard ratio: 2.298; 95% confidence interval: 1.158-4.560; p=0.017). The incidence of local recurrence was observed in 51 patients (10.8%), with the pelvic plexus and internal iliac area being the most frequent (6.6%), followed by the central pelvis area (3.8%), and was markedly low in the obturator area (0.4%). LIMITATIONS A retrospective, single-institution design. CONCLUSIONS Extramural venous invasion status or circumferential resection margin status were associated with a high local recurrence rate in patients who underwent lateral pelvic lymph node dissection. Further, local recurrence in the obturator area was low compared with that in other areas. http://links.lww.com/DCR/B683.