OBJECTIVETo evaluate the short-term outcomes and perioperative safety of proximally extended resection for locally advanced rectal cancer after neoadjuvant chemoradiotherapy.

METHODSFrom colorectal cancer database in The Sixth Affiliated Hospital of Sun Yat-sen University, a cohort of patients who underwent neoadjuvant chemoradiotherapy(1.8-2.0 Gy per day, 25-28 fractions, concurrent fluorouracil-based chemotherapy) followed by curative sphincter-preserving surgery for locally advanced rectal cancer between May 2016 and June 2017 were retrospectively identified. Exclusion criteria were synchronous colon cancer, intraoperatively confirmed distal metastasis, multiple visceral resection, and emergency operation. Thirty-one patients underwent proximal extended resection and two were excluded for incomplete extended resection, then 29 patients were enrolled as the extended group. Using propensity scores matching with 1/1 ration, 29 locally advanced rectal cancer patients who underwent conventional resection after neoadjuvant chemoradiotherapy at the same time were matched as the conventional group. Clinical data of two groups were analyzed, and the baseline characteristics and short-term outcomes were compared using the t test, χtest, or Mann-Whitney U test.

RESULTSTwo groups were well balanced with respect to the baseline characteristics after propensity score matching. As compared with conventional group, patients in extended group had longer surgical specimen [(18.8±5.1) cm vs.(11.6±3.4) cm, t=6.314, P=0.000] and longer proximal resection margin [(14.8±5.5) cm vs.(8.2±3.0) cm, t=5.725, P=0.000], but also had longer total operating time [(322.4±100.7) min vs.(254.6±70.3) min, t=2.975, P=0.004] and more intraoperative blood loss [100(225) ml vs. 100(50) ml, Z=-2.403, P=0.016]. No significant differences were observed in the length of distal resection margin, ratio of positive resection margin, number of retrieved lymph node, time of analgesic use, time of draining tube use, time to first flatus, time to first oral diet, and postoperative hospital stay. During the perioperative period of 30 days, the morbidity of complication in extended group and conventional group was 17.2%(5/29) and 34.5% (10/29), respectively (P=0.134).

CONCLUSIONProximally extended resection is a radical and safe surgical alternative for locally advanced rectal cancer after neoadjuvant chemoradiotherapy, which can potentially reduce the risk of anastomosis complication.