Effect Of Interval Time Between Neoadjuvant Chemoradiotherapy And Operation For Rectal Cancer On Clinical And Oncological Outcome

Objective: To evaluate the effect of prolonging operation interval time to 70 days after chemoradiotherapy on the short-term clinical and oncological outcome.Methods: Neoadjuvant chemoradiotherapy patients with locally advanced rectal cancer are divided into short interval group(<70 days)and long interval group(≥70 days)according to the interval time between chemoradiotherapy and surgery.The surgical difficulty,postoperative complications,pathological complete response,disease-free survival and overall survival were analyzed in both groups.Results: There were no significant differences between the two groups in basic information and clinical features of tumors before neoadjuvant chemoradiotherapy.The operation time of long interval group was significantly longer than short interval group.The sphincter-preserving rate of middle and low rectal cancer in short interval group(62.07%)was higher than that in long interval group(55.38%),and the incidence ofanastomotic leakage in short interval group(2.78%)was lower than that in long interval group(13.89%),but none were Statistical differences.The number of tumors downstaging in short interval group was significantly higher than long interval group(68.97% vs 50.77%),but the pathological complete remission rate was higher in long interval group(16.92%)than that in short interval group(15.52%).Multivariate analysis showed that pathological complete response was not associated with interval time.The median follow-up time was 39(6-84)months.The 3-year disease-free survival was 75.9% in short interval group and 66.3% in long interval group and the 3-year overall survival was 86.2% in short interval group and83.1% in long interval group,but none were Statistical differences.Conclusions: After neoadjuvant chemoradiotherapy for locally advanced rectal cancer,prolonging interval time to 70 days will significantly increase operation time 、 decrease tumor downstaging rate.Nevertheless,it has no effect on the sphincter-preserving rate,pathological complete response rate,short-term clinical and oncological outcome.