Oncological outcomes in extended intervals time betweeen preoperative chemoradiation with capecitabine and surgery in operable rectal adenocarcinoma: Experience at the National Cancer Institute of Peru.

Abstract

e15158 Background: The literature reports that longer interval between the end of neoadjuvantchemoradiotherapy (CRT) and surgery is associated with a better rate of pathologic complete response (pCR) in rectal cáncer. Optimal interval remains to be defined. The effects of the extended time intervals on the prognosis are not clear. The objective was to assess whether extended time intervals ( < 8, 8-12, > 12-20 and > 20 weeks) between the end of neoadjuvant CRT and surgery improve overall survival (OS), disease-free survival (DFS) and pathological outcomes Methods: Aretrospective study was conducted for 124 patients with rectal adenocarcinoma without evidence of metástasis (T1-4/N0-2/M0) at the time of diagnosis that underwent surgery with curative intent after neoadjuvant CRT with capecitabine and obtained R0 or R1 resection between January 2010 to December 2014 at National Cancer Institute of Peru. Patients undergoing emergency surgery and R2 resection have been excluded. Survival curves were calculated according to Kaplan-Meier method and compared with log-rank test Results: Of the 124 patients, 72 were women (58.1%). The average age was 59.5 years. All received neoadjuvant CRT. Rates of pCR in the four groups were 25.0%, 10.3%, 7.7% and 17.2%, respectively. No significant difference was found between the association of the radial (P = 0.418) and distal edge (P = 0.487), with time interval groups and similarly with resected (P = 0.308) and compromised nodules (p = 0.783). The median OS follow-up time was 39.5 months and for DFS was 34 months. No significant differences were observed in OS (p = 0.739) and DFS (p = 0.902) according to the four groups studied. Conclusions: We found that amplifying the time interval at 31.9 weeks did not change the mean radial and distal edge. It does not affect the mean of resected and compromised nodules and does not improve overall survival and disease-free survival. The present study is the only one that reports these results at these time intervals. It allows to extend the intervals of time for future studies that finally will define the best time interval for the surgery.