Impact of Time Interval Between Chemoradiation and Surgery on Pathological Complete Response and Survival in Rectal Cancer

Background: Limited data are available regarding the impact of time duration between chemoradiation (CRT) and surgery on pathological complete response (PCR). A PCR translates into better overall and disease free survival. The objective of this study was to determine effect of time duration on outcome after preoperative CRT in rectal cancer. Materials and
Methods: A retrospective review of patients undergoing operations for rectal adenocarcinoma between January 2005 and December 2010 was performed. Patients were divided in two groups: Group 1 underwent surgery in ≤ 8weeks post neoadjuvant CRT and Group 2 after 8 weeks. Patient characteristics, surgical procedure, histopathological details and number of loco regional and distant failures were compared. Expected 5 year overall survival and disease free survival was calculated using Kaplan Meier curves and significance was determined using the log rank test.
Results: There were 66 patients in group 1 and 93 in group 2. No significant difference in PCR was observed between the two. However, estimated 5 year DFS was significantly higher in Group 1 (66.7%) as compared to Group 2 (53.8%) (P=0.04). Estimated overall 5 year overall survival was not significantly different at 68.2% versus 54.3% (P= 0.09).
Conclusions: Delaying surgery more than 8 weeks after preoperative CRT does not impact for PCR in rectal cancer.