Prognostic value of pathological response to chemo radiotherapy of locally advanced low rectal cancer

Background: Preoperative chemo radiotherapy improves the prognosis of locally advanced low rectal cancer and induces a pathological response in the tumor, which may have prognostic value. Aim: To assess the results of rectal cancer treatment according to the degree of pathological response of the tumor after chemo radiotherapy. Patients and Methods: All patients with a locally advanced rectal cancer located within 11 cm of the rectal margin, subjected to preoperative chemo radiotherapy followed by surgical treatment in a period of 13 years, were included. Pathological response was classified as complete, intermediate and poor. The tumor was staged according to TNM 2002 classification. Survival was analyzed with Kaplan Meier curves and Cox regression. Results: Patients were followed for a mean of 50 months (range 18-156). Exclusive and global local relapse was observed in 3 and 9.6% of patients, respectively. Pathological response was complete in 13 patients (none died), intermediate in 23 (three died) and poor in 68 (22 died). Global five years survival was 74%. There was a concordance of 0.64 between survival and pathological response. The concordance between survival and TNM classification was 0.69. Conclusions: The pathological response of the tumor to chemo radiotherapy has a good concordance with prognosis, although it is not superior to the final pathological status