Preoperative radio-chemotherapy response as prognostic factor in colorectal cancer

In order to demonstrate if radiotherapy (RT) is able to reduce the number of local recurrences and to increase the survival rate of patients (pts) with colorectal cancer, the authors are participating in a large randomized international trial with the goal of comparing patients treated with preoperative radiotherapy plus surgery and patients treated only by surgery. The authors noticed that some patients treated with preoperative radiotherapy showed a reduction in tumor size at the time of endorectal ultrasonography. The authors considered the incidence of recurrences in patients responsive to radiotherapy (RT responsive group), in patients non responsive to radiotherapy (RT non responsive group) and in patients not treated with radiotherapy (no RT group) with the aim of establishing if the responsiveness to preoperative radiotherapy could be considered a prognostic factor in colorectal cancer. After a three year follow-up RT responsive group (41 pts) showed no recurrences (0%); RT non responsive group (27 pts) showed 7 (25%) recurrences; no RT group (66 pts) showed 27 (41%) recurrences. Our data indicates that responsiveness to preoperative RT can be considered a prognostic factor. A large number of patients is required to confirm this observation.