Impact of tumor response on survival after radiochemotherapy in locally advanced rectal carcinoma.

In locally advanced rectal adenocarcinoma, preoperative radiochemotherapy induces tumor response. The impact of pathologic tumor response on survival is still debated because of the numerous distinct tumor-response gradings available in the literature and the lack of standardized pathologic approach. The objective of this work was to study the impact of tumor response on survival, according to the 4 main tumor-response gradings available in the literature in locally advanced rectal adenocarcinoma after preoperative radiochemotherapy. From 1995 to 2004, 292 consecutive patients with cT3-T4 and/or N+ rectal adenocarcinoma were enrolled. Tumor response was evaluated according to ypTN-response gradings (downstaging: ypT0-2 N0 and complete pathologic response: ypT0 N0) and cellular-response gradings (ie, Mandard et al's and Rodel et al's gradings). The impact of tumor-response gradings and of different clinicopathologic variables on 5-year disease-free and overall survival were studied by univariate and multivariate analyses. We found that all tumor-response gradings were associated with survival. However, multivariate analysis showed that downstaging was the only tumor-response grading that influenced survival independently. In the subgroup of stage II patients (n=99), we also observed no difference on both 5-year disease-free and overall survival between low and high responders according to cellular response. In conclusion, in our experience, downstaging is the only tumor-response grading that influenced survival independently in locally advanced rectal adenocarcinomas. Cellular-response gradings had no impact on survival even in stage II patients.