Pathological features of rectal cancer after preoperative radiochemotherapy.

The standard therapy for rectal carcinoma is surgical, however, preoperative radiochemotherapy will play an increasing role especially in locally advanced disease. To estimate the prognosis and the effect of radiochemotherapy the postradiochemotherapeutical pathological features are important to assess. We examined the surgical specimens of 17 patients after preoperative radiochemotherapy to estimate and grade the histological reactions. A proposal for a grading system for tumor regression (not yet available in the literature) has also been described. All but one of the carcinomas showed different degrees of tumor regression. A total regression was not observed after standardised pathological work up. In only one case a locally curative resection was not possible. We think that preoperative radiochemotherapy is able to reduce tumor mass thus achieving operability in non-curatively operable cases. We recommend standards of pathological work up and regression grading for further studies comparing surgery and radiochemotherapy of rectal carcinoma.