Significant effects of preoperative intraluminal brachytherapy on the survival rate after resection of rectal carcinoma.

We investigated whether or not preoperative intraluminal brachytherapy (IBT) contributes to a prolongation of the survival after resection of rectal carcinoma. Eighty-five patients with middle and lower rectal carcinoma with penetration into or through the rectal wall were treated with preoperative IBT (30 Gy) and radical resection. The patients were divided into the major effect group (n=59, proportion of remaining viable cells less than 25% of the background stroma) and the minor effect group (n=26, proportion of viable cells over 25%). The major effect group had more down-staged tumors, and a lower rate of positive nodes. Local recurrence rate, distant recurrence rate, and survival rate of the major effect group were 9% (31% in the minor effect group), 15% (55% in minor group) and 74% (36% in minor group), respectively (all parameters: p<0.05). Multivariate analysis indicated that nodal involvement, tumor depth, and proportion of viable cells were the prognostic factors. Preoperative IBT affected not only the tumor morphology but also the prognosis. Our criterion of the proportion of residual viable cells was significantly correlated to the patients' survival. The analyses revealed the positive effects of IBT on the prognosis of rectal cancer.