PREOPERATIVE IRRADIATION OF T3-CARCINOMA IN BILHARZIAL BLADDER - COMPARISON BETWEEN HYPERFRACTIONATION AND CONVENTIONAL FRACTIONATION

The present report deals with a prospective randomized study investigating the value of pre-operative telecobalt irradiation in the management of T3-carcinoma in Bilharzial bladder. A total pre-operative dose of 4000 rad was split into 2 equal courses with a gap of 1 week. Two dose-time regimens were compared: split-course conventional fractionation, 200 rad/day (SC) and hyperfractionation (HF). In the latter, the daily dose amounted to 1000 rad and was divided into 17 hourly acute fractions, 60 rad each. The SC and HF regimens produced equivalent local tissue reactions. Hyperfractionation, however, was associated with a somewhat higher incidence of radiation sickness. Both regimens resulted in an increase of the 2-year disease-free survival rate from 19 ± 10% ( 3 16) to 53 ± 9% ( 17 32) without added surgical hazard; both HF and SC appeared to be equally effective. An appreciable post-irradiation tumor shrinkage was noted in the majority of patients; this is consistent with a rapid tumor cell turnover rate. Moreover the likelihood of long term local tumor control seemed to be greater in the more rapidly shrinking tumors. This is proposed to be linked to a more extensive reoxygenation process. No correlation was obtained between the quantitative scoring of the cytohistological radiation effect and the outcome of treatment. © 1979.