Effect of split-course radiotherapy on survival and local control in advanced localized prostatic carcinoma

Abstract

Purpose : to analyze the effect of overall treatment time of radiotherapy on survival and local control in locally advanced prostatic cancer in a split-course treatment setting. Methods and Materials : 168 patients with Stage C prostatic cancer treated during 1979–1989 by the split-course method where the overall treatment time is protracted. Treatment consisted of whole pelvis irradiation of 40 Gy in 4 weeks, followed by a planned 3-week interruption and an additional 26 Gy by the reduced field technique to a total dose of 66 Gy in 9 weeks and 30–33 fractions. The overall treatment time varied from 55 to 100 days. Thirtyeight percent (63) of the patients were treated primarily with radiotherapy, while the rest (105) had received androgen ablative therapy during 2 to 4.5 years before radiotherapy. To examine the effect of treatment time on local control, the patients were divided into three groups (⪯ 63 days, 64–70 days, and > 70 days) by treatment time. Results : the 5-year actuarial survival rates, calculated from the date of diagnosis, were 91% for the hormonally manipulated patients and 69% for the patients treated with radiotherapy alone. The 5-year actuarial local control rates, counted from the start of radiotherapy, were 84% for radiotherapy and 80% for the hormonally manipulated group. Overall, no significant effect of treatment time could be seen, either for radiotherapy alone or for the hormonally manipulated group. The results were similar when the material was further divided by T category and histologic grade. Conclusions : no significant effect of overall treatment time (55 to 100 days) on survival or local control was found in either group. The survival time from diagnosis was longer in the hormonally pretreated group. Apparently, with adequate doses (≥ 65 Gy) the overall treatment time becomes less important for local control of advanced prostatic cancer, even in a split-course treatment setting.