Adjuvant estrogen following radiation therapy for stage C adenocarcinoma of the prostate: long-term results of a prospective randomized study.

Seventy-eight patients with clinical Stage C adenocarcinoma of the prostate were prospectively randomized to receive either radiation alone or radiation and adjuvant estrogen (diethylstilbestrol). No patient had received any prior definitive treatment for cancer. Forty patients were randomized to receive radiotherapy only and 38 patients to receive radiotherapy and estrogen. The median follow-up for all surviving patients was 14.5 years. Whether analyzed according to the original randomization or according to the treatment actually received, disease-free survival in the adjuvant estrogen group was strikingly and significantly higher than in the radiation-only group. At 5, 10, and 15 years patients receiving adjuvant estrogen had respective disease-free survival rates of 71%, 63%, and 63% compared with 49%, 43%, and 35% in patients having radiation only (p = 0.008). However, because of greater intercurrent disease-related mortality in patients receiving estrogen, there was no improvement in survival. This study suggests that a prospective randomized evaluation of early androgen deprivation with orchiectomy or with one of the nonestrogenic agents should be undertaken and that patients receiving early androgen deprivation should not be included in series reporting on the curative potential of radiation as a single modality.