Because the optimal timing of the institution of antiandrogen therapy for prostate cancer is controversial, we compared immediate and delayed treatment in patients who had minimal residual disease after radical prostatectomy.

Ninety-eight men who underwent radical prostatectomy and pelvic lymphadenectomy and who were found to have nodal metastases were randomly assigned to receive immediate antiandrogen therapy, with either goserelin, a synthetic agonist of gonadotropin-releasing hormone, or bilateral orchiectomy, or to be followed until disease progression. The patients were assessed quarterly during the first year and then semiannually.

After a median of 7.1 years of follow-up, 7 of 47 men who received immediate antiandrogen treatment had died, as compared with 18 of 51 men in the observation group (P=0.02). The cause of death was prostate cancer in 3 men in the immediate-treatment group and in 16 men in the observation group (P<0.01). At the time of the last follow-up, 36 men in the immediate-treatment group (77 percent) and 9 men in the observation group (18 percent) were alive and had no evidence of recurrent disease, including undetectable serum prostate-specific antigen levels (P<0.001). In the observation group, the disease recurred in 42 men; 13 of the 36 who were treated had a complete response to local treatment or hormonal therapy (or both), 16 died of prostate cancer, and 1 died of another disease. The remaining men in this group were alive with progressive disease at the time of the last follow-up or had had a recent relapse. Except for the treatment group (immediate therapy or observation), no clinical or histologic characteristic significantly influenced the outcome.

Immediate antiandrogen therapy after radical prostatectomy and pelvic lymphadenectomy improves survival and reduces the risk of recurrence in patients with node-positive prostate cancer.