D'Amico AV et al. (2004) 6-month androgen suppression plus radiation therapy vs radiation therapy alone for patients with clinically localized prostate cancer. JAMA 292: 821–827

The addition of 3 years of androgen suppression therapy (AST) to 70 Gy radiation therapy has been shown to improve survival in patients with high-grade clinically localized prostate cancer. Long-term AST, however, is associated with considerable toxicity. D'Amico and colleagues performed a prospective study to determine whether the addition of 6 months of AST to 70 Gy 3D-CRT also confers a survival benefit.

Patients with clinically localized prostate cancer (n = 206) were randomized to receive 70 Gy 3D-CRT alone (n = 104) or in combination with six months of AST (n = 102). AST consisted of an LHRH agonist (leuprolide acetate or goserelin) in combination with flutamide. Salvage AST was initiated in all patients following PSA failure, once the PSA level reached 10 ng/ml. Median follow-up was 4.52 years.

Patients treated with 3D-CRT plus AST had a twofold reduction in risk of death compared with those treated with 3D-CRT alone. Overall five-year survival was estimated at 88% (95% CI 80–95%) and 78% (95% CI 68–88%) for the two groups, respectively. This survival benefit was related to a lower cumulative incidence of prostate cancer-specific mortality (PCSM) in the 3D-CRT plus AST group (P = 0.02), since there was no significant difference in non-PCSM (P = 0.31). Additionally, survival free of salvage AST was significantly higher in the 3D-CRT plus AST group than in patients treated with 3D-CRT only (P = 0.002).

In conclusion, the addition of a 6-month course of AST to 70 Gy 3D-CRT gave an overall survival benefit in this study. This approach may minimize the adverse events associated with long-term AST.