Survival benefit for early hormone ablation in biochemically recurrent prostate cancer

Abstract

Purpose To determine whether early initiation of androgen ablation in patients with biochemically recurrent prostate cancer, but without clinically evident metastases, is associated with improved overall or disease-specific survival. To describe subgroups, based on PSA kinetics, which are most likely to benefit from early androgen ablation. Materials and Methods A retrospective cohort of 124 patients, who were definitively treated by external beam radiotherapy between 1988 and 1999, and subsequently received androgen ablation for biochemical (92 patients) or clinically metastatic (32 patients) failure, was reviewed. Median follow-up time was 6.2 years. Overall survival, disease-specific survival, and hormonal control were examined and compared for patients whose hormone ablation was started early (prostate-specific antigen [PSA] ≤15 ng/ml or PSA doubling time >7 months) or late in the course of their biochemical failure. Results All patients had biochemical response to hormone initiation, with a median PSA nadir of 0.05 ng/ml. Early initiation of hormone ablation resulted in statistically significant improvement in all outcome measures. Multivariate analysis indicated that PSA doubling time at hormone initiation was the most consistent predictor of outcome. The 5-year overall survival was 78% for patients whose androgen ablation was initiated at doubling time ≤7 months and 93% for patients when initiated at doubling time >7 months. Mean survival improved from 84.9 ± 4.6 (doubling time ≤7) to 115.3 ± 8.4 months (doubling time >7). Survival for patients started on hormones with doubling time <5 months was similar to that of patients with clinical metastases. Conclusions This survival benefit justifies the use of androgen ablation in patients whose doubling time approaches 7 months. A randomized trial is needed to confirm these findings, investigate potential benefit for patients with longer doubling times, and gather data on the morbidity of early hormone ablation, including quality of life issues.