Zeliadt SB et al. (2006) Survival benefit associated with adjuvant androgen deprivation therapy combined with radiotherapy for high- and low-risk patients with nonmetastatic prostate cancer. Int J Radiat Oncol Biol Phys 66: 395–402

Randomized, clinical trials have demonstrated a clear survival benefit for men with high-risk (locally advanced) prostate cancer who receive advujant androgen-deprivation therapy (ADT) in addition to radiotherapy, and these findings have led to widespread use of this treatment—even for men with low-risk (organ-confined) tumors. Zeliadt and colleagues assessed prostate-cancer survival in a large, US-population-based cohort of men treated with adjuvant ADT and radiotherapy during the 1990s; they found the first population-level evidence of a survival benefit for this therapy only in men with high-risk disease.

Data for the study were obtained from the Surveillance, Epidemiology, and End Results and Medicare databases. The authors identified 31,643 men aged 65–85 years with nonmetastatic prostate cancer who had received adjuvant ADT in combination with radiotherapy. Men with T3–T4 prostate cancer experienced improved 5-year and 8-year survival, but those with stage T1–T2 prostate cancer showed no survival benefit over the 8 years following therapy, although it is possible that a benefit might be observed with extended follow-up. Instrumental variable analysis, a statistical tool that replicates randomization in observational data, was used to control for unmeasured selection bias.

ADT, especially long-term ADT, is associated with considerable side effects and morbidity, which should be weighed against its potential survival benefit. The authors advise that clinicians should follow current practice guidelines, which recommend that adjuvant ADT should be added to radiotherapy only for men with high-risk prostate cancer.