Fifteen-year survival outcomes following primary androgen-deprivation therapy for localized prostate cancer

Abstract

Importance: One in 6 American men will be diagnosed as having prostate cancer during their lifetime. Although there are no data to support the use of primary androgen-deprivation therapy (ADT) for early-stage prostate cancer, primary ADT has been widely used for localized prostate cancer, especially among older patients.

Objective: To determine the long-term survival impact of primary ADT in older men with localized (T1/T2) prostate cancer.

Design, setting, and participants: This was a population-based cohort study of 66,717 Medicare patients 66 years or older diagnosed from 1992 through 2009 who received no definitive local therapy within 180 days of prostate cancer diagnosis. The study was conducted in predefined US geographical areas covered by the Surveillance, Epidemiology, and End Results (SEER) Program. Instrumental variable analysis was used to assess the impact of primary ADT and control for potential biases associated with unmeasured confounding variables. The instrumental variable comprised combined health services areas with various usage rates of primary ADT. The analysis compared survival outcomes in the top tertile areas with those in the bottom tertile areas.

Main outcomes and measures: Prostate cancer-specific survival and overall survival.

Results: With a median follow-up of 110 months, primary ADT was not associated with improved 15-year overall or prostate cancer-specific survival following the diagnosis of localized prostate cancer. Among patients with moderately differentiated cancers, the 15-year overall survival was 20.0% in areas with high primary ADT use vs 20.8% in areas with low use (difference: 95% CI, -2.2% to 0.4%), and the 15-year prostate cancer survival was 90.6% in both high- and low-use areas (difference: 95% CI, -1.1% to 1.2%). Among patients with poorly differentiated cancers, the 15-year cancer-specific survival was 78.6% in high-use areas vs 78.5%, in low-use areas (difference: 95% CI, -1.8% to 2.4%), and the 15-year overall survival was 8.6% in high-use areas vs 9.2% in low-use areas (difference: 95% CI, -1.5% to 0.4%).

Conclusions and relevance: Primary ADT is not associated with improved long-term overall or disease-specific survival for men with localized prostate cancer. Primary ADT should be used only to palliate symptoms of disease or prevent imminent symptoms associated with disease progression.

Figure. Adjusted Prostate Cancer-Specific Survival and Overall Survival in High Use and Low Use of Health Service Areas (HSAs) by Cancer Grade

Results were adjusted for age, race, comorbidity status, cancer stage, zip code income, zip code education, urban area, marital status, year of diagnosis, state buy-in status. A, Prostate cancer-specific survival was similar in areas with high and low use of primary androgen deprivation therapy (ADT) (high use and low use, respectively) among men with moderately differentiated cancer and poorly differentiated cancer. B, Overall survival was similar in highland low-use areas among men with moderately differentiated cancer and poorly differentiated cancer.