Duration of Androgen Deprivation Therapy for High-Risk Prostate Cancer: Application of Randomized Trial Data in a Tertiary Referral Cancer Center

Introduction: We evaluated the incidence and predictors of the use of long-term (2-3 years) versus shorter term androgen deprivation therapy (ADT) in radiation-managed men with high-risk prostate cancer.

Patients and methods: We identified 302 patients from the Dana-Farber Cancer Institute patient registry who had been diagnosed with high-risk prostate cancer (T3a or prostate-specific antigen [PSA] > 20 ng/mL or Gleason score 8-10) from 1993 to 2015. We assessed the intended duration of ADT and used multivariable Cox regression to evaluate the predictors of receiving a shorter course of ADT than recommended by the guidelines (< 2 years).

Results: The course of ADT intended by physicians increased after the 2008/2009 publication of trials showing the superiority of long-term versus short-term ADT, with 43.5% intending ≥ 2 years before versus 61.4% after (P = .014). Starting in 2010, 49.4% of patients actually received < 2 years of ADT. The most common reasons for receipt of shorter course ADT were intolerance of ADT side effects, patient comorbidity/age, the presence of T3a on magnetic resonance imaging only as the sole high-risk feature, or participation in a clinical trial. Moderate to severe comorbidity assessed using the Adult Comorbidity Evaluation-27 (adjusted hazard ratio [AHR] = 2.94), Gleason score < 8 (AHR = 5.66), and PSA < 20 ng/mL (AHR = 4.19) all predicted for receipt of shorter course ADT (P < .05 for all).

Conclusion: In a tertiary-care setting, the rates of long-course ADT for high-risk disease have increased since the 2008/2009 trials supporting its use. However, approximately one half of patients continued to receive shorter course ADT, often because of intolerance of side effects, underlying comorbidity, or physician judgment about the aggressiveness of the disease.