Study Finds Optimal Duration of Androgen Deprivation Therapy for Prostate Cancer

A study identified the optimal androgen deprivation therapy (ADT) duration to enhance overall survival (OS) in men with intermediate- and high-risk prostate cancer receiving radiotherapy. The results were presented at the 2022 American Society for Radiation Oncology Annual Meeting.

This meta-analysis, conducted by presenting author Nicholas G. Zaorsky, MD, MS, and colleagues, comprised 10,266 patients with a median follow-up of 11.3 years. Intention-to-treat (ITT) and ADT durations were both assessed, and the impact of ADT duration was adjusted for age, prostate-specific antigen, Gleason score, CT stage, radiotherapy dose, pelvic nodal radiotherapy use, and mid-trial enrollment year using inverse probability of treatment weighting. Multivariable additive Cox modeling was used to discern the correlation between the primary end point, which was OS, and ADT duration.

 The results of the ITT meta-analysis demonstrated marked improvements in OS as the result of extending ADT from 9 to 18 months (hazard ratio [HR]=0.77; 95% CI, 0.68-0.86; P<.0001) and from 18 to 28-36 months (HR=0.78; 95% CI, 0.68-0.89; P=0.0002). The investigators noted that the optimal duration of ADT for OS was 28 months. Adjusted based on compliance data, they showed that the optimal ADT duration was actually 21 months.

“For men enrolled in the context of randomized trials, after accounting for much of the noncompliance with durations of ADT beyond 18 months, we demonstrate that 21 months is optimal for OS in men with intermediate- and high-risk prostate cancer. While longer durations of ADT provide incremental benefit on [prostate cancer-specific mortality], this must be balanced against potential worsening of [other-cause mortality], cost, and quality of life.”

Source: Zaorsky NG, Sun Y, Nabid A, et al. Optimal duration of androgen deprivation therapy (ADT) with definitive radiotherapy for prostate cancer: an individual patient data (IPD) meta-analysis from the International MARCAP Consortium. Abstract 222. Presented at the 2022 ASTRO Annual Meeting; October 23-26, 2022; San Antonio, TX.