LAUSR

Key Points Question What is the optimal minimum duration of androgen deprivation therapy (ADT) when treating high-risk prostate cancer with high-dose radiotherapy? Findings This patient-level cohort study of 3 cohorts found a significant interaction between the type of high-dose radiotherapy (external beam radiotherapy with or without a brachytherapy boost) and optimal duration. Prolonging ADT for 18 to 28 months was associated with a 63% reduction in death or metastasis with external beam radiotherapy; when a brachytherapy boost was added, the nonlinear association between ADT and distant metastasis-free survival was broad and spanned 12 months. Meaning The findings of this cohort study suggest that patients receiving external beam radiotherapy alone may benefit from ADT durations of 18 months or more; if a brachytherapy boost is added, a duration of 18 months or possibly less may be optimal.