Phase II Trial of Enzalutamide and Androgen Deprivation Therapy with Salvage Radiation in Men with High-Risk Prostate-specific Antigen Recurrent Prostate Cancer: The STREAM Trial - Beyond the Abstract

Men with prostate-specific antigen (PSA) recurrences after prostatectomy have a high rate of failure despite salvage radiation and androgen deprivation therapy (ADT). We hypothesized that more potent inhibition of the androgen receptor may lead to radiosensitization and improved outcomes in these men. In this three-center prospective study known as the STREAM trial, we investigated the safety and effectiveness of enzalutamide given with salvage radiation therapy and ADT in men with PSA recurrence but no radiographic evidence of disease within four years of prostatectomy.

The majority of men treated had high-risk prostate cancer. Thirty-seven men completed therapy and all had testosterone recovery at two years. Nearly two-thirds of men (65%) were in remission and off therapy at two years. Men with resected node-positive disease (n = 8) had poorer outcomes, with only 25% in remission at two years, suggesting the need for escalation of therapy in this subgroup. There were no grade 4 or 5 or unexpected toxicities. 

Patient-reported quality of life data showed worsening of bowel, bladder, and hormonal symptoms at three months but recovery by 24 months in most men. Overall, we found that adding six months of oral daily enzalutamide to standard salvage radiation and hormone therapy is safe and may improve prostate cancer remission rates at two and three years. Randomized trials of ADT with or without potent androgen receptor inhibition are needed in this curative-intent setting. 

Written by: Rhonda L. Bitting, MD, Instructor in the Department of Medicine, Duke University School of Medicine, Durham, North Carolina, and Andrew J. Armstrong, MD, Professor of Medicine, Associate Professor in Pharmacology and Cancer Biology, Professor in Surgery, Member of the Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina.

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