Total Androgen Suppression Does Not Improve Overall Survival for Certain Patients With Prostate Cancer

Study does not show clinically significant improvements in overall survival but does show benefits in secondary endpoints, which included rates of distant metastases, deaths due to prostate cancer, and PSA failure.

Adding short-term androgen suppression (ADT) to dose escalated radiotherapy (RT) did not improve overall survival (OS) for patients with intermediate-risk prostate cancer, according to the results of the NRG-RTOG 0815 trial presented at the Plenary Session of the American Society for Radiation Oncology’s (ASTRO) Annual Meeting.

The phase 3 trial enrolled 1492 eligible patients randomized into 2 treatment arms. Patients were divided 1:1, with 750 assigned to treatment with dose-escalated RT alone and 742 assigned to treatment using the same radiotherapy but adding 6 months of total androgen suppression. Patients were stratified by risk factors, comorbidity status, and radiotherapy modality before the randomization.

The results of the trial did not find any associated improvement in OS rates for patients receiving ADT. However, the trial did demonstrate clinically significant improvements in secondary endpoints, which included rates of distant metastases, deaths due to prostate cancer, and PSA failure, according to the investigators.

“While we did not demonstrate an overall survival benefit for the addition of androgen suppression to dose-escalated radiotherapy, the findings that the addition of ADT did reduce rates of biochemical failure and distant metastases highlight a crucial need for future studies, especially in the areas of advanced imaging and biomarker identification, that can optimally identify subsets of intermediate risk prostate cancer patients that are most likely to benefit from this intervention,” said Daniel J. Krauss, MD, in a press release.

“The next generation of prostate cancer radiotherapy studies are, in fact, designed to incorporate molecular biomarker characterization directly into the protocol randomization structure, a critical step that will maximize the chances of accurately identifying patients who will benefit from treatment intensification.”

Death rates between the 2 trial arms were similar, with 100 deaths occurring in the cohort receiving ADT compared to 119 in the trial group receiving dose escalated RT alone, translating to 91% and 90% OS estimates for these cohorts respectively.

REFERENCE

Total androgen suppression with dose-escalated radiotherapy does not improve overall survival in men with intermediate-risk prostate cancer: Results highlight need for biomarker studies [news release]. EurekAlert; October 26, 2021. Accessed October 27, 2021. https://www.eurekalert.org/news-releases/932715