BOSTON, MA -- NRG Oncology researchers reported that adding external radiation therapy to standard brachytherapy did not improve progression-free survival for men with intermediate-risk prostate cancer. The initial primary endpoint results of NRG-RTOG 0232: A Phase III Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy with Brachytherapy Alone for Selected Patients with Intermediate-Risk Prostatic Carcinoma were presented at today's plenary session of the American Society for Radiation Oncology (ASTRO) Annual Meeting in Boston, Massachusetts.
"NRG-RTOG 0232 was initiated to determine if external beam therapy with brachytherapy would be a potentially more effective means to treat prostate cancer and prolong progression-free survival," says Bradley R. Prestidge, MD, of the DePaul Medical Center at the Bon Secours Cancer Institute and lead author of NRG-RTOG 0232.
NRG-RTOG 0232 randomized 588 men with prostate cancer, clinical stage T1c-T2b and either a Gleason Score (GS) of 2-6/PSA 10-20 or GS 7/PSA <10, to external beam radiation therapy plus brachytherapy (n=292) vs. brachytherapy alone (n=296). The study was designed to test for a 10% increase in 5-year progression-free survival (PFS) for the external beam plus brachytherapy arm.
Results from NRG-RTOG 0232 indicated there were no significant differences in baseline characteristics between arms. At the fifth of five planned interim analyses, based on the required 443 patients for that analysis, five-year PFS was 85% for the external beam radiation therapy plus brachytherapy arm and 86% for the brachytherapy only arm. Toxicity in both groups was limited, but there were significantly fewer late effects, mostly genitourinary, noted in the brachytherapy alone arm. Based on this final interim analysis, the NRG Oncology Data Monitoring Committee recommended reporting the results early.
"The results of this study are a testament to the efforts of NRG Oncology, which continues to define and strive for a new standard of care for patients with prostate cancer," stated Walter J. Curran, Jr., MD, an NRG Oncology Group Chair and Executive Director of the Winship Cancer Institute of Emory University.
NRG-RTOG 0232 was funded by grants from the National Cancer Institute.
NRG Oncology conducts practice-changing, multi-institutional clinical and translational research to improve the lives of patients with cancer. Founded in 2012, NRG Oncology is a Pennsylvania-based nonprofit corporation that integrates the research of the National Adjuvant Breast and Bowel Project, the Radiation Therapy Oncology Group, and the Gynecologic Oncology Group. The research organization seeks to carry out clinical trials with emphases on gender-specific malignancies, including gynecologic, breast, and prostate cancers, and on localized or locally advanced cancers of all types. NRG Oncology's extensive research organization comprises multidisciplinary investigators, including medical oncologists, radiation oncologists, surgeons, physicists, pathologists, and statisticians, and encompasses more than 1300 research sites located world-wide with predominance in the United States and Canada. NRG Oncology is supported primarily through grants from the National Cancer Institute (NCI) and is one of five research groups in the NCI's National Clinical Trials Network.