Multinational phase 3 study of prostate radiotherapy in de novo metastatic castration-sensitive prostate cancer

The phase 3 PEACE-1 study, at 77 centers in European countries, evaluated prostate radiotherapy for patients with de novo metastatic castration-sensitive prostate cancer (mCSPC). In a 1:1:1:1 factorial design, patients were randomized to standard of care (n=296), standard of care plus abiraterone (n=292), standard of care plus radiotherapy (n=293), or standard of care plus abiraterone plus radiotherapy. The median radiographic progression-free survival in these four groups was 3.0 years, 4.4 years, 2.6 years, and 7.5 years, respectively. Overall survival was not significantly influenced by radiotherapy. In the safety analysis, at least one grade 3 or worse adverse event was reported for 58.8% of patients who received radiotherapy and 56.1% of patients who did not receive radiotherapy. The authors conclude that combining radiotherapy plus standard of care plus abiraterone improves radiographic progression-free survival but not overall survival in patients with low-volume de novo mCSPC.