Posted: Friday, June 16, 2023
Adding radiotherapy to standard-of-care systemic treatment did not seem to improve overall survival in patients with low-volume de novo metastatic castration-sensitive prostate cancer, according to Alberto Bossi, MD, of the Institute Gustave Roussy, Villejuif, France, and colleagues. The results of an analysis of the multicenter phase III PEACE-1 trial, which were presented during the 2023 American Society for Clinical Oncology (ASCO) Annual Meeting (Abstract LBA5000), suggested this population experienced the best survival outcomes with the addition of both abiraterone acetate plus prednisone and radiotherapy.
A total of 1,172 patients were randomly assigned to receive standard-of-care treatment (androgen-deprivation therapy with or without docetaxel) alone or plus abiraterone acetate and prednisone, with (n = 584; low-volume: n = 252) or without (n = 588; low-volume: n = 253) the addition of radiotherapy. Radiotherapy did not prolong the median duration of radiographic progression–free survival (with: 2.6 years; without: 3.0 years; hazard ratio [HR] = 1.12). According to the investigators, the median duration of radiographic progression–free survival was improved with (HR = 0.49; P < .0001) and borderline improved without (HR = 0.74; P = .066) radiotherapy in patients who received abiraterone acetate plus prednisone versus the standard of care alone. The hazard ratio between the arms treated with abiraterone acetate plus prednisone was 0.66.
The investigators reported that, in terms of overall survival, the predefined threshold for a statistical interaction was not reached (P = .11). Radiotherapy was not found to significantly improve overall survival outcomes; the median durations were 7.5 and 6.9 years with and without radiotherapy, respectively (HR = 0.97; P = .81). The median duration of overall survival was 7.1 years with the standard of care alone and not reached with the addition of both abiraterone acetate plus prednisone and radiotherapy. Data regarding whether radiotherapy may prevent severe urinary symptoms are pending.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.