11C-Choline PET/CT and Stereotactic Ablative Radiotherapy in Prostate Cancer
Posted: Monday, December 14, 2020
Sean S. Park, MD, PhD, of the Mayo Clinic, Rochester, Minnesota, and colleagues observed an estimated 2-year overall survival of 80% in patients with heavily treated castration-resistant prostate cancer after receiving stereotactic ablative radiotherapy to oligometastases identified by 11C-choline PET/CT (Cho-PET). “These results are favorable compared to historical series and support the study of Cho-PET and [stereotactic ablative radiotherapy] in castration-resistant prostate cancer in phase III trials,” stated the study authors. The results of the phase II trial were presented during the virtual edition of the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 4006).
This single-arm study enrolled 94 patients with castration-resistant disease, up to 3 metastases identified on Cho-PET, and a life expectancy of more than 6 months. Of the 89 patients included in the study analysis, 58 patients had 1 lesion, 23 had 2 lesions, and 8 had 3 lesions. Prior to stereotactic ablative radiotherapy (n = 80), 61%, 52%, and 20% had experienced disease progression on second-line chemotherapy, abiraterone, or enzalutamide, respectively. The median prostate-specific antigen (PSA) level when stereotactic ablative radiotherapy was administered was 0.7 ng/mL, and 64% had a PSA level less than 2 ng/mL.
The 1- and 2-year rates of overall survival were 96% and 80%, and the cumulative incidence of PSA disease progression at 1 and 2 years was 58% and 76%, respectively. At a median follow-up of 23 months, the median overall survival was 29 months. As for safety, no grade 3 or higher adverse events were noted, and the rate of grade 2 adverse events was low.
Disclosure: For full disclosures of study authors, visit redjournal.org.