Akademik Veri Yönetim Sistemi
ADVANCES IN RADIATION ONCOLOGY, sa.7, 2024 (ESCI)
Purpose: Emerging data suggest that metastasis -directed therapy (MDT) improves outcomes in patients with oligometastatic castration -sensitive prostate cancer (omCSPC). Prostate -specific membrane antigen positron emission tomography (PSMA-PET) can detect occult metastatic disease, and PSMA response has been proposed as a biomarker for treatment response. Herein, we identify and validate a PSMA-PET biomarker for metastasis -free survival (MFS) following MDT in omCSPC. Methods and Materials: We performed an international multi -institutional retrospective study of patients with omCSPC, defined as <= 3 lesions, treated with metastasis -directed stereotactic ablative radiation who underwent PSMA-PET/computed tomography (CT) before and after (median, 6.2 months; range, 2.4-10.9 months) treatment. Pre- and post -MDT PSMA-PET/CT maximum standardized uptake value (SUV max ) was measured for all lesions, and PSMA response was defined as the percent change in SUV max of the least responsive lesion. PSMA response was both evaluated as a continuous variable and dichotomized into PSMA responders, with a complete/partial response (at least a 30% reduction in SUV max ), and PSMA nonresponders, with stable/progressive disease (less than a 30% reduction in SUV max ). PSMA response was correlated with conventional imaging -defined metastasis -free survival (MFS) via Kaplan -Meier and Cox regression analysis. Results: A total of 131 patients with 261 treated metastases were included in the analysis, with a median follow-up of 29 months (IQR, 18.5-41.3 months). After stereotactic ablative radiation, 70.2% of patients were classified as PSMA responders. Multivariable analysis demonstrated that PSMA response as a continuous variable was associated with a significantly worse MFS (hazard ratio = 1.003; 95% CI, 1.001-1.006; P = .016). Patients classified as PSMA responders were found to have a significantly improved median MFS of 39.9 versus 12 months ( P = .001) compared with PSMA nonresponders. Our study is limited as it is a retrospective review of a heterogenous population. Conclusions: After stereotactic ablative radiation, PSMA-PET response appears to be a radiographic biomarker that correlates with MFS in omCSPC. This approach holds promise for guiding clinical management of omCSPC and should be validated in a prospective setting. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of American Society for Radiation Oncology. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).