2186 - Precision Radiotherapy and Survival Benefit in Colorectal Liver Metastases: A Dual-Cohort Real-World Study
Presenter(s)
G. Ren1, Z. Song1, and Y. Wang2; 1Department of Radiotherapy, Peking University Shougang Hospital, Beijing, China, 2Department of Radiotherapy, Air Force Medical Center, Beijing, China
Purpose/Objective(s): The optimal local therapy for colorectal liver metastases (CRLM) is debated. While external beam radiotherapy (EBRT) is a promising modality, its patient selection criteria remain undefined. This study evaluates the survival benefit of EBRT and identifies potential responsive subpopulations.
Materials/Methods: Using retrospective data from the SEER database and an in-house cohort, we compared survival outcomes among CRLM patients receiving different local therapies. Propensity score matching (PSM) was employed to balance cohorts, and Cox regression analysis assessed the impact of EBRT and identified effect modifiers.
Results:
EBRT was associated with a significant reduction in cancer-specific mortality, without increasing non-cancer deaths, both in non-surgical (HR=0.879, 95% CI: 0.802-0.962, P=0.005) and surgical patients (HR=0.851, 95% CI: 0.758-0.956, P=0.007). After PSM with SEER patients, our 29 EBRT-treated patients showed a strong trend towards improved median overall survival (23 vs. 18 months) and reduced mortality risk (HR=0.654, 95% CI: 0.411-1.039, P=0.076). Subgroup analyses identified patients with rectal primary tumors, localized disease, and those pursuing combination therapy for non-localized disease as potential optimal candidates for EBRT.Conclusion: EBRT confers a significant survival benefit in CRLM patients, including those undergoing surgery. The therapy's efficacy appears particularly pronounced in specific subpopulations, providing crucial evidence for refining patient selection and advancing the integration of EBRT into CRLM treatment paradigms.