Planned Liver Stereotactic Body Radiotherapy for Residual Colorectal Cancer Liver Metastases After Surgery: A Single-Arm Retrospective Study.

Given the promising outcomes of stereotactic body radiation therapy (SBRT) in treating colorectal cancer liver metastases (CRLMs), we proposed an innovative strategy combining surgery with planned liver SBRT for CRLMs. This retrospective study included patients who underwent curative-intent surgery combined with planned liver SBRT from July 2019 to October 2023. Planned liver SBRT was delivered to residual unresectable and unablatable lesions with maximum diameters of ≤5 cm. Outcomes included local failure (LF), intrahepatic recurrence-free survival (IHRFS), extrahepatic recurrence-free survival (EHRFS), progression-free survival (PFS), overall survival (OS), and radiation-related adverse events. A total of 69 patients were included. The 1-, and 2-year cumulative incidence rates of LF after SBRT were 7.7%, and 9.6%, respectively. The median PFS was 6.2 months, and the median OS was 45.8 months. Multivariate analysis identified RAS/BRAF mutations, extrahepatic metastases excluding lung involvement, and higher CEA as independent predictors of poorer OS. Intrahepatic recurrence was the predominant pattern of first disease progression after combination treatment. Acute grade 1-2 radiation-related adverse events occurred in 56.5% of patients, while grade 3 toxicities were reported in 4.3%. This approach offers favorable long-term outcomes, suggesting its potential to broaden the indications for curative-intent local treatments in CRLMs.