Risk assessment of extrahepatic recurrence after liver resection for colorectal liver metastases

Although the prognosis of colorectal liver metastasis (CRLM) has improved with advances in pharmacotherapy and surgical techniques, extrahepatic recurrence (EHR) remains a significant poor prognostic factor in patients with colorectal cancer (CRC). EHR may also be a barrier to the potential curative option of liver transplantation (LT) for CRLM. This study aimed to investigate predictive factors associated with EHR after liver resection for CRLM. We analyzed 184 patients who underwent liver resection for CRLM between May 2005 and June 2021, using Cox proportional hazards regression analysis to examine the factors associated with EHR. Among 184 patients, EHR was observed in 98 patients (53.2 %). The 5-year overall survival rate was 63.6 %, 5-year recurrence-free survival rate was 40.2 %, and 5-year EHR rate was 52.2 % in the overall cohort of patients undergoing curative resection for CRLM. Multivariate analysis identified vessel invasion of primary CRC lesion, CEA ≥7.0 before liver resection, and tumor burden score (TBS) ≥12 of CRLM lesion as independent factors associated with EHR. The additive score including these three factors allowed the stratification of the risk of EHR after liver resection. Vessel invasion of primary lesion, CEA level before liver resection, and TBS of CRLM lesion are predictors of EHR after liver resection for CRLM, providing perspective on the oncological selection criteria for curative-intent locoregional therapy for CRLM including LT as well as liver resection.