Proposal of "borderline resectable" colorectal liver metastases based on analysis of risk factors for early surgical failure.

Purpose: We aimed to define borderline resectable colorectal liver metastases (CRLM) based on the analysis of risk factors for early surgical failure and investigate the efficacy of neoadjuvant chemotherapy in these patients.

Methods: This was a retrospective analysis of a multi-institutional cohort of patients diagnosed with technically resectable CRLM. Early surgical failure within 6 months of liver surgery was defined as ESF6. We classified CRLM into three grades (A, B, and C) according to the definition of the Japanese Society for Cancer of the Colon and Rectum.

Results: Among the 249 patients with technically resectable CRLM, 46 (18.5%) developed ESF6. The survival rate of these patients was significantly lower than that of the patients without ESF6. In the multivariate analysis of synchronous CRLM patients, no neoadjuvant chemotherapy, Grade B/C, and Charlson comorbidity index ≥ 3 were independent predictors of ESF6. Among patients with synchronous and Grade B/C CRLM, ESF6 rates, surgical failure-free survival, and overall survival in the neoadjuvant chemotherapy group were significantly better relative to the upfront surgery group.

Conclusions: Patients with synchronous and Grade B/C CRLM are at a high risk of early surgical failure, have a poor long-term prognosis, and can be defined as borderline resectable and good candidates for neoadjuvant chemotherapy.