Prognostic impact of conversion hepatectomy for initially unresectable colorectal liver metastasis.

PURPOSE: This study aimed to evaluate the prognostic impact of conversion hepatectomy in patients with initially unresectable colorectal liver metastasis (CRLM) and to identify prognostic factors after conversion hepatectomy. METHODS: Correlations of conversion hepatectomy with relapse-free survival (RFS) and overall survival (OS) were retrospectively investigated in 554 consecutive patients who underwent hepatectomy for CRLM in 2000-2017. Prognostic factors after conversion hepatectomy were examined in multivariable analysis. RESULTS: Five hundred and nine patients (92%) had initially resectable CRLM at diagnosis and underwent hepatectomy (primary resection group) and 45 (8%) underwent conversion hepatectomy following chemotherapy (conversion group). The 5-year RFS was 30.0% in the primary resection group and 19.8% in the conversion group (p = 0.042); the respective 5-year OS rates were 62.0% and 52.4% (p = 0.253). Multivariable analysis did not identify conversion hepatectomy as a significant prognostic factor for RFS (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.64-1.37, p = 0.796) or OS (HR 1.12, 95% CI 0.67-1.79, p = 0.667). In the conversion group, multivariable analysis identified the following independent prognostic factors: timing of liver metastases for RFS (synchronous: HR 3.14, 95% CI 1.20-8.24, p = 0.020) and preoperative CEA level for RFS (> 5 ng/ml: HR 3.10, 95% CI 1.45-6.61, p = 0.003) and OS (> 5 ng/ml: HR 3.29, 95% CI 1.18-9.17, p = 0.023). CONCLUSIONS: RFS and OS rates after conversion hepatectomy were not inferior to those after primary resection in patients with CRLM. Patients with a normal CEA level before hepatectomy can be expected to have good long-term prognosis after conversion hepatectomy.