Comprehensive data of 5085 patients newly diagnosed with colorectal liver metastasis between 2013 and 2017: Fourth report of a nationwide survey in Japan.

The Joint Committee for Nationwide Survey on colorectal liver metastasis (CRLM) was established to improve treatment outcomes in patients with CRLM. The aim of this study was to evaluate the transition in the characteristics and treatment strategies of patients with CRLM and to analyze the prognostic factors. The data of 5085 patients newly diagnosed between 2013 and 2017 were compared with those of 3820 patients from 2005 and 2007. In patients who underwent hepatectomy (n = 2759 and 2163), the number of CRLMs was significantly higher and in the 2013-2017 data than in the 2005-2007 data (median 2 vs. 1; p = .005). Overall survival (OS) rates after diagnosis of CRLM after hepatectomy were better in the 2013-2017 data than that in the 2005-2007 data (5-year OS, 62.4% vs. 56.7%, p < .001). Recurrence-free survival (RFS) after hepatectomy was comparable between the groups (5-year RFS, 30.5% vs. 30.7%; p = .068). Multivariate analyses identified age at diagnosis of CRLM ≥70 years, lymph node metastasis of primary lesion, preoperative carbohydrate antigen (CA) 19-9 value >100 U/mL, number of CRLM 2-4, and R2 resection as independent predictors of OS. Synchronous CRLM, concomitant extrahepatic metastasis, lymphatic invasion, lymph node metastasis of primary lesion, preoperative CA19-9 value >100 U/mL, number of CRLM 5-, and nonlaparoscopic approach were selected as that of RFS. Despite having a higher prevalence of advanced stage CRLM in the 2013-2017 patient population compared to the 2005-2007 cohort, prognostic outcomes demonstrably improved in the later period.