The type of liver resection (anatomical resection, AR or nonanatomical resection, NAR) for colorectal liver metastases (CRLM) is subject to debate. The debate may persist because some certain prognostic factors, associated with aggressive biological behavior of tumor, have been overlooked. The aim of our study was to investigate the characteristics of patients who would benefit more from anatomical resection for colorectal liver metastases.

729 patients who underwent hepatic resection of CRLM were retrospectively collected from June 2012and May 2019. Treatment effects between AR and NAR were compared in full subgroup analyses. Tumor relapse-free survival (RFS) was evaluated by a stratified log-rank test and summarized with the use of Kaplan-Meier and Cox proportional hazards methods.

Inclusion Criteria:

(1)Age 18-79 years;(2) Histologically proven colorectal adenocarcinoma;

Exclusion Criteria:

(1) the histologic type of tumor was not called adenocarcinoma; (2) peritoneal metastasis; (3) number of liver metastasis >3; (4) simultaneous anatomical and nonanatomical resections; (5) R2 resection; (6) history of previous hepatectomy; (7) incomplete data. The rest of patients were divided into 2 groups: patients undergoing an AR, and patients undergoing a NAR.

The study was a retrospective cohort study based on our prospectively collected colorectal cancer database. All adult patients who underwent curative-intent liver resection for CRLM between June 2012 and May 2019 at Zhongshan Hospital in Shanghai and had available data on KRAS/NRAS/BRAF status, were eligible for inclusion.