Worldwide, colorectal cancer is responsible for 1,400,000 new cases and more than 600,000 deaths each year, the third most common neoplasm, and its incidence is increasing [1]. Overall, approximately 20% of patients have synchronous colorectal liver metastases (CRLM) at presentation, and a further 40%–50% develop metachronous CRLM after primary lesion resection [2]. Hepatic resection is the only treatment that can provide the possibility of prolonged survival or even cure for patients with CRLM. It is associated with a 5-year survival rate of ranging from 30% to 50% [3,4].

Reliable prognostic indicators after hepatectomy for CRLM are important for improving the prognosis. Beppu et al. [5] reported that prognostic tumor factors include synchronous metastases, positive primary lymph node, tumor number, tumor size, extrahepatic metastatic disease, and the carbohydrate antigen 19-9 (CA19-9) level. However, additional reliable prognostic factors are needed because of the heterogeneity of the prognosis even among patients with the same tumor factors.

Increasing evidence has demonstrated that systemic inflammatory response markers such as the Glasgow Prognostic Score (GPS) and prognostic nutritional index (PNI) predict cancer-specific survival in various cancers, including CRLM [6,7]. The GPS includes albumin (Alb) and C-reactive protein (CRP), and the PNI includes Alb and lymphocytes.

The CRP–Alb–lymphocyte (CALLY) index was developed as a novel immunonutritional scoring system by Müller et al. [8]. The CALLY index has been associated with both recurrence-free survival and overall survival (OS) and was found to be superior to other inflammation-based biomarkers in patients with hepatocellular carcinoma who underwent hepatectomy [9]. However, the prognostic value of the CALLY index in patients with CRLM who have undergone hepatectomy has not been explored.

This study was performed to investigate the impact of the preoperative CALLY index on the outcomes of patients with CRLM after hepatic resection in conjunction with other nutritional markers, including the GPS and PNI.