Background   About 50% of patients with colorectal cancer may develop colorectal liver metastases (CLM) during the course of the disease, and their prognosis are often poor. Simultaneous liver resection according to the anatomical location of liver metastases can improve the prognosis of CLM patients.

  Objective   To investigate the clinical features and prognostic factors of CLM patients.

  Methods   A retrospective analysis was performed on patients diagnosed with synchronous liver metastasis of colorectal cancer and underwent simultaneous radical resection surgery in the First Medical Center of Chinese PLA General Hospital from April 2015 to March 2019. Relevant clinical, pathological data of primary and metastatic tumor were collected, and patients with CLM were followed up. According to the location of liver metastasis, patients were divided into unilateral liver metastasis group and bilateral liver metastasis group. Univariate analysis and Cox regression were used to analyze the independent factors influencing postoperative prognosis of patients with CLM, and Kaplan-Meier curves were drawn to compare the overall survival (OS) of patients.

  Results   A total of 157 eligible patients were included, including 100 males and 57 females, with age ranging from 31 to 82 years. According to the location of metastasis, patients were divided into unilateral liver metastasis group and bilateral liver metastasis group. Propensity score matching method was used to match the two groups, and a total of 31 groups were successfully matched. The proportion of liver metastases > 3 in bilateral liver metastasis group was significantly higher than that in unilateral liver metastasis group (51.6% vs 9.7%, P < 0.05), the OS (19.0013.0-37.0 vs 38.0020.0-48.0) and 3-year survival rate (29.0% vs 54.8%) were significantly lower than those in unilateral liver metastasis group (P < 0.05). Univariate analysis showed that primary tumor located in the right colon, poorly differentiated primary tumor, bilateral liver metastasis, the number of liver metastases > 3, preoperative CEA > 10 ng/mL had significant effects on the prognosis of CLM patients (P < 0.05). Multivariate analysis showed that primary tumor located in the right colon (HR=4.067, 95% CI: 1.738-9.516, P=0.001), poorly differentiated (HR=2.482, 95% CI: 1.280-4.812, P=0.007), bilateral liver metastases (HR=2.263, 95% CI: 1.008-5.079, P=0.048), preoperative CEA > 10 ng/mL (HR=2.230, 95% CI: 1.048-4.747, P=0.037) and preoperative CA199 > 27 ng/mL (HR=2.049, 95% CI: 1.008-4.166, P=0.048) were all risk factors affecting prognosis.

  Conclusion   CLM patients with bilateral liver metastases have more liver metastases, lower OS and 3-year survival. The primary tumor located in the right colon, poorly differentiated of primary tumor, bilateral liver metastasis, preoperative CEA > 10 ng/mL, and preoperative CA199 > 27 ng/mL are related risk factors affecting the prognosis of CLM patients.