Objective:The combination of hepatic arterial chemotherapy (HAIC) and systemic chemotherapy (SYC) has potential ef ect on colorectal cancer (CRC) patients with unresectable hepatic metastasis. The aim of this retrospective study was to investigate the ef icacy and safety of this combined therapeutic regimen on Chinese patients based on single institute experiences. Methods:Al 54 patients of this retrospective analysis were diagnosed with CRC with unresectable liver metas-tasis and received combined HAIC and SYC. Among the patients, 23 of them received HAIC plus SYC when they developed liver metastases as first-line treatment (Group 1), and 31 patients received HAIC plus SYC as non-first-line treatment (Group 2). The dif erent ef icacy in two groups was analyzed by SPSS 19.0. Results:The overal response rate (ORR) were 52.2%and 25.8%respectively in Groups 1 and 2 (P=0.047), and the disease control rate (DCR) were 65.2%and 35.5%respec-tively in Groups 1 and 2 (P=0.031). The median progression-free survival (PFS) were 6.8 and 3.3 months (P=0.002), the median hepatic progression-free survival (H-PFS) were 8.8 and 3.7 months (P=0.001), and the median overal survival (OS) were 18.8 and 13.7 months (P=0.121) in Groups 1 and 2, respectively. No fatal reaction was observed and no significant dif erence of adverse reaction was found in two groups. Grade 3/4 toxic ef ects included neutropenia (9.7%in Group 2 only), gastrointestinal reaction (8.7%in Group 1 and 6.5%in Group 2), stomatitis (6.5%in Group 2 only) and hyperbilirubinemia (4.3%in Group 1 only). Conclusion:HAIC combined with SYC showed promising ef icacy and safe profiles on CRC patients with unresectable liver metastases.