OBJECTIVES: This study aimed to investigate if the addition of bevacizumab to CAPOX/FOFLOX4 was cost-effective as a first-line treatment of MCRC in Hong Kong. METHODS: This was a retrospective observational study conducted in two public hospitals in Hong Kong. Patients received either CAPOX or FOLFOX4 with or without bevacizumab from Jan 2011 to Dec 2014 as first-line treatment were included. Direct medical costs were estimated based on Hong Kong Gazette and internal systems in both hospitals. Cost analysis was performed from the healthcare-payer perspective. All costs were expressed in Hong Kong dollar (1US$=7.8HK$) and 2014 was the base year. QALY were calculated by the product of utility scores from previous literature and PFSD from the medical records. Probabilistic sensitivity analysis was conducted to estimate the most cost-effective treatment. RESULTS: A total of 105 patients were included. Base case analysis revealed that the total cost for CAPOX and CAPOX with bevacizumab were HKD103,961.35 and HKD180,386.56 respectively while the PFSD were 155.5 days and 199.5 days. The total cost of FOLFOX4 was HKD137,105.81 and HKD322,608.76 for FOLFOX4 with bevacizumab whereas the PFSD is 85 days and 259.5 days respectively. The ICER is HKD1,074,545/QALY when comparing CAPOX with or without bevacizumab and HKD732,103/QALY for FOLFOX4 counterpart. PSA revealed that there are a 28% and 22% chance for bevacizumab to be cost effective when added to CAPOX and FOLFOX4 respectively at a willingness-to-pay of HKD935,505, which is three times the GDP per capita of Hong Kong in 2014. CONCLUSIONS: The current study demonstrated that adding bevacizumab to FOLFOX4 was cost-effective but not to CAPOX. However, further studies are required in view of the different limitations encountered in the current study.