OBJECTIVES: Colorectal cancer (CRC) is the second most commonly diagnosed cancer and the third cause of cancer-related mortality in Taiwan. Capecitabine (Xeloda®), an oral fluoropyrimidine, is an effective alternative to intravenous fluorouracil plus leucovorin (5-FU/LV) in treatment of metastasis colon cancer (mCRC). Recently, the addition of oxaliplatin to 5-FU/LV (FOLFOX) or capecitabine (XELOX) have been proven in significantly improving the progression free survival and overall survival compared with single agent. Based on the result of study NO16966 (Cassidy 2007), there is no difference in efficacy between XELOX and FOLFOX. The objective of this study was to develop a pharmacoeconomic model to estimate the medical resource utilization (MRU) of XELOX vs. FOLFOX as first line treatment of mCRC from the payer's [Bureau of National Health Insurance (BNHI)] perspective. METHODS: A cost-minimization model was constructed to represent the real MRU of XELOX and FOLFOX. Local treatment regimens and drugs administration patterns were based on the results of expert panel survey conducted among 13 colorectal surgeons and medical oncologists. Clinical outcomes and adverse events (AEs) incidence were referred to the result of study NO16996. Unit costs were estimated from BNHI fee schedules and local expert opinion. Sensitivity analyses were performed on key model parameters. RESULTS: The result showed drug cost was estimated to be higher in the XELOX (NTD$259,618 vs. NTD$204,442) by 6 months. However, these cost increments were offset by the drug administration cost and AEs management cost of FOLFOX. The drug administration cost and AEs management cost in the FOLFOX and XELOX were NTD$119,285 vs. NTD$24,090 and NTD$14,414 vs. NTD$7,155, respectively. FOLFOX regimen required more physician visits, drug infusion times and hospitalizations. As a result, XELOX demonstrated a significant overall cost savings of NTD$47,277. CONCLUSIONS: From the perspective of Taiwan BNHI, this study showed that XELOX is cost-saving in comparison with FOLFOX in the first line treatment of mCRC