The combination of 5-FU or it's oral analog capecitabine and gemcitabine chemotherapy alone (without radiation) in the advanced metastatic setting has improved response rates and median overall survivals from around 10% or 6.1 months to 10-36% and 9.7 to 14 months respectively.13a Based on this data it likely should have synergy if both agents are given concurrently with external beam RT. The combination of continuous 5-FU and gemcitabine with external beam radiation in locally advanced pancreatic cancer has been shown to be safe and resulted in a complete response in 2 patients (6.3%), a partial response in 18 patients (56.3%), with an overall all response rate of 62.5% 13b. Based on this data and the similar dose of external RT therapy it seems reasonable and safe to combine the two agents 5-FU and gemcitabine with RT in advanced cholangiocarcinoma. We chose to use 5-FU rather than oral capecitabine due to occasional problems obtaining prescription coverage for this more expensive alternative and the prior available safety data and our own institutional experience using 5-FU and gemcitabine combination with RT for pancreatic cancer.