S0202 Gemcitabine and Capecitabine for Unresectable Locally Advanced Metastatic Gallbladder Cancer or Cholangiocarcinoma

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed gallbladder cancer or cholangiocarcinoma * Locally advanced or metastatic disease that is unresectable * Eligible subtypes: * Adenocarcinoma, intestinal type * Adenocarcinoma, not otherwise specified (NOS) * Papillary carcinoma * Clear cell adenocarcinoma * Mucinous carcinoma * Signet ring cell carcinoma * Squamous cell carcinoma * Adenosquamous carcinoma * Small cell carcinoma * Undifferentiated carcinoma * Carcinoma, NOS OR * Histologically confirmed adenocarcinoma of a metastatic site with clinical documentation\* of gallbladder or bile duct involvement and no evidence of another primary NOTE: \*If clinical documentation of gallbladder or bile duct involvement is not possible due to removal of the organ, a clinically and/or radiographically consistent picture plus pathologic findings from the metastatic site consistent with cholangiocarcinoma are allowed * Measurable disease located outside prior radiotherapy port * No carcinoid tumors or sarcomas PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * Zubrod 0-2 Life expectancy: * Not specified Hematopoietic: * Absolute granulocyte count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Bilirubin no greater than 3 times upper limit of normal (ULN) * Serum glutamic oxaloacetic transaminase (SGOT) or Serum glutamic pyruvic transaminase (SGPT) no greater than 2…