Gemcitabine With or Without Cisplatin in Treating Patients With Unresectable Locally Advanced or Metastatic Cholangiocarcinoma or Other Biliary Tract Tumors (ABC-02)

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed biliary tract, gallbladder, or ampullary carcinoma Intra- or extra-hepatic disease allowed Unresectable locally advanced, recurrent, or metastatic disease No brain metastases PATIENT CHARACTERISTICS: Performance status ECOG 0-2 Life expectancy At least 3 months Hematopoietic Absolute neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 Hemoglobin ≥ 10 g/dL (transfusion allowed) WBC ≥ 3,000/mm^3 Hepatic AST and ALT ≤ 3 times upper limit of normal (ULN) (5 times ULN if liver metastases are present) Bilirubin ≤ 1.5 times ULN Alkaline phosphatase ≤ 3 times ULN (5 times ULN if liver metastases are present) Adequate biliary drainage No unresolved biliary tract obstruction Renal Creatinine < 1.5 times ULN Urea < 1.5 times ULN Glomerular filtration rate (GFR) ≥ 45 mL/min If GFR < 60 mL/min, isotope EDTA confirmation of adequate renal function is required Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 3 months after study participation No active, uncontrolled infection No other severe or uncontrolled systemic disease No other malignancy within the past 5 years except nonmetastatic basal cell or squamous cell skin cancer or carcinoma in situ of the cervix treated by cone-biopsy or resection No psychiatric disorder that would preclude giving informed consent PRIOR CONCURRENT THERAPY: Chemotherapy At least 6 months since prior adjuvant chemotherapy No prior gemcitabine hydrochloride No prior cisplatin No prior systemic chemotherapy for locally advanced or metastatic disease except low-dose radiosensitizing chemotherapy in conjunction with radiotherapy Radiotherapy Prior radiotherapy for localized disease allowed provided there is clear evidence of disease progression afterwards Surgery Prior curative surgery allowed provided there is evidence of nonresectable disease relapse requiring systemic chemotherapy Other Recovered from all prior therapies Prior photodynamic therapy (PDT) allowed provided it was given for localized disease only (with no evidence of metastatic disease) and resulted in subsequent disease progression after completion of therapy OR to relieve biliary obstruction in the presence of metastatic disease PDT must have been completed ≥ 4 weeks ago At least 4 weeks since prior investigational agents No other concurrent, curative anticancer therapy