RATIONALE: Drugs used in chemotherapy, such as gemcitabine hydrochloride and oxaliplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Observation is watching a patient's condition but not giving treatment until symptoms appear. It is not yet known whether giving gemcitabine hydrochloride together with oxaliplatin is more effective than observation in treating patients with biliary tract cancer that has been removed by surgery.

PURPOSE: This randomized phase III trial is studying giving gemcitabine hydrochloride together with oxaliplatin to see how well it works compared with observation in treating patients with biliary tract cancer that has been removed by surgery.

OBJECTIVES:

Primary

• Compare disease-free survival (DFS) of patients with resected biliary tract cancer treated with adjuvant gemcitabine hydrochloride and oxaliplatin versus clinical observation.
• Compare quality of life of these patients.

Secondary

• Compare overall survival of these patients.
• Determine the toxicity of the chemotherapy in these patients.
• Explore prognostic factors for DFS including resection result (R0 vs R1), location of primary tumor (intrahepatic vs extrahepatic vs gallbladder), evolution of CA19-9, and lymph node involvement (N0 vs N+ and Nx). (Exploratory)
• Study pathological factors in surgical specimens to identify main characteristics and phenotypic clinicoanatomical biliary tract cancers before therapy. (Exploratory)
• Identify nontumor-associated liver injury and factors that may facilitate the emergence of biliary tract cancers. (Exploratory)
• Identify signaling pathways that may predict response to therapy. (Exploratory)
• Determine the molecular characteristics to differentiate tumors according to their position in the biliary tract (extrahepatic bile duct, intrahepatic cholangiocarcinoma site [hilar], and peripheral cholangiocarcinoma vesicle site). (Exploratory)

OUTLINE: This is a multicenter study. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive gemcitabine hydrochloride IV over 100 minutes on day 1 and oxaliplatin IV over 2 hours on day 2. Treatment repeats every 14 days for 12 courses.
• Arm II: Patients undergo clinical observation only every 4 weeks for 5 months. Quality of life is assessed at baseline, at 3 and 6 months, and then at all follow-up visits.

After completion of study therapy, patients are followed up at 6 months, every 3 months for 2 years, and then every 6 months for 3 years.

DISEASE CHARACTERISTICS:

• Histologically proven adenocarcinoma of the intrahepatic bile ducts, gallbladder, or extrahepatic bile ducts

  • Mixed forms of hepatocholangiocarcinomas included provided the cholangiocarcinoma is predominant

• Underwent surgical resection of the disease (R0 or R1) at least 4 weeks but no more than 13 weeks ago

• Nonmetastatic disease as assessed by abdominal MRI and chest x-ray

• No cancer of the pancreas or duodenum invading the bile duct and ampulla of Vater

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Hemoglobin ≥ 10 g/dL (transfusion allowed)
• ANC ≥ 1,500/mm³
• Platelet count ≥ 75,000/mm³
• Creatinine clearance > 40 mL/min
• Prothrombin time > 60% OR INR < 1.5 (without anticoagulant therapy)
• Transaminases ≤ 5 times upper limit of normal (ULN)
• Alkaline phosphatase ≤ 2.5 times ULN
• Conjugated bilirubin ≤ 35 μmol/L (after biliary drainage, if necessary)
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No contraindications to oxaliplatin and gemcitabine hydrochloride therapy
• Prior invasive cancer allowed provided it has been in complete remission for ≥ 5 years
• No other concurrent invasive cancer except adequately treated carcinoma in situ of the cervix or basal cell carcinoma
• No other severe, unresolved disease
• No mental illness
• No HIV positivity
• No grade 1 angina or symptomatic angina ≥ grade 2
• No sensitive peripheral neuropathy
• No uncontrolled diabetes
• No inability to undergo medical tests due to geographical, social, or psychological reasons
• No prisoners or patients under guardianship
• No Child B or C cirrhosis

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior neoadjuvant chemotherapy or radiotherapy
• No prior organ transplantation
• No concurrent participation in another clinical trial of an experimental agent