RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining chemotherapy with radiation therapy before surgery may shrink the tumor so that it can be removed during surgery.

PURPOSE: Randomized phase II trial to compare the effectiveness of two different regimens combining chemotherapy with radiation therapy in treating patients who are undergoing surgery for locally advanced pancreatic cancer.

OBJECTIVES:

• Compare the percentage of margin-free resections in patients with locally advanced, potentially resectable adenocarcinoma of the pancreas treated with gemcitabine and radiotherapy vs gemcitabine, fluorouracil, and cisplatin followed by radiotherapy and fluorouracil.
• Compare the efficacy of these regimens, as measured by CT scan response, in these patients.
• Compare the posttreatment fibrosis in resected specimens of patients treated with these regimens.
• Compare the toxicity of these regimens in these patients.
• Compare the duration of objective response in patients treated with these regimens.
• Compare the disease-free and overall survival of patients treated with these regimens.
• Compare the effect of these regimens and disease recurrence on CA 19-9 values in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to superior mesenteric vein (SMV)/portal vein (PV) occlusion (yes vs no), SMV/PV/superior mesenteric artery/hepatic artery abutment or narrowing (yes vs no), prior exploration (yes vs no), and whether deemed to require preoperative therapy due to other factors (yes vs no). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo radiotherapy once daily 5 days a week for 6 weeks. Patients receive gemcitabine IV over 50 minutes once weekly for 6 weeks during radiotherapy. Patients undergo surgical resection 4-6 weeks after completion of chemoradiotherapy.

Maintenance therapy (4-8 weeks after completion of surgery): Patients receive gemcitabine IV over 100 minutes once weekly for 2 weeks. Treatment repeats every 3 weeks for 5 courses in the absence of disease progression or unacceptable toxicity.

• Arm II: Patients receive gemcitabine IV over 30 minutes on days 1, 5, 29, and 33; cisplatin IV over 60 minutes on days 1-5 and 29-33; and fluorouracil IV continuously on days 1-4 and 29-32. Patients also receive filgrastim (G-CSF) subcutaneously (SC) daily on days 6-15 and 34-43 and epoetin alfa SC weekly on weeks 1-9. After completion of chemotherapy, patients undergo radiotherapy once daily 5 days a week for 6 weeks. Patients receive fluorouracil IV continuously daily during radiotherapy. Patients undergo surgical resection 4-6 weeks after completion of chemoradiotherapy.

Maintenance therapy (4-8 weeks after completion of surgery): Patients receive gemcitabine IV over 100 minutes once weekly for 2 weeks. Treatment repeats every 3 weeks for 3 courses in the absence of disease progression or unacceptable toxicity.

Patients are followed every 3 months for 2 years and then every 6 months for 2 years.

PROJECTED ACCRUAL: A total of 80-160 patients (40-80 per treatment arm) will be accrued for this study.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the pancreas

  • No adenosquamous cancers or adenocarcinoma associated with cystic mucinous neoplasms
  • Locally advanced disease that is potentially resectable, previously explored and considered unresectable, or deemed to require preoperative treatment for other reasons
  • Primary cancer in the head, body, or tail of pancreas

• Measurable disease

• No 360 degree encirclement of the superior mesenteric artery, hepatic artery, or celiac axis

• No metastases by CT scan and laparoscopy (if prior surgery, only CT scan required)

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Absolute granulocyte count greater than 2,000/mm^3
• Platelet count greater than 100,000/mm^3

Hepatic

• Bilirubin less than 2 mg/dL (unless secondary to bile duct blockage by tumor)
• Biliary obstruction by tumor requires biliary stent at least 9 French or biliary bypass before therapy

Renal

• Creatinine less than 1.7 mg/dL OR
• Creatinine clearance greater than 60 mL/min

Other

• No other malignancy within the past 3 years except nonmelanoma skin cancer
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No prior chemotherapy for this disease

Endocrine therapy

• Not specified

Radiotherapy

• No prior radiotherapy to pancreas

Surgery

• Not specified