Combination Chemotherapy and Radiation Therapy in Treating Patients With Pancreatic Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed pancreatic adenocarcinoma * Non-metastatic disease that is unresectable due to any of the following: * Tumor greater than 5 cm * Bulky lymph nodes greater than 2 cm, but within the radiation port * Vascular involvement or impingement of major vessels * Involvement of colon, adrenal glands, or kidney * Measurable or evaluable disease * No prior therapy for pancreatic adenocarcinoma * No peritoneal seeding or other evidence of metastatic disease by laparotomy or laparoscopy PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * CTC 0-2 Life expectancy: * Not specified Hematopoietic: * WBC at least 3,000/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Bilirubin no greater than 2.0 mg/dL * AST no greater than 3 times upper limit of normal Renal: * Creatinine no greater than 2.0 mg/dL Cardiovascular: * No myocardial infarction within the past 6 months Other: * No other uncontrolled serious medical or psychiatric illness that would preclude study compliance * No other malignancy within the past 5 years except limited or curatively treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * See Disease Characteristics Chemotherapy: * See Disease Characteristics Endocrine therapy: * See Disease Characteristics Radiotherapy: * No prior abdominal radiotherapy Surgery: * At least 2 weeks since prior major surgery