RATIONALE: Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop tumor cells from dividing so they stop growing or die. Anticoagulants such as dalteparin may help prevent blood clots in patients being treated with gemcitabine for unresectable or metastatic pancreatic cancer.

PURPOSE: Randomized phase III trial to compare the effectiveness of gemcitabine with or without dalteparin in treating patients who have unresectable or metastatic pancreatic cancer.

OBJECTIVES:

• Compare the quality of life of patients with unresectable or metastatic pancreatic cancer treated with gemcitabine with or without dalteparin.
• Compare the survival of patients treated with these regimens.
• Compare the incidence of venous thromboembolic complications in patients treated with these regimens.
• Determine the safety of dalteparin, in terms of bleeding complications, in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to disease stage (unresectable nonmetastatic vs metastatic). Patients are randomized to one of two treatment arms.

• Arm I: Patients receive gemcitabine IV over 30 minutes once weekly on weeks 1-7 for the first course only. Beginning on week 9, patients receive gemcitabine IV over 30 minutes once weekly for 3 weeks. Treatment then repeats every 4 weeks for up to 6 months in the absence of unacceptable toxicity or disease progression.
• Arm II: Patients receive gemcitabine as in arm I and dalteparin subcutaneously once daily for 6 months in the absence of unacceptable toxicity.

Quality of life is assessed at baseline and every 4 weeks during study therapy.

Patients are followed every 4 weeks.

PROJECTED ACCRUAL: A total of 400 patients (200 per treatment arm) will be accrued for this study within 40 months.

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed pancreatic adenocarcinoma or poorly differentiated carcinoma of the pancreas that is considered ineligible for curative resection

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• WBC greater than 3,500/mm^3
• Platelet count greater than 100,000/mm^3
• No clinically significant bleeding disorder
• No prior heparin-induced thrombocytopenia

Hepatic:

• Bilirubin less than 2.0 mg/dL
• AST less than 3 times normal

Renal:

• Creatinine less than 2.0 mg/dL

Cardiovascular:

• No prior hemorrhagic stroke
• No uncontrolled hypertension (sustained blood pressure greater than 200 mm Hg systolic or 110 mm Hg diastolic)

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No other active malignancy
• No gastrointestinal bleeding within the past 30 days
• No contraindications to anticoagulation

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy for metastatic disease
• Prior adjuvant chemotherapy allowed

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• Prior surgical resection allowed
• At least 4 weeks since prior surgery with non-curative intent and recovered
• More than 30 days since prior neurologic or ophthalmologic surgery

Other:

• At least 2 weeks since prior low-molecular-weight heparin
• More than 30 days since prior experimental therapeutic agent
• No concurrent heparin or warfarin for pre-existing condition