DISEASE CHARACTERISTICS:

• Diagnosis of neuroendocrine tumor of the duodenum/pancreas by histology or bone scan

• Functional or nonfunctional tumor

  • Tumor meets ≥ 1 of the following criteria:

    • Hepatic or extrahepatic metastases
    • Progressive locally advanced tumor (primary or adenopathies)
• Unresectable disease

• Tumor differentiated and meets the following criteria:

  • Ki 67 ≤ 15%
  • Less than 10 mitoses per 10 large fields

• Measurable or evaluable disease

  • Target lesions must meet 1 of the following criteria within the past 6 months:

    • Increase of 20% in the longest diameter
    • New metastases detected

  • Minimum size of lesions must be 1 of the following:

    • More than 15 mm for metastases
    • More than 50 mm for primary tumor or local lymph nodes

PATIENT CHARACTERISTICS:

• WHO performance status 0-2
• Creatinine ≤ 1.5 mg/dL
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Bilirubin ≤ 1.8 mg/dL
• No coronary insufficiency or symptomatic cardiac disease
• No intestinal obstruction, enteropathy, or uncontrolled chronic diarrhea
• No Gilbert's disease
• No psychological, social, familial, or geographic condition that would preclude study treatment
• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 6 months after completion of study therapy
• No other condition that would preclude study therapy

PRIOR CONCURRENT THERAPY:

• No prior adjuvant radiotherapy
• At least 3 months since prior interferon
• Prior somatostatin analogs or antisecretories allowed
• No other prior treatment for this cancer
• No concurrent radiotherapy to the target lesion