Fluorouracil Plus Interferon Alfa in Treating Patients With Advanced Metastatic Carcinoid Tumors

DISEASE CHARACTERISTICS: Histologically proven carcinoid tumor with radiologically confirmed metastatic disease Recurrence after surgery or radiotherapy allowed Must meet at least 1 of the following conditions: Symptomatic carcinoid syndrome not controlled Other systemic symptoms (e.g., weight loss, anorexia) 24 hour urinary 5-hydroxyindole acetic acid (5-HIAA) 100 mg or greater Bone metastases Carcinoid heart disease Carcinoid asthma Measurable disease or 24-hour urinary 5-HIAA 50 mg or greater required No known brain metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-2 Hematopoietic: Granulocyte count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin no greater than 3.0 mg/dL Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: See Disease Characteristics Pulmonary: See Disease Characteristics Other: No concurrent infection (no fever for at least 3 days prior to treatment unless fever due to tumor) No significant medical or psychiatric illness that would preclude study or informed consent No other malignancy within the past 5 years except basal cell or squamous cell skin cancer or curatively treated stage I carcinoma of the cervix Not pregnant Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: No prior interferon therapy Chemotherapy: No other concurrent chemotherapy Endocrine therapy: Prior endocrine therapy allowed Concurrent octreotide allowed Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy No concurrent radiotherapy Surgery: See Disease Characteristics Prior surgery allowed Other: No prior fluorinated pyrimidine