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