Interferon Alfa Following Surgery in Treating Patients With Stage III Melanoma

DISEASE CHARACTERISTICS: * Histologically confirmed previously resected stage III primary cutaneous melanoma or unknown primary with regional lymph node involvement * N1 disease * Microscopic, nonpalpable nodal involvement * Primary melanoma of any stage with clinically inapparent N1 regional lymph node metastases (T1-4, N1, M0) detected by elective lymph node dissection or sentinel node biopsy * N2 disease * Palpable nodal involvement with synchronous primary melanoma or apparent nodal disease after prior excision (any pT, N2, M0) * Regional lymph node recurrence at any interval after surgery for primary melanoma of any depth (T1-4, rN2, M0) * Complete resection of primary melanoma with adequate surgical margins * Full lymphadenectomy must be performed within 70 days of study * No mucous membrane melanoma or ocular melanoma * No evidence of distant or nonregional lymph node metastases or in transit metastases (even if previously resected) * No incompletely resected disease due to gross extracapsular extension PATIENT CHARACTERISTICS: Age: * 18 to 70 Performance status: * ECOG 0-1 Life expectancy: * Not specified Hematopoietic: * WBC at least 3,000/mm\^3 * Platelet count greater than 100,000/mm\^3 * Hemoglobin at least 9 g/dL Hepatic: * SGOT and SGPT less than 2 times upper limit of normal * No active hepatitis Renal: * Creatinine less than 2.0 mg/dL Cardiovascular: * No severe cardiovascular disease including the following: * Arrhythmias requiring chronic treatment * Congestive heart failure (New York Heart Association class III or IV) * Symptomatic ischemic heart disease Other: * No other prior malignancy within the past 5 years except surgically cured nonmelanomatous skin cancer or carcinoma in situ of the cervix * No thyroid dysfunction unresponsive to therapy * No uncontrolled diabetes mellitus * No active autoimmune disease * No active and/or uncontrolled infection * No history of neuropsychiatric disorder requiring hospitalization * No known active alcohol or drug abuse * HIV negative * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * No prior interferon alfa * No prior immunotherapy for melanoma * No other concurrent immunologic or biologic therapy * No concurrent colony stimulating factors including epoetin alfa and filgrastim (G-CSF) Chemotherapy: * No prior chemotherapy for melanoma * No concurrent chemotherapy Endocrine therapy: * No prior hormonal therapy for melanoma * No concurrent hormonal therapy * No concurrent chronic systemic corticosteroid therapy Radiotherapy: * No prior radiotherapy for melanoma * No concurrent radiotherapy Surgery: * See Disease Characteristics * Recovered from any prior recent surgery Other: * At least 30 days since other prior experimental therapy * No other concurrent investigational drugs