RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Interferon alfa-2b may interfere with the growth of cancer cells. It is not yet known whether giving radiation therapy with interferon alfa-2b is more effective than giving interferon alfa-2b alone in treating melanoma.

PURPOSE: Randomized phase III trial to compare the effectiveness of radiation therapy plus interferon alfa-2b with that of interferon alfa-2b alone in treating patients who have melanoma that has metastasized to lymph nodes in the neck, under the arm, or in the groin.

OBJECTIVES: I. Evaluate the effectiveness of postoperative hypofractionated radiotherapy in combination with high dose interferon in preventing regional relapse in patients with malignant melanoma with any number of nodes with clinical extracapsular extension or previous nodal basin recurrence. II. Evaluate the effectiveness of this therapy in prolonging relapse free and overall survival in this patient population. III. Evaluate the toxicity of this therapy in this patient population.

OUTLINE: This is a randomized study. Patients are stratified according to prior nodal basin recurrence, site of disease, and extracapsular extension. Following surgery, patients are randomized to receive either interferon alfa-2b alone or five treatments of radiotherapy followed by interferon alfa-2b. Patients receive radiotherapy 2 days a week for 2.5 weeks. Patients receive interferon alfa-2b IV over 20 minutes daily for 5 days for a total of 28 days, followed by subcutaneous injections 3 times a week for 48 weeks. Patients are followed every 3 months for 2 years, then every 6 months for 3 years, then annually thereafter.

PROJECTED ACCRUAL: Approximately 167 patients will be accrued for this study within 3 years.

DISEASE CHARACTERISTICS: Histologically documented malignant melanoma in node(s) meeting one or more of the following criteria: 1 or more lymph nodes found to contain metastatic melanoma with gross evidence of extracapsular nodal extension Nodal recurrence at the site of previous lymphadenectomy All gross cancer removed with negative margins Prior node biopsy allowed if complete nodal dissection performed Parotid involvement outside a node allowed No distant metastases

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm3 Platelet count at least 125,000/mm3 Hematocrit at least 33% Hepatic: AST no greater than 2 times upper limit of normal (ULN) LDH no greater than 2 times ULN Alkaline phosphatase no greater than 2 times ULN Bilirubin no greater than 2 times ULN If LDH or alkaline phosphatase are above normal, CT or MRI of liver required Renal: Creatinine no greater than 1.8 mg/dL BUN no greater than 33 mg/dL Other: Not pregnant or nursing Fertile patients must use effective contraception No other prior or concurrent malignancies within 2 years, except any carcinoma in situ, lobular carcinoma of the breast in situ, carcinoma in situ of the cervix, atypical melanocytic hyperplasia or Clark I melanoma in situ, or basal or squamous cell skin cancer

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior interferon Chemotherapy: Not specified Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to the head and neck, axillary, or inguinal areas Surgery: See Disease Characteristics Recovered from prior surgery