RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. It is not yet known if radiation therapy combined with chemotherapy kills more tumor cells than radiation therapy alone in treating cancer of the vulva.

PURPOSE: Randomized phase III trial to determine the effectiveness of radiation therapy with or without cisplatin in treating patients who have stage I, stage II, or stage III cancer of the vulva.

OBJECTIVES:

• Compare the recurrence-free interval and survival in patients with stage I, II, III, or IVA squamous cell carcinoma of the vulva with involved inguinal lymph nodes treated with adjuvant radiotherapy with or without cisplatin.
• Compare the toxicity of these regimens in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to primary surgical resection (yes vs no) and node status (N1 vs N2).

Patients are randomized to one of two treatment arms.

• Arm I: Patients undergo radiotherapy 5 days a week for 6 weeks.
• Arm II: Patients undergo radiotherapy as in arm I. Patients also receive cisplatin IV over 1 hour on days 1, 8, 15, 22, 29, and 36.

Patients are followed every 3 months for 2 years and then every 6 months for 3 years.

PROJECTED ACCRUAL: A total of 250 patients will be accrued for this study within 4.5 years.

• Drug: cisplatin
• Radiation: radiation therapy

DISEASE CHARACTERISTICS:

• Histologically confirmed stage I, II, III, or IVA squamous cell carcinoma of the vulva amenable to curative treatment with surgery, radiotherapy, or both

  • At least 1 positive inguinal and/or femoral lymph node
  • No inoperable (fixed or ulcerating) groin nodes
  • Must not require resection of urethra or anal sphincter to achieve negative margins
• Must have undergone vulvar biopsy and bilateral inguinal/femoral lymph node dissection within 8 weeks of randomization
• No metastatic disease

PATIENT CHARACTERISTICS:

Age:

• Any age

Performance status:

• GOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• WBC at least 3,000/mm^3
• Platelet count at least 100,000/mm^3
• Granulocyte count at least 1,500/mm^3

Hepatic:

• Bilirubin no greater than 1.5 times normal
• SGOT no greater than 3 times normal
• Alkaline phosphatase no greater than 3 times normal

Renal:

• Creatinine no greater than 2.0 mg/dL

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No other prior invasive malignancy within the past 5 years except nonmelanoma skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy

Endocrine therapy:

• Not specified

Radiotherapy:

• See Disease Characteristics
• No prior radiotherapy

Surgery:

• See Disease Characteristics
• No more than 8 weeks since prior surgery

Other:

• No prior therapy for another malignancy that would preclude study