Adjuvant radiation therapy after axillary lymphadenectomy for metastatic melanoma: toxicity and local control

Certain patients with locally advanced melanoma have a high risk of regional recurrence after surgical excision and lymphadenectomy alone. Growing evidence suggests that radiation therapy may improve local control with acceptable morbidity for patients with melanoma in some sites. There is no information regarding the safety or efficacy of this treatment when applied to the axilla for regional metastasis of cutaneous melanoma.

We conducted a retrospective evaluation of patients who received postoperative radiation therapy to the axillary lymphatics for malignant melanoma at the M. D. Anderson Cancer Center between 1980 and 1992. Twenty-eight patients were identified who had undergone a formal axillary lymph node dissection followed by postoperative irradiation to the full axilla and supraclavicular fossa. Twenty-two patients were irradiated using a hypofractionated treatment regimen (4-7 Gy/fraction), generally to 30 Gy in five fractions.

Sixteen patients are currently alive. Actuarial survival at 5 years is 50.1%. Local tumor recurred or persisted in five patients, four of whom had clinically palpable tumor when they were irradiated.

Postoperative irradiation of the axilla for malignant melanoma has acceptable toxicity, even in those with extensive axillary dissection. In this group, patients treated for subclinical disease had a low rate of recurrence (1 of 21, [5%]).