Elective radiation therapy for high-risk malignant melanomas

Local-regional recurrence rates of 30%-50% have been reported after resection of high-risk malignant melanomas (multiple node involvement, extracapsular spread, deep invasion, recurrent disease, and/or microscopically involved margins). Recently, we have been offering elective radiation therapy, after definitive surgery, to selected patients who have high-risk malignant melanomas. We herein report our initial results.

From 1993 to 1999, 40 patients who underwent surgery for high-risk malignant melanomas (multiple involved lymph nodes [21 patients]; close or microscopically involved surgical margins [nine patients]; extracapsular extension [six patients]; previously resected, recurrent disease [three patients]; and/or primary tumors more than 4 mm thick [four patients]) received elective radiation therapy. Thirty-six patients received 3000 cGy in five fractions (600 cGy per fraction given twice weekly), and four patients received 3600 cGy in six fractions.

At a median follow-up of 18.4 months (range, 3.8-74.1 months), the actuarial 5-year local-regional control rate was 84%. Systemic recurrence rates in these patients were similar to those reported for this subset of patients, and the actuarial overall survival rate at 5 years was 39%. Acute toxicity was limited to erythema of the skin and, in one instance, probable cellulitis, with no late sequelae.

Elective radiation therapy (600 cGy per fraction for five or six fractions) effectively controlled residual subclinical disease after surgery; however, better adjuvant systemic therapies need to be designed to eliminate distant metastases and to alter survival rates.