POSTOPERATIVE RADIOTHERAPY FOR CUTANEOUS MELANOMA OF THE HEAD AND NECK REGION

Purpose: To assess the efficacy and toxicity of elective-adjunctive ra diotherapy given in five 6-Gy fractions to patients with cutaneous mel anoma of the head and neck at high risk for local-regional relapse. Me thods and Materials: From 1983 to August 1992, 174 patients (132 men a nd 42 women) were enrolled. The ages ranged from 16 to 89 years (media n: 54 years). One group (n = 79) received elective irradiation after w ide local excision of lesions greater than or equal to 1.5 mm thick, o r Clark's level IV-V, a second group (n = 32) received adjunctive irra diation after excision of primary lesions plus limited neck dissection , and a third group (n = 63) received irradiation after neck dissectio n for nodal relapse. Each group had a projected local-regional recurre nce rate of approximately 50%. The radiotherapy consisted of five frac tions of 6 Gy each, specified at D-max, delivered twice a week, to a t otal dose of 30 Gy in 2.5 weeks. Electron beams of appropriate energie s were used whenever possible. Junction lines between adjoining fields were moved twice to minimize dose heterogeneity. Patients were seen a t regular intervals to assess disease status and therapy-related compl ications. Patients who relapsed were treated as indicated by the clini cal status. Results: With a median follow-up of 35 months, 111 of 174 patients were alive. The disease recurred above the clavicles only in six patients, at distant sites in 58 patients, and both local-regional ly and at distant sites in nine patients. The actuarial 5-year local-r egional control (LRC) and survival rates for the whole group were 88% and 47%, respectively. The thickness of the primary lesion, presence o f more than three positive nodes, and extracapsular extension did not influence the LRC rate after radiotherapy (range: 85-92%). However, le sion thickness strongly affected the 5-year survival rate of group 1 p atients (i.e., 100% for less than or equal to 1.5 mm thick, but Clark' s level IV, 72% for > 1.5-4 mm, and 30% for > 4 mm). In groups 2 and 3 , the 5-year survival rate of patients with > three involved nodes was lower than that of patients with one to three positive nodes (23% vs. 39%). The acute tolerance to adjunctive radiotherapy was excellent. L ate radiation complications were observed in only three patients. Thes e were moderate neck fibrosis, mild ipsilateral hearing impairment, an d transient exposure of external auditory canal cartilage. Conclusion: The safety of this hypofractionated radiotherapy regimen in the manag ement of cutaneous melanoma was established in this study. The overall 5-year actuarial LRC rate of 88% was much higher than that of our his torical group and that reported in the literature (50%). The survival rate of patients with lesion of 1.5-4 mm thickness was also higher tha n that observed in other series. Based on these results a prospective randomized study to further define the role of adjunctive postoperativ e radiotherapy is planned.