Adjuvant hypofractionated intensity modulated radiation therapy after resection of regional lymph node metastases in patients with cutaneous malignant melanoma of the head and neck

Purpose: To evaluate outcomes in patients with malignant melanoma of the head and neck with resected regional lymph node (LN) metastases treated with adjuvant hypofractionated intensity modulated radiation therapy (IMRT). Methods and Materials: A retrospective review was performed of 46 patients with malignant melanoma of the head and neck with regional LN metastases treated with lymphadenectomy and adjuvant IMRT. Patients underwent neck dissection (n = 42) or local excision (n = 4) for regional metastases at initial diagnosis (n = 19) or recurrence (n = 27). Adjuvant IMRT was delivered twice per week over 2.5 weeks for a total dose of 30 Gray (Gy) in 5 fractions. Acute and late adverse events were recorded using the Common Toxicity Criteria for Adverse Events version 4. Site of first recurrence was defined as local-regional (LR, above the clavicles) or distant. Overall survival, disease-free survival, and disease recurrence risks were determined using Kaplan-Meier estimates. Results: The median follow-up in living patients was 2.8 years (range, 0.2-6.9). Most patients experienced acute grade 1-2 dermatitis (80%) and mucositis (85%). One patient (2%) experienced an acute grade 3 adverse event. Seven patients (16%) experienced late grade 2 adverse events. No patient experienced grade 3 or higher late adverse events. Site of first recurrence was LR alone (n = 5), both LR and distant (n = 1), and distant alone (n = 25). Five of the 6 LR recurrences were inside the IMRT planning target volume (PTV). In-PTV and total LR control at 3 years were 85% and 76%, respectively. Overall survival and disease-free survival at 3 years were 63% and 25%, respectively. Conclusions: Adjuvant hypofractionated IMRT (30 Gy in 5 fractions) was associated with a high rate of in-PTV control and a low risk of serious adverse events.