Postoperative radiotherapy for primary mucosal melanoma of the head and neck.

BACKGROUND: Primary head and neck mucosal melanoma (HNMM) has a poor prognosis with a low local control rate and frequent distant metastases. The objective of the current study was to determine the impact of postoperative radiotherapy on local control and survival.

METHODS: One hundred forty-two patients with primary HNMM treated between 1979 and 1997 were reviewed. Of these, 69 patients with confirmed primary mucosal melanoma, absence of metastatic disease, and definitive management by surgery with or without postoperative radiotherapy and follow-up at the Institut Gustave-Roussy (Villejuif) were selected. The site of primary HNMM was sinonasal in 46 patients, oral in 19 patients, and pharyngolaryngeal in 4 patients. Twenty-two patients (32%) had a locally advanced tumor (T3-T4) and 17 patients had regional lymph node metastases after pathologic examination (pN > 0). Thirty patients underwent surgery alone and 39 received postoperative radiotherapy. Patients with locally advanced tumors had received postoperative radiotherapy more frequently than those with small tumors (P = 0.02).

RESULTS: Thirty-seven patients (54%) experienced local disease recurrence and 47 patients (68%) developed distant metastasis. The overall survival rates were 47% at 2 years and 20% at 5 years. In the Cox multivariate analysis, patients with early T-classification tumors who received postoperative radiotherapy had a better local disease-free survival (P = 0.004 and P = 0.05, respectively) compared with patients with late T-classification tumors who did not receive postoperative radiotherapy. Patients with advanced T-classification and pN > 0 stage had a shorter distant metastasis disease-free survival compared with patients with early T-classification and pN < 0 stage. Patients with advanced T-classification tumors had a shorter overall survival compared with patients with early T-classification tumors (P = 0.003).

CONCLUSIONS: The prognosis of patients with HNMM was poor. Patients had a high rate of distant metastasis and a low rate of local control. The current study suggested that postoperative radiotherapy increased local control even for patients with small tumors.