Postoperative Radiotherapy in Head and Neck Mucosal Melanoma

OBJECTIVE: to report patterns of failure according to treatment modality, with an emphasis on the role of postoperative radiotherapy in patients with localized head and neck mucosal melanoma (HNMM) treated during a 28-year period in a multi-institutional setting. DESIGN: retrospective review. SETTING: french medical institutions. PATIENTS: a total of 160 patients with nonmetastatic HNMM treated from 1980 through 2008. INTERVENTIONS: treatment modality consisted of surgery alone (hereinafter, S group) (n = 82 patients) or with postoperative radiotherapy (hereinafter, SRT group) (n = 78). Patients and tumor characteristics were similar in the 2 groups. There was a nonsignificant trend (P = .11) for more locally advanced tumor stage (38.9%) in the SRT group compared with the S group (24.5%). RESULTS: patients in the S group had an increased probability of locoregional recurrence as a first event (55.6%) compared with those in the SRT group (29.9%; P < .01). After adjusting for tumor stage (T1/T2 vs T3/T4), the subdistribution hazard ratio of locoregional relapse was 0.31, (95% confidence interval CI, 0.15-0.61; P < .01).The rate of distant metastasis as a first event was significantly higher in the SRT group (40.6%) compared with the S group (19.9%; P = .01). Regardless of their treatment, patients who had a locoregional relapse during follow-up had an increased risk of subsequent distant metastasis (hazard ratio, 3.07; 95% CI, 1.65-5.67) and death (hazard ratio, 3.01; 95% CI, 1.91-4.78). CONCLUSIONS: this large retrospective study suggests that postoperative radiotherapy improves the locoregional control of HNMM. The higher rate of distant metastasis was due to more advanced disease in the SRT group.