Purpose: To evaluate the efficacy of carbon ion radiotherapy for mucosal malignant melanoma of the head and neck.
Methods and materials: Between 1994 and 2004, 72 patients with mucosal malignant melanoma of the head and neck were treated with carbon ion beams in three prospective studies. Total dose ranged from 52.8 GyE to 64 GyE given in 16 fixed fractions over 4 weeks. Clinical parameters including gender, age, Karnofsky index, tumor site, tumor volume, tumor status, total dose, fraction size, and treatment time were evaluated in relation to local control and overall survival.
Results: The median follow-up period was 49.2 months (range, 16.8-108.5 months). Treatment toxicity was within acceptable limits, and no patients showed Grade 3 or higher toxicity in the late phase. The 5-year local control rate was 84.1%. In relation to local control, there were no significant differences in any parameters evaluated. The 5-year overall and cause-specific survival rates were 27.0% and 39.6%, respectively. For overall survival, however, tumor volume (>/=100 mL) was found to be the most significant prognostic parameter. Of the patients who developed distant metastasis, 85% were free from local recurrence.
Conclusion: Carbon ion radiotherapy is a safe and effective treatment for mucosal malignant melanoma of the head and neck in terms of high local control and acceptable toxicities. Overall survival rate was better than in those treated with conventional radiotherapy and was comparable to that with surgery.