Mucosal Melanoma of Head and Neck in Intensity-modulated Radiotherapy Era

Overview

In China, mucosal melanoma of head and neck (MMHN) account for 30-40% of all melanoma and the incidence is on the rise. The prognosis of MMHN is poor with the 5-year survival in a range between 20-30%. The evidence for the treatment of MMHN was weak since large-sample clinical researches are rare and no prospective clinical trial is reported. Surgery is the primary treatment modality for MMHN. However, it is difficult to extend the necessary surgery range for MMHN due to its limitation of being adjacent to the important anatomical structure in head and neck or by the considerations of the protection for organ function. As a result, the recurrence rate for surgery along was over 50%. Radiotherapy(RT) is the main approach for the multidisciplinary treatment for MMHN. Benlyazid et al. conclude the data from 13 centers and find that compared to surgery alone, the addition of post-surgery RT improve the survival; The 5-year locoregional failure rate for the surgery alone group and the RT+surgery group were 55.6% and 29.9%, respectively. Currently, the research into the prognosis factors is spare for the non-metastatic MMMHN received extended resection to primary tumor. It is necessary to undertake a prospective clinical research for MMHN in the endemic area to estimate efficacy and safety of primary surgery plus postoperative radiotherapy with or without adjuvant chemotherapy, as well as to recognize the risk distribution in this cohort of patients, provide the evidence to improve the stratification treatment strategies in the clinic.

All the patients enrolled are confirmed without any evidence of distant metastasis. All the patients receive extended resection to primary tumor and post-surgery RT. The patients are prescribed a EQD2 of 65-70Gy to CTV1 (high-risk regions including tumor bed), 50-55Gy to CTV2(low-risk regions) using Intensity-modulated radiotherapy (IMRT). The Prophylactic irradiation to upper neck is is decided by radiation physicians and given a EQD2 of 70-77Gy to CTVnd (clinically negative lymph nodes), 50-55Gy to CTVn2（neck nodal regions). If there is residual tumor, a EQD2 of 70-77Gy is prescribed to GTV. Adjuvant chemotherapy (for example, Temozolomide) is prescribed or not according the consideration of radiation physicians during RT or after RT. The clinical characteristics, radiation dose, chemotherapy regimen and the toxicities of are documented by the radiation physicians.