Efficacy and safety of primary surgery with postoperative radiotherapy in head and neck mucosal melanoma: a single-arm Phase II study

There still remains no well-established treatment strategy for head and neck mucosal melanoma (HNMM). We aim to evaluate the effectiveness and safety of primary surgery with postoperative radiotherapy for this disease. A single-arm, Phase II clinical trial was conducted at Sun Yat-Sen University Cancer Center. Patients with nonmetastatic, histologically proven HNMM were prospectively enrolled. Patients received primary surgery followed by intensity-modulated radiotherapy with an equivalent dose at 2 Gy per fraction of 65-70 Gy to CTV1 (high-risk regions including tumor bed) and 50-55 Gy to CTV2 (low-risk regions). Additional use of adjuvant chemotherapy (AC) depended on consultation from a multidisciplinary team. This trial is registered with ClinicalTrials.gov, number NCT03138642. A total of 33 patients were enrolled and analyzed between July 2010 and November 2016. There were 18 (54.5%) patients with T3 disease and 15 (45.5%) patients with T4a disease. The median age at diagnosis was 58 years (range 27-83 years), and 61% of the cohort were males. The overall median follow-up duration was 25.3 months (range 5.3-67.1 months). The 3-year overall survival (OS), local relapse-free survival (LRFS), regional relapse-free survival (RRFS), and distant metastasis-free survival (DMFS) rates were 44.4, 91.7, 78.1, and 41.7%, respectively. Patients with T4a disease showed significantly inferior OS ( =0.049) and DMFS ( =0.040) than those with T3 disease. Prophylactic neck radiation (PNR) was nearly associated with superior RRFS ( =0.078). However, there was no significant difference in OS, LRFS, RRFS, and DMFS for patients treated with or without AC ( >0.05 for all). Toxicities were generally mild to moderate. Primary surgery with postoperative radiotherapy yielded excellent local control and acceptable toxicity profile for HNMM. Nevertheless, high rates of distant metastases resulted in limited survival.