Efficacy and safety of postoperative adjuvant radiotherapy in resected nasal cavity and paranasal sinus mucosal melanoma: A Combined Analysis

Background Mucosal melanoma of the nasal cavity and paranasal sinuses (NPMM) is a highly aggressive disease. The role of postoperative adjuvant radiotherapy is controversial. Methods A total of 300 patients with NPMM treated between March 2009 and January 2020 were divided into SA (surgery alone, 158 patients) and SR (surgery plus radiotherapy, 142 patients) groups. Postoperative radiotherapy was recommended, with a total dose of 65–70 Gy/30–35 fx to the GTV (gross tumor volume) and 60 Gy/30 fractions to the CTV (clinical target volume). The primary endpoint was relapse-free survival (RFS). Secondary endpoints included local-recurrence-free survival, distant metastasis-free survival (DMFS), and overall survival (OS). Results At a median follow-up of 50.0 months, RFS in the SA and SR groups was 9.8 and 15.2 months (HR: 0.714, 95% CI: 0.546–0.933, P = 0.014). DMFS in SA and SR groups was 23.8 and 21.3 months (HR: 0.896, 95% CI: 15.7–31.9 vs. 13.3–29.3, P = 0.457). OS in SA and SR groups was 31.0 and 35.1 months (HR: 0.816, 95% CI: 25.7–36.3 vs. 27.1–43.2, P = 0.178). For patients with stage IVA NPMM, radiotherapy reduced the incidence of relapse by 0.43-fold. Conclusions Postoperative radiotherapy played a crucial role in the local control of resected NPMM, especially in patients with stage T4a or IVA disease.