Abstract 808P
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 database was prospectively designed for NPMM from Peking University Cancer Hospital. 300 patients between March 2009 and January 2020 were included and divided into SA (surgery alone, 158 patients) and SR group (surgery plus radiotherapy, 142 patients). Similarly and balanced system therapies were added into two groups. Postoperative radiotherapy was recommended, with a total dose of 65-70 Gy/30-35 fx to GTV and 60 Gy/30 Fx to CTV. The primary endpoint was relapse-free survival (RFS). The secondary endpoints included recurrence-free survival, distant metastasis-free survival (DMFS), and overall survival (OS).
Results
At a median follow-up of 50.0 months, The RFS in SA and SR groups were 9.8 and 15.2 months (HR: 0.714, 95% CI: 0.546-0.933, P = 0.014). The DMFS in SA and SR groups were 23.8 and 21.3 months (HR: 0.896, 95% CI: 15.7-31.9 vs. 13.3-29.3, P = 0.457). The 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 stage IVA patients, radiotherapy reduced the incidence of relapse by 0.43-fold with NPMM. For patients without adjuvant system therapy, radiotherapy reduced the incidence of recurrence by 0.85 times. Most adverse events were grade 1-2 and manageable.
Conclusions
Postoperative radiotherapy played a crucial role in the local control of NPMM, especially for patients with a local excision, observation only, T4a or IVA stages.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Peking University Cancer Hospital and Institute.
Funding
National Natural Science Foundation of China, Beijing Municipal Administration of Hospitals Incubating Program, Beijing Municipal Administration of Hospitals’ Youth Programme.
Disclosure
All authors have declared no conflicts of interest.