Adjuvant radiotherapy plus systemic chemotherapy in resected head and neck mucosal melanoma.

Abstract

e18042 Background: The median over survival (OS) of resected head and neck mucosal melanoma (HNMM) is 49.0 months. About 65% of patients experience local recurrence or distant metastasis after surgery. Therefore, adjuvant therapy is critical to improve the poor prognosis. Methods: Data regarding HNMMs with radical surgery (stage III-IVa, AJCC HNMM 8th version) between September 1, 2006 and February 28, 2020 at Peking University Cancer Hospital was collected retrospectively. Postoperative radiotherapy was usually prescribed as GTV 60-70Gy/CTV 60Gy/30f. Patients were divided into four groups by the adjuvant regimens: radiotherapy+chemotherapy (RC), chemotherapy (C), radiotherapy (R) and observation (O). Results: In total, 368 patients were enrolled, including 104 RC,114 C, 53 R, 97 O, respectively. After median follow-up of 63.9 mo (range: 0.9-146.7), the median local relapse-free survival (LRFS) was 10.1 mo (95%CI: 6.7-13.6) in the O group, as compared with 65.9 mo (95%CI: 31.7-100.1, P＜0.001) in the R group, 75.6 mo (95%CI: 50.1-101.0, P＜0.001) in the C group, and 84.6 mo (95%CI: 48.5-120.8, P＜0.001) in the RC group. The median distant metastasis-free survival (DMFS) was 13.7 mo (95%CI: 8.0-19.5) in the O group, 15.3 mo (95%CI: 8.7-21.9, P = 0.898) in the R group, as compared with 25.7 mo (95%CI: 14.6-36.8, P = 0.001) in the C group, 49.3 mo (95%CI: 32.6-66.0, P＜0.001) in the RC group. Estimated OS was 36.4 mo (95%CI: 24.0-48.8) in the O group, as compared with 30.8 mo (95%CI: 23.0-38.6, P = 0.733) in the R group, 40.8 mo (95%CI: 34.8-46.8, P = 0.289) in the C group, 58.2 mp (95%CI: 36.4-79.9, P = 0.002) in the RC group. Primary location, age, gender, UICC staging and adjuvant regimens were included for multivariate Cox analysis. With regard to OS, UICC stage and RC were the prognostic factors. With regard to DMFS, UICC stage, RC and C were the prognostic factors. With regard to LRFS, UICC stage, RC, R, C were the prognostic factors. Conclusions: It is the largest study on the role of adjuvant radiotherapy and chemotherapy on HNMM till now. The results demonstrate that postoperative radiotherapy improves LRFS but has no impact on DMFS, while adjuvant radiotherapy plus chemotherapy prolongs OS. It further validates the clinical practice of UICC stage of HNMM, which might shed lights on the study of the whole mucosal melanoma.