Endoscopic surgery combined chemoradiotherapy and PD-1 blockade in patients with sinonasal mucosal melanoma.

person Li Yan Eye & ENT Hospital, Fudan university, Shanghai, China info_outline Li Yan, Xiaole Song, Xiaoshen Wang, Hongmeng Yu

Authors person Li Yan Eye & ENT Hospital, Fudan university, Shanghai, China info_outline Li Yan, Xiaole Song, Xiaoshen Wang, Hongmeng Yu Organizations Eye & ENT Hospital, Fudan university, Shanghai, China, Eye & ENT Hospital, Fudan University, Shanghai, China; EENT Hospital, Fudan University, Shanghai, China, Eye & ENT Hospital, Fudan University, Shanghai, China Abstract Disclosures Research Funding No funding sources reported Background: Primary sinonasal mucosal melanoma (SNMM) is a rare and aggressive disease different from cutaneous melanoma. The best treatment modality including the role of immune checkpoint blockade in SNMM has not been defined. Methods: Between 2021 and 2023, patients with previously untreated sinonasal melanoma were enrolled by three single-center investigator-initiated phase II clinical trials (ChiCTR2100046498 / ChiCTR2100045797/ ChiCTR2100049031). Eligible patients in ChiCTR2100045797 trial received postoperative radical chemoradiotherapy combined with toripalimab (a PD-1 inhibitor) for a year or until the disease progressed. Eligible participants in ChiCTR2100046498 study received surgery combined with radiation without immunotherapy. And for patients in ChiCTR2100049031 study, preoperative radiation was carried out firstly. The locoregional control, distant metastasis-free survival (DMFS), and overall survival (OS) were the main efficacy goals. Results: Fifty-four patients were enrolled (mean age 62 years, 33 males [61.1%] and 21 women [38.9%]) with 2y-OS rate 62.3±7.9%, 2y-RFS rate 67.1±8.2%, and 2y-DMFS rate 63.9±8.1%. Patients with T3 (n = 23), T4a (n = 14), and T4b (n = 17) stages, including12 patients with node-positive disease, were included at baseline. During a median follow-up of 11 months, 19 patients ultimately died, 10 experienced relapses, and 17 developed metastases. Tumor T staging was demonstrated to be an independent prognostic predictor according to the Cox univariate analysis. The primary factor contributing to a poor prognosis and the primary cause of death for 73.7% of patients was distant metastases. Preoperative radiation had an improved long-term survival with 2y-OS rate of 85.7±13.2%, and it can considerably lower the risk of distant metastases (p≤0.05). The overall survival rate for patients receiving postoperative chemoradiotherapy combined with immunotherapy was higher than that for patients not receiving immunotherapy (2y-OS rate 74.1±11.4% vs. 39.3±15.8%), although the difference was not statistically significant due to a small number of patients (p = 0.16). No immune-related adverse effects grade≥3 was recorded. Conclusions: The primary cause of the poor prognostic performance of SNMM is distant metastasis. The risk of distant metastases might be considerably decreased by preoperative radiation treatment. Surgery combined with radiation and immunotherapy could bring promising survival benefit. The way forward may involve investigating the combination of immunotherapy and preoperative radiotherapy. Clinical trial information: NCT04879654; NCT05009446.

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