Patterns of recurrences in sinonasal cancers undergoing an endoscopic surgery-based treatment: Results of the MUSES* on 940 patients: *MUlti-institutional collaborative Study on Endoscopically treated Sinonasal cancers

Objectives: The improvements in survival with expansion of the survivors' population, along with evolution of endoscopically-based treatment modalities, have contributed to emphasize the clinical relevance of recurrences in sinonasal cancers. However, at present, literature is scant regarding the pattern of recurrences and the ther-apeutic strategies available to manage long survivors who experienced single or multiple failures. The aim of the present study was to analyze sinonasal cancers recurrences to provide data regarding rates and patterns of relapse, predictors of failure and prognostic impact of the recurrence.Materials and Methods: All patients receiving multimodal treatments including endoscopic surgery between 1995 and 2021 in three European referral centers were included. Statistical analysis of survival was performed through univariable, multivariable and unidirectional multistate models. Survival after recurrence analysis was imple-mented for patients experiencing at least one recurrence.Results: The 5-and 10-year recurrence free survival rates were 34.1% and 38.4% for the whole population. With a mean follow-up time of 60 months, a global recurrence rate of 32.9% was observed. The 5-and 10-year survival after recurrence rates were 27.2% and 21.7%, respectively. Incidence and rates of recurrences were significantly associated with histology subtypes.Conclusion: This study provides valuable oncologic outcomes regarding a large homogenous cohort of patients affected by sinonasal malignances treated within a multimodal framework, emphasizing the strong correlation of histologic type with prognosis, as well as with pattern of recurrences.