Multiple meningiomas: does quantity matter? a population-based survival analysis with underlined age and sex differences

Introduction: Intracranial meningiomas rarely present with multiple lesions. To the best of our knowledge, current literature regarding meningiomatosis (MM) is mostly comprised of small case series and individual reports. Hence, survival outcome data are limited. The Objective of this study is to explore the influence of sex, age, and number of lesions on overall survival (OS) in patients with MM. Methods: We obtained demographic and clinical data from the surveillance, epidemiology, and end results program (SEER) on adult patients diagnosed with meningiomas from 1975 to 2017. Univariable and multivariable analyses were conducted to assess whether number of lesions, age, and sex had a significant influence on OS. Results: 99,918 cases were included. Results showed that MM patients had a significantly decreased OS when compared to patients with a single lesion (median OS of 94 and 180 months, respectively; p < 0.001). Further analysis showed a progressive decrease on OS for every additional lesion; 2 (HR 1.659 [CI 95% 1.612–1.708], p < 0.001), 3 (HR 1.877 [CI 95% 1.773–1.988], p < 0.001), and ≥ 4 (HR 2.116 [CI 95% 1.886–2.373], p < 0.001). When assessing for sex differences, female patients had increased OS (HR 0.778 [CI 95% 0.743–0.815], p < 0.001) and decreased risk of developing MM (HR 0.809 [CI 95% 0.784–0.835], p < 0.001). Conclusion: Increasing number of meningiomas has a significant negative impact on OS, with a progressive decrease on survival for every additional lesion. Furthermore, female patients had increased OS and decreased risk to develop MM.