Age-Stratified Survival Patterns in Adults with Nonmalignant Intracranial Meningioma: A Population-Based SEER Cohort Study.

BACKGROUND: Nonmalignant intracranial meningiomas are common primary CNS tumors with favorable prognosis, yet survival patterns across adulthood remain incompletely characterized. This study aims to evaluate age-stratified overall survival according to sex, race, ethnicity, tumor size, and surgical history. METHODS: This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) database to identify adults (≥18 years) diagnosed with nonmalignant intracranial meningioma from 2004 to 2022. The primary outcome was overall survival. Age-stratified Kaplan-Meier analyses and multivariable Cox proportional hazards models were constructed across five age groups (<50, 50-59, 60-69, 70-79, ≥80). RESULTS: Among 48,964 patients (75% female), mortality increased progressively with age, while surgical resection rates declined from 39% (<50 years) to 5.8% (≥80 years). Female sex was independently associated with improved survival across all age strata (HR:0.50-0.75; all p<0.001), though the magnitude attenuated with advancing age. Black patients demonstrated higher mortality than White patients in age groups under 80 years (HR:1.28-1.48; p<0.001). Surgical management was associated with improved survival across all age groups, with the largest absolute 10-year survival differences observed in patients with tumors ≥40 mm (range: 9.8%-20%) and the smallest in patients aged 70-79 years with tumors <20 mm (1.6%, p = 0.286). Tumor size ≥40 mm was the strongest independent mortality predictor (HR:1.47-1.93). CONCLUSIONS: Survival in nonmalignant intracranial meningioma varies across adulthood. Age-stratified analysis reveals heterogeneity in sex, racial, tumor-size, and treatment-related survival. These findings support individualized prognostic assessment incorporating age, tumor burden, and clinical context.