Clinical outcome of 1,968 cases of meningiomas from Kaiser Permanente Northern California.

2062 Background: Meningioma is the most common primary brain tumor in the United States, but there is limited data on clinical outcomes. Methods: We performed descriptive and survival analysis of meningioma cases diagnosed 2001-2010 from the Kaiser Permanente Northern California Cancer Registry, which began inclusion of benign brain tumors in 2001. Datasets provided variables on gender, age at diagnosis, race, and vital status. Chart review extracted additional information on mortality, histology, imaging, tumor size, tumor site, and treatment. We used Kaplan Meier method to calculate overall survival (OS) and disease-free survival (DFS) and log-rank test to compare survival rates by variables. Cox proportional hazard models were used to analyze variables relative to endpoints. Results: 1968 cases in 1792 patients with meningioma were analyzed. 55% of cases had histological confirmation. 5- and 10-year OS and DFS for all groups were 76% & 61% and 89% & 82%. Disease progression and recurrence presented in 10% of cases at 10 years, resulting in 4% disease-specific mortality (DSM). Statistically significant prognostic factors of worse DFS were age >= 80, WHO grade 2-3, tumor size >= 18 mm, peritumoral edema on imaging, Simpson grades (SG) 4 or 5, and no surgery. Factors associated with significantly worse OS included age >= 60, male gender, tumor size >= 42 mm, peritumoral edema, SG 4 or 5, no histology and no treatment (NT). SG 1-3 groups provided statistically the highest OS and DFS. There was no significant difference in DFS or OS for definitive RT versus surgery and adjuvant RT groups. Definitive RT showed significantly better OS than NT (HR=0.46, 95% CI: 0.21-0.98). Cases with progression or recurrence had 51% DSM with 65% of deaths associated with lack of salvage therapy. Salvage RT provided better OS benefit compared to other salvage groups (HR=0.35, 95% CI: 0.14-0.91). Conclusions: We demonstrated favorable long-term outcome for meningiomas and confirmed the prognostic benefit of Simpson grading. We have identified additional adverse factors affecting outcome. While surgery remains standard, definitive RT demonstrates comparable outcome to cases not amenable to gross total resection. Salvage RT is effective, providing a survival benefit.