title: Surgically resected skull base meningiomas demonstrate a divergent postoperative recurrence pattern compared with non-skull base meningiomas.
abstract: OBJECTIVE The objective of this study was to identify the natural history and clinical predictors of postoperative recurrence of skull base and non-skull base meningiomas. METHODS The authors performed a retrospective hospital-based study of all patients with meningioma referred to their institution from September 1993 to January 2014. The cohort constituted both patients with a first-time presentation and those with evidence of recurrence. Kaplan-Meier curves were constructed for analysis of recurrence and differences were assessed using the log-rank test. Cox proportional hazard regression was used to identify potential predictors of recurrence. RESULTS Overall, 398 intracranial meningiomas were reviewed, including 269 (68%) non-skull base and 129 (32%) skull base meningiomas (median follow-up 30.2 months, interquartile range [IQR] 8.5-76 months). The 10-year recurrence-free survival rates for patients with gross-total resection (GTR) and subtotal resection (STR) were 90% and 43%, respectively. Skull base tumors were associated with a lower proliferation index (0.041 vs 0.062, p = 0.001), higher likelihood of WHO Grade I (85.3% vs 69.1%, p = 0.003), and younger patient age (55.2 vs 58.3 years, p = 0.01). Meningiomas in all locations demonstrated an average recurrence rate of 30% at 100 months of follow-up. Subsequently, the recurrence of skull base meningiomas plateaued whereas non-skull base lesions had an 80% recurrence rate at 230 months follow-up (p = 0.02). On univariate analysis, a prior history of recurrence (p < 0.001), initial WHO grade following resection (p < 0.001), and the inability to obtain GTR (p < 0.001) were predictors of future recurrence. On multivariate analysis a prior history of recurrence (p = 0.02) and an STR (p < 0.01) were independent predictors of a recurrence. Assessing only patients with primary presentations, STR and WHO Grades II and III were independent predictors of recurrence (p < 0.001 for both). CONCLUSIONS Patients with skull base meningiomas present at a younger age and have less aggressive lesions overall. Extent of resection is a key predictor of recurrence and long-term follow-up of meningiomas is necessary, especially for non-skull base tumors. In skull base meningiomas, recurrence risk plateaus approximately 100 months after surgery, suggesting that for this specific cohort, follow-up after 100 months can be less frequent.
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;|Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton; and.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mansouri
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: George
authors.initials: G
authors.lastname: Klironomos
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: Shervin
authors.initials: S
authors.lastname: Taslimi
authors.affiliation: Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: Alex
authors.initials: A
authors.lastname: Kilian
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: Fred
authors.initials: F
authors.lastname: Gentili
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: Osaama H
authors.initials: OH
authors.lastname: Khan
authors.affiliation: Department of Pathology, University of Toronto, Ontario, Canada.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Aldape
authors.affiliation: Division of Neurosurgery, University of Toronto;|Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto;
authors.forename: Gelareh
authors.initials: G
authors.lastname: Zadeh
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000453:epidemiology* / Q000601:surgery*; D008579:Meningioma / Q000453:epidemiology* / Q000601:surgery*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D012189:Retrospective Studies; D019291:Skull Base
keywords: CI = confidence interval; EOR = extent of resection; GTR = gross-total resection; IQR = interquartile range; NF2 = neurofibromatosis Type 2; OR = odds ratio; PR = progesterone receptor; STR = subtotal resection; meningioma; postoperative period; recurrence; skull base