title: Stereotactic radiosurgery of meningiomas following resection: predictors of progression.
abstract: Residual or recurrent meningiomas after initial surgical resection are commonly treated with stereotactic radiosurgery (SRS), but progression of these tumors following radiosurgery is difficult to predict. We performed a retrospective review of 60 consecutive patients who underwent resection and subsequent Gamma Knife (Elekta AB, Stockholm, Sweden) radiosurgery for residual or recurrent meningiomas at our institution from 2001-2012. Patients were subdivided by Simpson resection grade and World Health Organization (WHO) grade. Cox multivariate regression and Kaplan-Meier analyses were performed to assess risk of tumor progression. There were 45 men (75%) and 15 women (25%) with a median age of 56.8 years (range 26.5-82 years). The median follow-up period was 34.9 months (range 6-108.4 months). Simpson grade 1-3 resection was achieved in 17 patients (28.3%) and grade 4 resection in 43 patients (71.7%). Thirty-four tumors (56.7%) were WHO grade 1, and 22 (36.7%) were WHO grade 2-3. Time from resection to SRS was significantly shorter in patients with Simpson grade 4 resection compared to grade 1-3 resection (p<0.01), but did not differ by WHO grade (p=0.17). Post-SRS complications occurred in five patients (8.3%). Overall, 19 patients (31.7%) experienced progression at a median of 15.3 months (range 1.2-61.4 months). Maximum tumor diameter >2.5 cm at the time of SRS (p=0.02) and increasing WHO grade (p<0.01) were predictive of progression in multivariate analysis. Simpson resection grade did not affect progression-free survival (p=0.90). The mortality rate over the study period was 8.3%. SRS offers effective tumor control for residual or recurrent meningiomas following resection, especially for small benign tumors.
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Przybylowski
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA.
authors.forename: Daniel M S
authors.initials: DM
authors.lastname: Raper
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22903, USA; Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA, USA. Electronic address: jsheehan@virginia.edu.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008579:Meningioma / Q000601:surgery*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery; D018365:Neoplasm, Residual / Q000601:surgery; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
keywords: Gamma Knife; Meningioma; Progression; Simpson grade; Stereotactic radiosurgery; WHO grade