title: Simpson grade: an opportunity to reassess the need for complete resection of meningiomas.
abstract: BACKGROUND
  The relevance of the Simpson grading system as a predictor of meningioma progression or recurrence in modern neurosurgical practice has recently been called into question. The aim of our study was to compare the risk of progression/recurrence of tumours that had been treated with different Simpson grade resections in a contemporary population of benign (WHO grade I) meningioma patients.
  
  
  METHODS
  One hundred eighty-three patients with histologically confirmed WHO grade I meningioma were retrospectively analysed. All patients underwent first-time craniotomy as their initial therapy between 2004 and 2012. Univariate analysis was performed using log-rank testing and Kaplan-Meier analysis for progression/recurrence-free survival. Multivariate analysis was performed using Cox proportional hazards regression modelling.
  
  
  RESULTS
  The three-year progression/recurrence-free survival rates for patients receiving Simpson grade 1, 2 or 4 resections were 95 %, 87 % and 67 %, respectively. Simpson grade 4 resections progressed/recurred at a significantly greater rate than Simpson grade 1 resections (hazard ratio [HR] = 3.26, P = 0.04), whereas Simpson grade 2 resections did not progress/recur at a significantly greater rate than Simpson grade 1 resections (HR = 1.78, P = 0.29). Subtotal resections progressed/recurred at a significantly greater rate than gross-total resections (HR = 2.47, P = 0.03).
  
  
  CONCLUSIONS
  Tumours that undergo subtotal resection are at a significantly greater risk of progression/recurrence than tumours that undergo gross-total resection. Gross-total resection should therefore be the aim of surgery. However, given modern access to follow-up imaging and stereotactic radiosurgery, these results should not be used to justify overly 'heroic' tumour resection.
authors.affiliation: Department of Neurosurgery, Royal Hallamshire Hospital, Glossop Road, Sheffield, UK, S102JF.
authors.forename: James Barry
authors.initials: JB
authors.lastname: Heald
authors.forename: Thomas Anthony
authors.initials: TA
authors.lastname: Carroll
authors.forename: Richard James
authors.initials: RJ
authors.lastname: Mair
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000601:surgery*; D008579:Meningioma / Q000473:pathology* / Q000601:surgery*; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult