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.
METHOD: 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.