Recently the relevance of Simpsons resection grade as a prognostic factor for recurrence of WHO grade I meningiomas was challenged, contradicting many previous scientific reports and traditional neurosurgical teaching.
To study whether the predictive value of Simpson resection grade with respect to meningioma recurrence and overall survival is outdated or still valid.
Material & Methods:
All patients ≥16 years who underwent primary craniotomies for convexity meningiomas at the Oslo University affiliated hospitals (Rikshospitalet and Ullevål University Hospital) in the period 01.01.1990 – 27.01.2011 were included. Overall survival (OS) and retreatment-free survival (RFS) rates were related to patient- and surgery-specific factors.
Included in the study were 391 consecutive patients. Median age was 60.1 years (range 19 - 92). Female-to-male ratio was 2.1:1. WHO grade was grade I in 352 (90.3%), grade II in 22 (5.6%) and grade III in 16 (4.1%). Follow-up was 100%. Median follow-up time was 7.1 years (range 0.0 – 20.9 years) and total observation time was 3147 patient-years. The 1-, 5- and 10-year OS were 96%, 89% and 78%, respectively. Age, gender, WHO-grade and Simpson grade were significantly associated with OS. The 1-, 5- and 10-year RFS were 99%%, 94% and 90%, respectively. Simpson resection grade and WHO grade were significantly associated with RFS. Odds ratio for recurrence after Simpson resection grade 2/3 and 4/5 were 5.2 and 26.1 times higher than after Simpson grade 1 resection, respectively.
Simpson grade 1 resection should still be the goal for convexity meningiomas.