Article
The prognostic role of Simpson grading in meningioma –still relevant after 62 years?
Die prognostische Rolle des Simpson Grads in Meningeomen – nach 62 Jahren noch relevant?
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Published: | June 26, 2020 |
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Objective: Since the proclamation of the Simpson grading for the extent of resection in meningiomas in 1957, many more insights have been gained regarding the biology, histopathological classification and treatment of meningiomas. Until today the Simpson grading determines the intraoperative course during meningioma resection, believing that a Simpson grade II resection is better for the patient than grade III for example. In the light of the established prognostic factors in meningiomas, this retrospective analysis aims to clarify to what extent the Simpson grading in its single cutoffs is still of prognostic significance for our patients.
Methods: We analyzed the clinical and histopathological data of 429 meningiomas that were surgically resected in the authors' institution between 04/2011 bis 12/2015. Operative reports were reviewed regarding the extent of resection according to the Simpson grading system. Meningioma subtype according to the WHO classification of 2016 as well as histopathological brain invasion and time of progression were retrieved from clinical records. Univariate and multivariate analyses were applied.
Results: Altogether 49 meningiomas showed tumor recurrence (49/429, 11.4%) after a mean follow-up of 31 months (1.7-95.7 months). The rate of recurrence increased with each Simpson grading step. Meningiomas operated according to Simpson grade I showed only 4.4% recurrences (4/90) while grade II and III had highe rates of 5.5% (7/126) and 12.6% (12/95). Tumors resected according to Simpson grade IV, meaning a subtotal resection, had the highest rate of recurrence with 23.3 % (24/103) (Pearson's chi-squared test, p<.0001). Multivariate analysis including WHO grade and Simpson grade at all different cutoffs revealed that next to the WHO grading (p=0.0443) only the cut off at Simpson grade 3 and 4 has independent prognostic value (p=0.0423). Cut offs between Simpson grade 1 and 2 as well as 2 and 3 have no independent prognostic significance.
Conclusion: Incomplete tumor resection after microsurgical meningioma resection remains an independent prognostic factor with a higher rate of tumor recurrence. The multivariate analysis of this cohort does not show a prognostic benefit between Simpson grades 1/2 and 2/3, suggesting that the efforts we make and the risks we take when encountering the dural attachment of meningiomas have a questionable prognostic impact.