International Tuberculum Sellae Meningioma Study: Preoperative Grading Scale to Predict Outcomes and Inform Approach Selection

Introduction: Tuberculum sellae meningiomas (TSM) are challenging tumors that can be resected via a transcranial (TCA) or expanded endonasal approach (EEA). There is controversy about which approach is best and when to use one approach or the other. We previously published a grading scale for TSM to inform approach selection and predict post-operative outcomes using size, canal, and artery involvement. The objective of this study was to externally validate the published grading scale, refine the grading scale, validate the refined grading scale, and evaluate matched outcomes by surgical approach.

Methods: A 40-site retrospective study of TSM resected via an EEA or TCA approach was conducted (n = 947). Tumors centered on the tuberculum sellae were included. Sites were divided into an external validation and refinement cohort (27 sites, n = 626 [66%]: n = 412 TCA [66%], n = 214 EEA [34%]) and a validation cohort (13 sites, n = 321 [34%]: n = 217 TCA [68%], n = 104 EEA [32%]). Uni- and multivariate (MVA) logistic models were evaluated by area under the curve (AUC) of receiver operator curve analysis and compared using a bootstrap method. Propensity matching was used to compare EEA/TCA outcomes.

Results: The previously published grading scale was significantly prognostic for visual outcome and EOR in the validation and refinement cohort (p < 0.001). Data in the refinement cohort supported a simplified grading scale defined by: tumor-score 1 (<17 mm diameter) or 2 (≥17 mm diameter), canal-score 1 (no optic canal invasion) or 2 (any optic canal invasion), and artery-score 1 (abutting < 180 degrees) or 2 (encasing arteries > 180 degrees), which resulted in equivalent prognostic performance for vision (delta-AUC 0.02, p = 0.08) and EOR (delta-AUC 0.005, p = 0.55) compared to the published scale. The validation cohort validated the simplified grading scale for visual worsening (OR: 1.69 per point increase, 95% CI: 1.31–2.18, p < 0.001) and EOR (OR: 1.61 for STR per point, 95% CI: 1.38–1.88, p < 0.001). The simplified grading scale remained independently prognostic after adjusting for clinical covariates including age, size, WHO grade, and approach. After matching for simplified grading scale score, age, and size among the whole cohort (n =947), rates of visual worsening were similar between EEA and TCA (7.1 vs. 9.0%, EEA vs. TCA, OR: 0.78 95% CI: 0.44–1.38, p = 0.39), as was recurrence (HR: 1.01, 95% CI: 0.61–1.65, p = 0.98). Median follow-up was 26 months (range: 0–265 months). Among unfavorable tumors (simplified grading scale score: 5–6), EEA trended toward less visual worsening on MVA (OR: 0.55, 95% CI: 0.28–1.05, p = 0.07), but more STR/NTR (OR: 1.6, 95% CI: 1.1–2.33, p = 0.014), and had similar local control (HR: 1.16, 95% CI: 0.67–2.00, p = 0.59) compared to TCA.

Conclusions: We refined and validated a simplified grading scale for predicting visual outcome and EOR based on TSM preoperative tumor characteristics. EEA and TCA provide similar outcomes, but EEA trends toward better visual outcomes with higher scoring tumors, although with more STR/NTR, higher CSF leak rates and similar local control in the follow-up period studied.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
12 February 2021