Long-Term Outcomes of Stereotactic Radiosurgery for Postoperative World Health Organization Grade I Skull Base Meningioma: Utility of Ki-67 Labeling Index as a Prognostic Indicator

Assessing the predictive value of Ki-67 and progesterone receptor algorithms for recurrence and disease-free survival in meningiomas

Sophisticated refinements in histopathology are evolving to improve meningioma outcome prediction. The aim of this study is to evaluate the stand-alone performance of Ki-67 and progesterone receptor (PR) algorithm scores in meningiomas and their power in predicting recurrence and disease-free survival of the patients. Whole slide images of Ki-67 and PR-stained slides from 404 meningioma cases were analyzed by a digital image viewer and analysis software Virapath-2.1, which analyzes the tumor cells by size, color, and shape. Ki-67 scores were calculated in the hotspot region that contains at least 1000 tumor cells, while PR was calculated on the whole slide. The results were compared with WHO grade, tumor recurrence and disease-free survival (DFS). Mean Ki-67 scores were 4.2 ± 3.5, 12.1 ± 10.6 and 22. ± 8.5 for grade 1, 2 and 3 tumors (p < 0.05), while PR scores were 49 ± 35, 43 ± 34 and 16 ± 30, respectively (p > 0.05). Median survival of patients based on Ki-67 values ≤13.2 % and > 13.2 % was 122 versus 60 months (p = 0.004). Prediction of recurrence based on Ki-67 score was found to have acceptable discrimination (AUC = 0.74). PR expression was not found to correlate with DFS, but recurrent tumors had lower PR scores than non-recurrent tumors (31.3 ± 33.8 vs. 49.0 ± 33.0; p = 0.03). Elevated Ki-67 levels identified by the algorithm may classify meningioma patients at high recurrence risk and inform clinical management. Although PR scores did not correlate with DFS, lower expression in recurrent tumors suggests a role in recurrence risk assessment. Larger prospective studies are needed for routine clinical practice.

A multi-modal deep learning model for prediction of Ki-67 for meningiomas using pretreatment MR images

This study developed and validated a deep learning network using baseline magnetic resonance imaging (MRI) to predict Ki-67 status in meningioma patients. A total of 1239 patients were retrospectively recruited from three hospitals between January 2010 and December 2023, forming training, internal validation, and two external validation cohorts. A representation learning framework was utilized for modeling, and performance was assessed against existing methods. Furthermore, Kaplan-Meier survival analysis was conducted to investigate whether the model could be used for tumor growth prediction. The model achieved superior results, with areas under the curve (AUCs) of 0.797 for internal testing and 0.808 for generalization, alongside 0.756 and 0.727 for 3- and 5-year tumor growth predictions, respectively. The prediction was significantly associated with the growth of asymptomatic small meningiomas. Overall, the model provides an effective tool for early prediction of Ki-67 and tumor volume growth, aiding in individualized patient management.

Effectiveness and safety of hypofractionated gamma knife radiosurgery for large meningiomas and those adjacent to the optic pathway and brainstem: preliminary therapeutic outcomes

Recent technologic advancements have facilitated the use of hypofractionated Gamma Knife-based radiosurgery (HF-GKRS) to treat large lesions or those in eloquent areas. This study aimed to analyze the preliminary results of HF-GKRS for these meningiomas, and to determine its effectiveness and safety. This single-center retrospective study analyzed data of patients who underwent HF-GKRS for large meningiomas or those in eloquent areas with > 6 months of follow-up. The primary outcome was progression-free survival (PFS). The secondary outcomes were neurological deterioration, post-treatment T2 signal changes following HF-GKRS, and tumor volume changes. Volumetric analysis of the tumors after treatment was also performed to assess changes in tumor size after HF-GKRS. Overall, 24 patients with a median follow-up period of 22 months (range: 6-49 months) were included. Among them, 18 (75%) patients had tumors in close proximity to the optic pathway, and 15 (63%) patients had large lesions (> 10 cm3). The cumulative 1- and 3-year PFS rates were 100% and 92%, respectively. The cumulative 3-year rate of adverse radiation effects was 9%. Overall, 12 patients (50%) showed tumor reduction, with a median tumor reduction rate of 45% (range: 25-58%). Our preliminary results revealed that HF-GKRS for large meningiomas or those in eloquent areas is safe and effective, with satisfactory short- and mid-term PFS and low adverse radiation effects. Further research with more patients and longer follow-up periods is required.

Ki-67 labeling index predicts tumor progression patterns and survival in patients with atypical meningiomas following stereotactic radiosurgery

PURPOSE

This study investigated whether Ki-67 labeling index (LI) correlated with clinical outcomes after SRS for atypical meningiomas.

METHODS

This retrospective study examined 39 patients with atypical meningiomas who underwent SRS over a 10-year study period. Ki-67 LI was categorized into 3 groups: low (< 5%), intermediate (5%-10%), and high (> 10%). Local tumor control rates (LCRs), progression-free rates (PFRs), disease-specific survival (DSS) rates, and adverse radiation-induced events (AREs) were evaluated.

RESULTS

The median follow-up periods were 26 months. SRS was performed at a median prescription dose of 18 Gy for tumors with a median Ki-67 LI of 9.6%. The 3-year LCRs were 100%, 74%, and 25% in the low, intermediate, and high LI groups, respectively (p = 0.011). The 3-year PFRs were 100%, 40%, and 0% in the low, intermediate, and high LI groups (p = 0.003). The 5-year DSS rates were 100%, 89%, and 50% in the low, intermediate, and high LI groups (p = 0.019). Multivariable Cox proportional hazard analysis showed a significant correlation of high LI with lower LCR (hazard ratio [HR], 3.92; 95% confidence interval [CI] 1.18-13.04, p = 0.026), lower PFR (HR 3.80; 95% CI 1.46-9.88, p = 0.006), and shorter DSS (HR 6.55; 95% CI 1.19-35.95, p = 0.031) compared with intermediate LI. The ARE rates were minimal (8%) in the entire group.

CONCLUSION

Patients with high Ki-67 LI showed significantly more tumor progression and tumor-related death. Ki-67 LI might offer valuable predictive insights for the post-SRS management of atypical meningiomas.