Outcomes of salvage radiation for recurrent world health organization grade II meningiomas: a retrospective cohort study

Establishment and transcriptomic characteristics of radio-resistant meningioma cell lines

PURPOSE

Radio-resistance poses a significant challenge in meningioma treatment. This study aimed to establish radio-resistant meningioma cell lines and uncover molecular mechanisms driving radio-resistance to identify potential biomarkers and therapeutic targets.

METHODS

Radio-resistant meningioma cell lines (IOMM-Lee-RR, CH157-RR) were developed using a progressive radiation dose (cumulative 90 Gy). Cell morphology, radiosensitivity, apoptosis, viability, migration, invasion, cell cycle, and DNA damage repair were analyzed via clonogenic assays, flow cytometry, and Western blotting. Transcriptome sequencing was performed to identify differentially expressed genes (DEGs), followed by KEGG and GO enrichment analyses. Protein-protein interaction (PPI) analysis was conducted to identify hub genes. TK1 expression was further validated in a cohort of 350 meningiomas and the GSE189672 dataset.

RESULTS

Radio-resistant meningioma cell lines exhibited enhanced survival, reduced apoptosis, increased cell viability, and superior migratory and invasive abilities compared to parental cells. Under radiation, these cells showed G0/G1 phase accumulation and reduced G2/M phase arrest, along with enhanced DNA repair capacity, as evidenced by lower γ-H2AX expression and fewer DNA damage foci. Transcriptome analysis revealed significant enrichment in metabolic pathways, DNA repair, and cell cycle regulation. Among 34 hub genes identified, TK1 emerged as a key gene, being highly expressed in recurrent and high-grade meningiomas and positively correlated with Ki67. Analysis of the GSE189672 dataset confirmed TK1 as a poor prognostic factor associated with tumor recurrence.

CONCLUSION

Radio-resistant meningioma cells exhibit enhanced DNA repair, migration, invasion, and altered cell cycle dynamics. TK1 was identified as a promising biomarker and therapeutic target for overcoming radio-resistance in meningiomas.

A high content clonogenic survival drug screening identifies maytansine as a potent radiosensitizer for meningiomas

Purpose

Radiation resistance significantly hinders the efficacy of radiotherapy for meningiomas, posing a primary obstacle. The clinical inadequacy of therapeutic drugs and radiosensitizers for treating meningiomas further exacerbates the challenge. Therefore, the aim of this study was to identify potential radiosensitizers for treating meningiomas.

Methods

A high content clonogenic survival drug screening was employed to evaluate 166 FDA-approved compounds across varied concentration ranges. Cell viability, apoptosis, and radiosensitization were assessed using CCK-8 assays, Annexin V-FITC/PI assays and standard colony formation assays. Transcriptome sequencing, immunofluorescence and cell cycle experiments were conducted to assess transcriptional profile, DNA double-strand break damage and cell cycle distribution. Finally, the radiosensitizing effect of Maytansine was assessed in vivo through subcutaneous tumor implantation in nude mice.

Results

The proportion of maytansine exhibiting SRF≥1.5 within the detectable concentration range was 100%. CCK-8 assay indicated the IC50 values of maytansine for IOMM-Lee and CH157 were 0.26 ± 0.06 nM and 0.31 ± 0.01 nM, respectively. Standard clonogenic survival assays and Annexin V-FITC/PI assays revealed maytansine had a notable radiosensitizing effect on meningioma cells. Transcriptome sequencing analysis demonstrated that maytansine can modulate cell cycle and DNA damage repair. Immunofluorescence analysis of γ-H2AX and cell cycle experiments demonstrated that Maytansine enhances DNA double-strand breaks and induces G2/M phase arrest. Moreover, in vivo studies had indicated that Maytansine augments the therapeutic efficacy of radiotherapy.

Conclusion

This study highlighted the potential of maytansine as a potent inhibitor and radiosensitizer for meningiomas by inducing G2/M phase cell cycle arrest and enhancing DNA double-strand break damage. These findings opened up a promising path in the development of radiosensitizers aimed at treating this condition.

Outcomes of adjuvant radiation treatment following subtotal resection of world health organization grade II meningiomas

PURPOSE

Existing literature on adjuvant radiation after subtotal resection (STR) of WHO II meningiomas is limited by heterogenous patient cohorts, combining adjuvant and salvage radiation, gross total resection (GTR) and STR, primary radiation treatment vs. re-treatment, or grade II and III meningiomas, all of which have different expected outcomes. Tumor control estimates in a large homogenous patient cohort are needed to accurately counsel patients.

METHODS

A retrospective review of patients that had immediate post-operative imaging-confirmed residual WHO grade II meningioma followed by either adjuvant intensity-modulated radiation therapy (IMRT) or stereotactic radiosurgery (SRS) between 1996 and 2020 was conducted. Kaplan-Meier survival analysis and log-rank test was used to assess progression-free survival (PFS).

RESULTS

Thirty-nine patients met inclusion criteria (IMRT = 32; SRS = 7). Overall, the 3-, 5-, and 10-year PFS was 81.1%, 61.2%, and 44.6%, respectively. Median follow-up time was 37 months. When comparing IMRT and SRS cohorts, baseline characteristics did not differ significantly between groups, but significantly larger residual tumor volumes were treated with IMRT (22.2 cm3 vs. 6.3 cm3, p = 0.004). PFS was not significantly different between IMRT and SRS at 3 years (81.1% vs. 80.0%) or 5 years (65.5% vs. 40%) (p = 0.19). There was no significant difference in radiation necrosis between groups (IMRT = 3/32 patients vs. SRS = 0/7 patients, p = 0.32).

CONCLUSION

Our homogenous patient cohort displayed acceptable control rates at 3 years using SRS or IMRT as adjuvant therapy. No significant difference in PFS or radiation necrosis was noted between patients treated with adjuvant IMRT versus SRS.

Radiosurgery for Intracranial Meningiomas: A Review of Anatomical Challenges and an Update on the Evidence

Radiation has been used to treat meningiomas since the mid-1970s. Traditionally, radiation was reserved for patients unfit for major surgery or those with surgically inaccessible tumors. With an increased quantity and quality of imaging, and an aging population, there has been a rise in incidentally diagnosed meningiomas with smaller tumors at diagnosis time. Deciding if, how, and when to intervene must be determined on a case-by-case basis. Anatomical location and adjacent vital structures are crucial for decision-making. Prior review articles have detailed outcomes of radiosurgery in broad anatomical regions such as the skull base, but a recent deluge of research on increasingly specific anatomical subregions deserves attention. This narrative review synthesizes information regarding specific anatomical subregions, including anatomical challenges, radiosurgical outcomes, and unique considerations. Via MEDLINE and ascendancy search, we utilized evidence available for each anatomical region and herein discuss details of published research and explore future directions. Meningioma management remains individualized based on patient comorbidities, tumor location/characteristics, symptomatic burden, and patient age. In addition to stereotactic radiosurgery's established role for surgically inaccessible, recurrent, and high-grade meningiomas, its use as upfront management for small asymptomatic meningiomas is increasingly investigated. For all subregions reported, radiosurgical intervention resulted in high tumor control rates and acceptably low adverse radiation events.

Salvage Stereotactic Radiosurgery for Recurrent WHO Grade 2 and 3 Meningiomas: A Multicenter Study (STORM)

PURPOSE

The role of stereotactic radiosurgery (SRS) in the management of grade 2 and 3 meningiomas is not well elucidated. Unfortunately, local recurrence rates are high, and guidelines for management of recurrent disease are lacking. To address this knowledge gap, we conducted STORM (Salvage Stereotactic Radiosurgery for Recurrent WHO Grade 2 and 3 Meningiomas), a multicenter retrospective cohort study of patients treated with primary SRS for recurrent grade 2 and 3 meningiomas.

METHODS AND MATERIALS

Data on patients with recurrent grade 2 and 3 meningioma treated with SRS at first recurrence were retrospectively collected from 8 academic centers in the United States. Patients with multiple lesions at the time of initial diagnosis or more than 2 lesions at the time of first recurrence were excluded from this analysis. Patient demographics and treatment parameters were extracted at time of diagnosis, first recurrence, and second recurrence. Oncologic outcomes, including progression-free survival (PFS) and overall survival, as well as toxicity outcomes, were reported at the patient level.

RESULTS

From 2000 to 2022, 108 patients were identified (94% grade 2, 6.0% grade 3). A total of 106 patients (98%) had upfront surgical resection (60% gross-total resection) with 18% receiving adjuvant radiation therapy (RT). Median time to first progression was 2.5 years (IQR, 1.34-4.30). At first recurrence, patients were treated with single or fractionated SRS to a median marginal dose of 16 Gy to a maximum of 2 lesions (87% received single-fraction SRS). The median follow-up time after SRS was 2.6 years. The 1-, 2-, and 3-year PFS was 90%, 75%, and 57%, respectively, after treatment with SRS. The 1-, 2-, and 3-year overall survival was 97%, 94%, and 92%, respectively. In the multivariable analysis, grade 3 disease (HR, 6.80; 95% CI, 1.61-28.6), male gender (HR, 3.48; 95% CI, 1.47-8.26), and receipt of prior RT (HR, 2.69; 95% CI, 1.23-5.86) were associated with worse PFS. SRS dose and tumor volume were not correlated with progression. Treatment was well tolerated, with a 3.0% incidence of grade 2+ radiation necrosis.

CONCLUSIONS

This is the largest multicenter study to evaluate salvage SRS in recurrent grade 2 and 3 meningiomas. In this select cohort of patients with primarily grade 2 meningioma with a potentially more favorable natural history of delayed, localized first recurrence amenable to salvage SRS, local control rates and toxicity profiles were favorable, warranting further prospective validation.

Predictors of salvage therapy for parasagittal meningiomas treated with primary surgery, radiosurgery, or surgery plus adjuvant radiotherapy

OBJECTIVE

Parasagittal meningiomas (PM) are treated with primary microsurgery, radiosurgery (SRS), or surgery with adjuvant radiation. We investigated predictors of tumor progression requiring salvage surgery or radiation treatment. We sought to determine whether primary treatment modality, or radiologic, histologic, and clinical variables were associated with tumor progression requiring salvage treatment.

METHODS

Retrospective study of 109 consecutive patients with PMs treated with primary surgery, radiation (RT), or surgery plus adjuvant RT (2000-2017) and minimum 5 years follow-up. Patient, radiologic, histologic, and treatment data were analyzed using standard statistical methods.

RESULTS

Median follow up was 8.5 years. Primary treatment for PM was surgery in 76 patients, radiation in 16 patients, and surgery plus adjuvant radiation in 17 patients. Forty percent of parasagittal meningiomas in our cohort required some form of salvage treatment. On univariate analysis, brain invasion (OR: 6.93, p < 0.01), WHO grade 2/3 (OR: 4.54, p < 0.01), peritumoral edema (OR: 2.81, p = 0.01), sagittal sinus invasion (OR: 6.36, p < 0.01), sagittal sinus occlusion (OR: 4.86, p < 0.01), and non-spherical shape (OR: 3.89, p < 0.01) were significantly associated with receiving salvage treatment. On multivariate analysis, superior sagittal sinus invasion (OR: 8.22, p = 0.01) and WHO grade 2&3 (OR: 7.58, p < 0.01) were independently associated with receiving salvage treatment. There was no difference in time to salvage therapy (p = 0.11) or time to progression (p = 0.43) between patients receiving primary surgery alone, RT alone, or surgery plus adjuvant RT. Patients who had initial surgery were more likely to have peritumoral edema on preoperative imaging (p = 0.01). Median tumor volume was 19.0 cm3 in patients receiving primary surgery, 5.3 cm3 for RT, and 24.4 cm3 for surgery plus adjuvant RT (p < 0.01).

CONCLUSION

Superior sagittal sinus invasion and WHO grade 2/3 are independently associated with PM progression requiring salvage therapy regardless of extent of resection or primary treatment modality. Parasagittal meningiomas have a high rate of recurrence with 80.0% of patients with WHO grade 2/3 tumors with sinus invasion requiring salvage treatment whereas only 13.6% of the WHO grade 1 tumors without sinus invasion required salvage treatment. This information is useful when counseling patients about disease management and setting expectations.

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.

Spheno-Orbital Meningioma - Treatment Outcomes and Factors Influencing Recurrence

PURPOSE

To determine treatment outcomes, recurrence rates, and predictors of recurrence, to inform future therapeutic approaches for spheno-orbital meningiomas (SOM).

METHODS

A retrospective single-center study of SOM treated from 1990 to 2021 was conducted with comprehensive neuro-ophthalmologic follow-up at Columbia University Medical Center (CUMC). Recurrence requiring reintervention was defined clinically as worsening of visual acuity, visual field defect, or ocular motility after an initial period of stabilization or 6 months of improvement following treatment, or radiologically as either a regrowth with an increase in tumor size by 20% at the site of previous growth or a new region of tumor growth.

RESULTS

In total 46 patients met the inclusion criteria. The mean follow-up was 106 months (range 1-303). Dictated by the phenotype of the disease, patients underwent either gross- (50%), near- (17%), or subtotal resection (26%). Removal of the anterior clinoid process (ACP) was performed in 52% of patients. Nine patients (20%) required an enucleation or exenteration. Radiotherapy was employed at some point of treatment in 50% of cases. Inherited cases (24%) were referred to CUMC for treatment following 1 or more recurrences. The total recurrence rate, including inherited cases, was 54%, occurring at a mean interval of 43 months. The recurrence rate of patients treated solely at CUMC was 40%, occurring at a mean interval of 41 months. A subset of patients (32%) had 2 or more recurrences. Histopathology at the first surgery was WHO grade I (87%) and II (13%) and at the final surgery was WHO grade I (74%), II (21%), and III (4%). A subset of grade I tumors that received radiotherapy (35%) evolved to a higher grade or developed multiple recurrences without a change in histologic grade I. Grade II tumors and treatment with radiotherapy increased the odds of recurrence. Removal of the ACP and gross total resection decreased the odds of recurrence.

CONCLUSION

Due to the routinely long interval to tumor recurrence, lifelong surveillance of patients with SOM is prudent. ACP resection and gross total resection, where possible, reduce tumor recurrence and the need for further treatment. Radiotherapy should be reserved for higher-grade meningiomas and select grade I tumors.

Meningioma transformation to glioblastoma following stereotactic radiosurgery: A case report and review of the literature

Background

Meningiomas are the most common primary intracranial tumor with increasing incidence. Stereotactic Radiosurgery Gamma Knife (SRS-GK) is a commonly used modality for neoadjuvant and adjuvant treatment of these tumors and is often necessary for long-term disease control, particularly for the World Health Organization grade II/III meningiomas. While there is strong evidence to support the use of SRS-GK for meningioma, there exists a risk of secondary malignancy that is not well understood. We report a case of glioblastoma (GBM) that arose near the bed of a meningioma previously treated with SRS-GK and discuss other cases of GBM that emerged at a site of meningioma reported in the literature.

Case Description

A 79-year-old female with a history of a blood-clotting disorder presented to the hospital with sudden facial sensory disturbances. On magnetic resonance imaging (MRI), a homogeneously enhancing lesion was observed in the right temporal lobe, consistent with a meningioma. Following 2 years of surveillance, the patient underwent SRS-GK for enlargement of the lesion. The patient later presented with headache and gait instability 12 years following SRS-GK. MRI revealed a large ring-enhancing lesion with surrounding edema histologically confirmed to be a GBM. At 9 months following initial tumor resection and a combination of radiotherapy and temozolomide, the patient was neurologically intact.

Conclusion

There is a very small risk of meningioma to GBM conversion following SRS. Although SRS-GK poses a risk of secondary malignancy, there are some reported cases that underwent malignant transformation without SRS-GK. This suggests that SRS-GK is not the only factor in transformation and is a reasonable therapeutic modality to consider utilizing. Patients and their families should be appropriately counseled on the potential risks of radiation therapy, even for benign lesions like a meningioma.

Long-Term Outcomes for Patients With Atypical or Malignant Meningiomas Treated With or Without Radiation Therapy: A 25-Year Retrospective Analysis of a Single-Institution Experience

Purpose

Atypical (World Health Organization [WHO] grade 2) and malignant (WHO grade 3) meningiomas have high rates of local recurrence, and questions remain about the role of adjuvant radiation therapy (RT) for patients with WHO grade 2 disease. These patients frequently require salvage therapy, and optimal management is uncertain given limited prospective data. We report on the long-term outcomes for patients with atypical and malignant meningiomas treated with surgery and/or RT at our institution.

Methods and Materials

Data were collected through a retrospective chart review for all patients with WHO grade 2 or 3 meningiomas treated with surgery and/or RT at our institution between January 1992 and March 2017. Progression-free survival (PFS) and overall survival (OS) were described using the KaplanMeier estimator. The outcomes in the subgroups were compared with a log-rank test. A Cox proportional hazards model was used for the univariable and multivariable analyses of predictors of PFS.

Results

A total of 66 patients were included in this analysis. The median follow-up was 12.4 years overall and 8.6 years among surviving patients. Fifty-two patients (78.8%) had WHO grade 2 meningiomas, and 14 patients (21.2%) had WHO grade 3 disease. Thirty-six patients (54.5%) were treated with surgery alone, 28 patients (42.4%) with surgery and adjuvant RT, and 2 patients (3%) with RT alone. Median PFS and OS were 3.2 years and 8.8 years, respectively. PFS was significantly improved with adjuvant RT compared with surgery alone (hazard ratio, 0.36; 95% confidence interval, 0.18-0.70). Patients with Ki-67 index >10% showed a trend toward worse PFS compared with patients with Ki-67 ≤10% (hazard ratio, 0.51; 95% confidence interval, 0.25-1.04). No significant differences in PFS or OS were observed with respect to Simpson or WHO grade.

Conclusions

For patients with atypical or malignant meningiomas, adjuvant RT was associated with significantly improved PFS, and Ki-67 index >10% was associated with a trend toward worse PFS. Given the long-term survival, high recurrence rates, and efficacy of salvage therapy, patients with atypical and malignant meningiomas should be monitored systematically long after initial treatment.

Multisession radiosurgery for grade 2 (WHO), high risk meningiomas. A phase II clinical trial

Purpose

Patients suffering from recurrent and residual grade 2 (WHO) meningiomas after subtotal excision should be considered as high-risk groups with an uncertain prognosis. Adjuvant radiotherapy seems to be the best approach to reduce disease progression. The primary aim of this phase II explorative, monocentric, single arm study was to evaluate the safety of adjuvant multisession radiosurgery (mRS) in this group of patients; the efficacy in terms of tumour local control was the secondary endpoint.

Methods

Patients recruited from April 2017 to May 2019 were over 18 years old, had a histologically-documented intracranial recurrent or residual Grade 2 meningioma (WHO 2016) and a KPS > 70. Patients with NF2, concomitant neoplasm or pregnancy were excluded. Descriptive statistics were provided for categorical variables. Progression free survival (PFS) was modelled using the Kaplan–Meier method.

Results

Twenty-four patients were enrolled. All 24 patients underwent mRS: twenty-two patients received 28 Gy in 4 fractions, 2 patients received 24 Gy in 4 Treatment related adverse events (CTCAE 4.3) were limited to grade 2 in 1 patient (4.1%). At a median follow-up of 28 months, 8 patients (33.3%) had disease progression, either out-of-field or infield, compared with the planning target volume. Considering both infield and out-of-field progressions, 3-year PFS was 47% (95% confidence interval, CI, 22–69%); considering only the infield ones, 3-year PFS was 86% (95% CI 55–96%), and local control at last follow-up was 92%.

Conclusion

mRS provides good local control of the tumour volume (TV) and is associated with a low rate of toxicity. These results call for further investigation to confirm favourable outcomes in patients with high-risk meningioma.

Trial information

NCT05081908, October 18, 2021, retrospectively registered.

Identification and Management of Aggressive Meningiomas

Meningiomas are common primary central nervous system tumors derived from the meninges, with management most frequently entailing serial monitoring or a combination of surgery and/or radiation therapy. Although often considered benign lesions, meningiomas can not only be surgically inaccessible but also exhibit aggressive growth and recurrence. In such cases, adjuvant radiation and systemic therapy may be required for tumor control. In this review, we briefly describe the current WHO grading scale for meningioma and provide demonstrative cases of treatment-resistant meningiomas. We also summarize frequently observed molecular abnormalities and their correlation with intracranial location and recurrence rate. We then describe how genetic and epigenetic features might supplement or even replace histopathologic features for improved identification of aggressive lesions. Finally, we describe the role of surgery, radiotherapy, and ongoing systemic therapy as well as precision medicine clinical trials for the treatment of recurrent meningioma.

Adjuvant radiation versus observation with salvage radiation after gross-total resection of WHO grade II meningiomas: a propensity score-adjusted analysis

OBJECTIVE

After gross-total resection (GTR) of a newly diagnosed WHO grade II meningioma, the decision to treat with radiation upfront or at initial recurrence remains controversial. A comparison of progression-free survival (PFS) between observation and adjuvant radiation fails to account for the potential success of salvage radiation, and a direct comparison of PFS between adjuvant and salvage radiation is hampered by strong selection bias against salvage radiation cohorts in which only more aggressive, recurrent tumors are included. To account for the limitations of traditional PFS measures, the authors evaluated radiation failure-free survival (RFFS) between two treatment strategies after GTR: adjuvant radiation versus observation with salvage radiation, if necessary.

METHODS

The authors performed a retrospective review of patients who underwent GTR of newly diagnosed WHO grade II meningiomas at their institution between 1996 and 2019. They assessed traditional PFS in patients who underwent adjuvant radiation, postoperative observation, and salvage radiation. For RFFS, treatment failure was defined as time from initial surgery to failure of first radiation. To assess the association between treatment strategy and RFFS while accounting for potential confounders, a multivariable Cox regression analysis adjusted for the propensity score (PS) and inverse probability of treatment weighted (IPTW) Cox regression analysis were performed.

RESULTS

A total of 160 patients underwent GTR and were included in this study. Of the 121 patients who underwent observation, 32 (26.4%) developed recurrence and required salvage radiation. PFS at 3, 5, and 10 years after observation was 75.1%, 65.6%, and 45.5%, respectively. PFS at 3 and 5 years after salvage radiation was 81.7% and 61.3%, respectively. Of 160 patients, 39 received adjuvant radiation, and 3- and 5-year PFS/RFFS rates were 86.1% and 59.2%, respectively. In patients who underwent observation with salvage radiation, if necessary, the 3-, 5-, and 10-year RFFS rates were 97.7%, 90.3%, and 87.9%, respectively. Both PS and IPTW Cox regression models demonstrated that patients who underwent observation with salvage radiation treatment, if necessary, had significantly longer RFFS (PS model: hazard ratio [HR] 0.21, p < 0.01; IPTW model: HR 0.21, p < 0.01).

CONCLUSIONS

In this retrospective, nonrandomized study, adjuvant radiation after GTR of a WHO II meningioma did not add significant benefit over a strategy of observation and salvage radiation at initial recurrence, if necessary, but results must be considered in the context of the limitations of the study design.