Retrospective analysis of recurrence patterns and clinical outcome of grade II meningiomas following postoperative radiotherapy

SNAP25 as a prognostic marker in transcriptome analysis of meningioma

BACKGROUND

Meningiomas are the most common intracranial tumors and their diagnosis relies mostly on neuroimaging and histology. However, the histology grades cannot predict the outcome exactly and some meningiomas tend to recur after resection of even benign tumors. Therefore, it is necessary to explore prognostic and diagnostic molecular targets.

METHODS

Differential expression analysis between meningiomas and meninges was performed based on the merged data of GSE43290 and GSE84263. Next, we performed gene set enrichment analysis (GSEA), immune cell infiltration analysis, protein-protein interaction analysis, and survival analysis using public data. The expression level of Synaptosome-associated-protein-25kDa (SNAP25) was verified by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting in meningioma tissues.

RESULTS

There were 263 upregulated and 592 downregulated genes identified in meningiomas by differential expression analysis. GSEA results revealed that meningiomas were negatively related to the pathway of soluble N-ethylmaleimide sensitive factor attachment protein receptor interactions in vascular transport and chemokine signaling. SNAP25 was characterized as a hub gene and downregulated in meningiomas. The Kaplan-Meier plot indicated that high expression of SNAP25 is a favorable factor.

CONCLUSION

SNAP25 was downregulated and identified as a potential prognostic marker in meningioma.

Fractionated Radiotherapy With Stereotactic Radiosurgery Boost Controls Gross Disease in Grade 2 Meningioma

OBJECTIVE

Opportunity exists for improved local control rates of grade 2 meningiomas that recur despite maximal surgical resection and adjuvant fractionated radiotherapy (RT). We describe a dose escalation strategy of increasing the total tumor radiation dose by adding a stereotactic radiosurgery (SRS) boost targeting gross disease to fractionated RT.

METHODS

A single-institution retrospective cohort of patients from 2009-2023 with grade 2 meningioma treated with surgical resection, fractionated RT, and SRS boost were evaluated for baseline characteristics, local disease control, and adverse events (AE).

RESULTS

Fourteen meningioma patients were included. Ten patients (71.4%) underwent radiosurgery at initial diagnosis, while 4 patients (28.6%) were treated for recurrent disease. The median fractionated dose was 54 Gy, while the median dose for SRS was 7.5 Gy. Among the 13 patients with follow-up available, median follow-up was 34 months. Three patients (23%) had treatment failures; however, none occurred within the SRS volume and 2 thirds occurred in patients treated for recurrent disease. Eighteen-month progression-free survival was 92.3%, while 18-month overall survival was 100%. Most patients experienced no or mild AEs; however, 3 patients (23%) experienced a high-grade (Common Terminology Criteria for Adverse Events v5.0 grade ≥3) AE including radiation necrosis, seizures, and cognitive decline.

CONCLUSIONS

We found 100% in-field local control at 3 years from an SRS boost to fractionated RT targeting gross disease with an acceptable toxicity profile, suggesting this may be an effective and improved adjuvant treatment strategy in patients with grade 2 meningioma.

Topographic Patterns of Intracranial Meningioma Recurrences-Systematic Review with Clinical Implication

BACKGROUND

While several risk factors for recurrences have been defined, the topographic pattern of meningioma recurrences after surgical resection has been scarcely investigated. The possibility of theoretically predicting the site of recurrence not only allows us to better understand the pathogenetic bases of the disease and consequently to drive the development of new targeted therapies, but also guides the decision-making process for treatment strategies and tailored follow-ups to decrease/prevent recurrence.

METHODS

The authors performed a comprehensive and detailed systematic literature review of the EMBASE and MEDLINE electronic online databases regarding the topographic pattern of recurrence after surgical treatment for intracranial meningiomas. Demographics and histopathological, neuroradiological and treatment data, pertinent to the topography of recurrences, as well as time to recurrences, were extracted and analyzed.

RESULTS

Four studies, including 164 cases of recurrences according to the inclusion criteria, were identified. All studies consider the possibility of recurrence at the previous dural site; three out of four, which are the most recent, consider 1 cm outside the previous dural margin to be the main limit to distinguish recurrences closer to the previous site from those more distant. Recurrences mainly occur within or close to the surgical bed; higher values of proliferation index are associated with recurrences close to the original site rather than within it.

CONCLUSIONS

Further studies, including genomic characterization of different patterns of recurrence, will better clarify the main features affecting the topography of recurrences. A comparison between topographic classifications of intracranial meningioma recurrences after surgery and after radiation treatment could provide further interesting information.

Radiotherapy intensification for atypical and malignant meningiomas: A systematic review

Background

The outcomes of nonbenign (WHO Grades 2 and 3 [G2, G3]) meningiomas are suboptimal and radiotherapy (RT) dose intensification strategies have been investigated. The purpose of this review is to report on clinical practice and outcomes with particular attention to RT doses and techniques.

Methods

The PICO criteria (Population, Intervention, Comparison, and Outcomes) were used to frame the research question, directed at outlining the clinical outcomes in patients with G2-3 meningiomas treated with RT. The same search strategy was run in Embase and MEDLINE and, after deduplication, returned 1 807 records. These were manually screened for relevance and 25 were included.

Results

Tumor outcomes and toxicities are not uniformly reported in the selected studies since different endpoints and time points have been used by different authors. Many risk factors for worse outcomes are described, the most common being suboptimal RT. This includes no or delayed RT, low doses, and older techniques. A positive association between RT dose and progression-free survival (PFS) has been highlighted by analyzing the studies in this review (10/25) that report the same endpoint (5y-PFS).

Conclusions

This literature review has shown that standard practice RT leads to suboptimal tumor control rates in G2-3 meningiomas, with a significant proportion of disease recurring after a relatively short follow-up. Randomized controlled trials are needed in this setting to define the optimal RT approach. Given the increasing data to suggest a benefit of higher RT doses for high-risk meningiomas, novel RT technologies with highly conformal dose distributions are preferential to achieve optimal target coverage and organs at risk sparing.

Beyond the Surgical Margin: Patterns of Recurrence in World Health Organization Grade 2 Intracranial Meningiomas

OBJECTIVE

To characterize and classify the location of recurrence in surgically resected World Health Organization (WHO) grade 2 intracranial meningiomas that did not receive adjuvant radiation and compare the recurrence pattern of those who underwent gross total resection (GTR) versus subtotal resection (STR).

METHODS

We performed a retrospective review of patients who underwent surgical resection of a newly diagnosed WHO grade 2 meningioma at our institution between 1996 and 2019. Patients who were observed postoperatively without adjuvant radiation and subsequently developed a recurrence were included in the study. All patients who received adjuvant therapy were excluded. Recurrence was defined as any evidence of radiographic progression on postoperative surveillance magnetic resonance imaging. Location of recurrence was categorized as follows: 1) central-growth observed inside the area of the previously resected tumor more than 1 cm inside the original tumor margin; 2) marginal-growth observed within 1 cm (inside or outside) of the original tumor margin; and 3) remote-growth observed >1 cm outside the original tumor margin. Patterns of recurrence were evaluated by 2 observers after coregistering preoperative and postoperative magnetic resonance imaging, and any differences were reconciled by discussion.

RESULTS

A total of 22 patients matched the inclusion criteria. Twelve (55%) underwent GTR, and 10 (45%) underwent STR. In 12 patients in whom GTR was achieved, the mean preoperative tumor volume was 50.6 cm3, with 5 (41.7%) in a skull base location. The average time to recurrence for these tumors was 22.7 months, with a mean recurrent tumor volume of 9.0 cm3. Ten patients (83.3%) had central recurrence, 11 patients (91.7%) had marginal recurrence, and only 4 patients (33.3%) had remote recurrence. In 10 patients in whom STR was achieved, mean preoperative tumor volume was 44.8 cm3, with 7 (70.0%) in a skull base location. The average time to recurrence for these tumors was 23.0 months, with a mean recurrent tumor volume of 21.8 cm3. Of these 10 patients, 9 (90.0%) had central recurrence, all 10 (100.0%) had marginal recurrence, and only 4 (40.0%) patients had remote recurrence.

CONCLUSIONS

The present study evaluating patterns of recurrence for WHO grade 2 meningiomas after surgical resection (GTR or STR) showed that recurrence occurred centrally and/or at the original tumor margin, with only a few recurring >1 cm outside the original tumor margin. The results of this study suggest that treatment, whether initial surgical resection or adjuvant radiation, may benefit from including at least a 1-cm dural margin when safe, to optimize tumor control, but further clinical study is needed.

Primary Skull Base Chordomas: A Clinicopathological Analysis of 94 Patients

OBJECTIVE

To investigate prognostic factors in patients with primary skull base chordoma (PSBC) to guide future therapeutic advances.

METHODS

This retrospective cohort study of 94 PSBC patients was conducted in 2 institutions from January 2006 to December 2013. Independent predictors for progression-free survival (PFS) and overall survival were established with multivariate Cox regression analysis.

RESULTS

Age (P = 0.006), extent of resection (P = 0.037), and radiotherapy (RT) (P = 0.027) were established as independent predictors for PFS in PSBC patients. Similarly, age (P = 0.002), extent of resection (P = 0.048), and RT (P = 0.015) were established as independent predictors for overall survival. Meta-analysis manifested that lower MIB-1 correlated with longer PFS in skull base chordoma patients (P < 0.001). RT doubled the 5-year PFS rate from 28.6 ± 12.1% to 61.6 ± 10.7% (P = 0.031) and increased the 5-year overall survival rate from 54.5 ± 13.8% to 84.2 ± 8.4% (P = 0.020) in the subtotal resection/partial resection and MIB-1 labeling index (STR/PR+MIB-1 LI) <2% subgroup. In contrast, in the STR/PR+MIB-1 LI ≥2% subgroup, the survival benefit of RT remained uncertain. Further analysis revealed no survival difference between different RT modalities in STR/PR PSBC patients.

CONCLUSIONS

In PSBC patients, age, extent of resection, and adjuvant RT all are independent predictors for PFS. Lower MIB-1 LI is associated with longer PFS in PSBC patients. Adjuvant RT is necessary for PSBC patients who undergo STR/PR with MIB-1 LI <2%. Patients who undergo GTR or STR/PR with MIB-1 LI ≥2% seem nonresponsive to RT.

The "Combo" radiotherapy treatment for high-risk grade 2 meningiomas: dose escalation and initial safety and efficacy analysis

PURPOSE

The subgroup "high-risk" WHO grade 2 (hRG2) meningiomas may benefit from adjuvant radiation therapy (RT), but results are still suboptimal with high rates of local progression. A dose escalation using high-conformal RT techniques needs to be evaluated in terms of efficacy and safety. We report the results of a dose-escalation study, named "Combo-RT", combining Intensity Modulated Radiotherapy (IMRT) or Volumetric Arc Therapy (VMAT) with Hypofractionated Stereotactic Radiotherapy (hSRT) boost.

PATIENTS AND METHODS

From November 2015 to January 2019, we prospectively enrolled 16 patients with hRG2. Seven patients had subtotal resection (STR) and 9 patients had a recurrent tumor. All patients received Combo-RT: LINAC-IMRT/ VMAT on the surgical bed and CyberKnife-hSRT boost on residual/recurrent meningioma Toxicity and initial efficacy were evaluated.

RESULTS

The median age was 62 years (range, 31-80 years). The median cumulative dose delivered was 46 Gy For IMRT or VMAT and 15 Gy in 3 fractions at a median isodose line of 77% for hSRT. The median cumulative BED and EQD2 were 108.75 Gy and 72.5 Gy respectively. 3-year-PFS was 75% for the whole cohort,100% for patients with STR, and 55.5% for recurrent patients. Negligible toxicities, and stable or improved symptoms during long-term follow-up were observed. Salvage treatment for recurrence was an independent predictor of treatment failure (P = 0.025).

CONCLUSIONS

With the limitation of a small series of patients, our results suggest that a dose escalation for hRG2 meningiomas, using a Combo-RT approach, is safe and particularly effective in the subgroup of patients with STR. Further studies are warranted.