How proton therapy fits into the management of adult intracranial tumors

Intracranial tumors include a challenging array of primary and secondary parenchymal and extra-axial tumors which cause neurologic morbidity consequential to location, disease extent, and proximity to critical neurologic structures. Radiotherapy can be used in the definitive, adjuvant, or salvage setting either with curative or palliative intent. Proton therapy (PT) is a promising advance due to dosimetric advantages compared to conventional photon radiotherapy with regards to normal tissue sparing, as well as distinct physical properties, which yield radiobiologic benefits. In this review, the principles of efficacy and safety of PT for a variety of intracranial tumors are discussed, drawing upon case series, retrospective and prospective cohort studies, and randomized clinical trials. This manuscript explores the potential advantages of PT, including reduced acute and late treatment-related side effects and improved quality of life. The objective is to provide a comprehensive review of the current evidence and clinical outcomes of PT. Given the lack of consensus and directives for its utilization in patients with intracranial tumors, we aim to provide a guide for its judicious use in clinical practice.

Single fraction and hypofractionated radiosurgery for perioptic meningiomas-tumor control and visual outcomes: a systematic review and meta-analysis

Perioptic meningiomas, defined as those that are less than 3 mm from the optic apparatus, are challenging to treat with stereotactic radiosurgery (SRS). Tumor control must be weighed against the risk of radiation-induced optic neuropathy (RION), as both tumor progression and RION can lead to visual decline. We performed a systematic review and meta-analysis of single fraction SRS and hypofractionated radiosurgery (hfRS) for perioptic meningiomas, evaluating tumor control and visual preservation rates. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we reviewed articles published between 1968 and December 8, 2022. We retained 5 studies reporting 865 patients, 438 cases treated in single fraction, while 427 with hfRS. For single fraction SRS, the overall rate of tumor control was 95.1%, with actuarial rates at 5 and 10 years of 96% and 89%, respectively; tumor progression was 7.7%. The rate of visual stability was 90.4%, including visual improvement in 29.3%. The rate of visual decline was 9.6%, including blindness in 1.2%. For hfRS, the overall rate of tumor control was 95.6% (range 92.1-99.1, p < 0.001); tumor progression was 4.4% (range 0.9-7.9, p = 0.01). Overall rate of visual stability was 94.9% (range 90.9-98.9, p < 0.001), including visual improvement in 22.7% (range 5.0-40.3, p = 0.01); visual decline was 5.1% (range 1.1-9.1, p = 0.013). SRS is an effective and safe treatment option for perioptic meningiomas. Both hypofractionated regimens and single fraction SRS can be considered.

Stereotactic Radiosurgery for Intracranial Meningiomas

Meningiomas are thought to originate from the meningothelial cells of the arachnoid mater and are the most common primary brain tumor in adults. Histologically confirmed meningiomas occur with an incidence of 9.12/100,000 population and account for 39% of all primary brain tumors and 54.5% of all non-malignant brain tumors. Risk factors for meningioma include age 65 years and older, female gender, African-American race, history of exposure to head and neck ionizing radiation, and certain genetic disorders such as neurofibromatosis II. Intracranial meningiomas are the most commonly benign, WHO Grade I neoplasms. Atypical and anaplastic are considered malignant lesions.

Innovative treatments for meningiomas

Multi-recurrent high-grade meningiomas remain an unmet medical need in neuro-oncology when iterative surgeries and radiation therapy sessions fail to control tumor growth. Nevertheless, the last 10years have been marked by multiple advances in the comprehension of meningioma tumorigenesis via the discovery of new driver mutations, the identification of activated intracellular signaling pathways, and DNA methylation analyses, providing multiple potential therapeutic targets. Today, Anti-VEGF and mTOR inhibitors are the most used and probably the most active drugs in aggressive meningiomas. Peptide radioactive radiation therapy aims to target SSTR2A receptors, which are strongly expressed in meningiomas, but have an insufficient effect in most aggressive meningiomas, requiring the development of new techniques to increase the dose applied to the tumor. Based on the multiple potential intracellular targets, multiple targeted therapy clinical trials targeting Pi3K-Akt-mTOR and MAP kinase pathways as well as cell cycle and particularly, cyclin D4-6 are ongoing. Recently discovered driver mutations, SMO, Akt, and PI3KCA, offer new targets but are mostly observed in benign meningiomas, limiting their clinical relevance mainly to rare aggressive skull base meningiomas. Therefore, NF2 mutation remains the most frequent mutation and main challenging target in high-grade meningioma. Recently, inhibitors of focal adhesion kinase (FAK), which is involved in tumor cell adhesion, were tested in a phase 2 clinical trial with interesting but insufficient activity. The Hippo pathway was demonstrated to interact with NF2/Merlin and could be a promising target in NF2-mutated meningiomas with ongoing multiple preclinical studies and a phase 1 clinical trial. Recent advances in immune landscape comprehension led to the proposal of the use of immunotherapy in meningiomas. Except in rare cases of MSH2/6 mutation or high tumor mass burden, the activity of PD-1 inhibitors remains limited; however, its combination with various radiation therapy modalities is particularly promising. On the whole, therapeutic management of high-grade meningiomas is still challenging even with multiple promising therapeutic targets and innovations.

Hypofractionated Radiosurgery for Large or in Critical-Site Intracranial Meningioma: Results of a Phase 2 Prospective Study

PURPOSE

Radiosurgery is a well-known, safe, and effective technique used in the treatment of intracranial meningiomas. However, single-fraction radiosurgery can lead to high toxicity rates when large-volume or critically located lesions are targeted. Multisession-also called hypofractionated-radiosurgery (hypo-RS) might overcome these limitations. Accordingly, we carried out a prospective phase 2 trial, aiming to establish whether a fractionated RS schedule of 25 Gy in 5 fractions would be safe and effective in treating large (≥ 3 cm) and/or critically located (<3 mm from critical structures) grade 1 intracranial meningiomas. The main aim was to evaluate the safety of hypo-RS in terms of absence of adverse events. The secondary aim was to evaluate tumor response in terms of local control, defined as stability or reduction of lesion volume.

METHODS AND MATERIALS

We prospectively enrolled patients with diagnoses of grade 1 meningiomas, large size and/or critically located lesions, either histologically diagnosed or imaging defined. Additional inclusion criteria were signed informed consent, an age of ≥18 years, and Karnofsky Performance Status ≥70.

RESULTS

Between 2011 and 2016, 178 patients were consecutively enrolled. The median follow-up was 53 months (range, 4-101 months). Overall, the toxicity rate was 12.7% (21 of 166 patients). At a 5-year minimum follow-up, the patients' toxicity rates were 11.7 % (9 of 77 patients). Symptom evaluation at both 3-year and last follow-up showed an improvement in most of the patients. Five-year local tumor control was 97% (95% confidence interval, 92%-99%).

CONCLUSIONS

Hypo-RS schedule of 25 Gy in 5 fractions is a well-tolerated option in the treatment of large-volume and/or critically located benign meningiomas. Early results suggest favorable local control, although longer-term follow-up is needed.

Stereotactic Radiosurgery for Benign Cavernous Sinus Meningiomas: A Multicentre Study and Review of the Literature

Simple Summary

Meningiomas are the most common tumours of the central nervous system (CNS). Despite their benign histology, proximity to critical neurovascular structures may lead to significant morbidity with tumour growth. This is the case for cavernous sinus meningiomas (CSMs), as their growth may surround critical neuro-vascular structures and cause significant morbidity. Radical microsurgical resection carries a high risk of additional neurological deficits, as well as the risk of death. Current management of these tumours, where treatment is indicated, has moved away from radical surgery towards radiotherapy/radiosurgery. This is particularly the case for patients who have residual or recurring tumours after previous surgery. There are many reports that describe the effectiveness of using stereotactic radiosurgery (SRS) for CSMs; however, large cohort analyses are lacking. This multicentre analysis reports the outcome data of over 1000 patients with CSMs who were treated with SRS. SRS shows a high local tumour control rate with few complications. These results agree with previous reports in the literature. SRS is a valuable primary or adjuvant treatment option for CSMs.

Abstract

Cavernous sinus meningiomas (CSMs) remain a surgical challenge due to the intimate involvement of their contained nerves and blood vessels. Stereotactic radiosurgery (SRS) is a safe and effective minimally invasive alternative for the treatment of small- to medium-sized CSMs. Objective: To assess the medium- to long-term outcomes of SRS for CSMs with respect to tumour growth, prevention of further neurological deterioration and improvement of existing neurological deficits. This multicentric study included data from 15 European institutions. We performed a retrospective observational analysis of 1222 consecutive patients harbouring 1272 benign CSMs. All were treated with Gamma Knife stereotactic radiosurgery (SRS). Clinical and imaging data were retrieved from each centre and entered into a common database. All tumours with imaging follow-up of less than 24 months were excluded. Detailed results from 945 meningiomas (86%) were then analysed. Clinical neurological outcomes were available for 1042 patients (85%). Median imaging follow-up was 67 months (mean 73.4, range 24–233). Median tumour volume was 6.2 cc (+/−7), and the median marginal dose was 14 Gy (+/−3). The post-treatment tumour volume decreased in 549 (58.1%), remained stable in 336 (35.6%) and increased in only 60 lesions (6.3%), yielding a local tumour control rate of 93.7%. Only 27 (2.8%) of the 60 enlarging tumours required further treatment. Five- and ten-year actuarial progression-free survival (PFS) rates were 96.7% and 90.1%, respectively. Tumour control rates were higher for women than men (p = 0.0031), and also for solitary sporadic meningiomas (p = 0.0201). There was no statistically significant difference in outcome for imaging-defined meningiomas when compared with histologically proven WHO Grade-I meningiomas (p = 0.1212). Median clinical follow up was 61 months (mean 64, range 6–233). Permanent morbidity occurred in 5.9% of cases at last follow-up. Stereotactic radiosurgery is a safe and effective method for treating benign CSM in the medium term to long term.

Clinical outcomes of benign brain tumors treated with single fraction LINAC-based stereotactic radiosurgery: Experience of a single institute

Objectives

Accelerator-based stereotactic radiosurgery (SRS) is a noninvasive and effective treatment modality widely used for benign brain tumors. This study aims to report 20-year treatment outcomes in our institute.

Materials and Methods

From May 2001 to December 2020, 127 patients treated with LINAC-based single-fraction SRS for their benign brain lesions were included. A neurosurgeon and two radiation oncologists retrospectively reviewed all data. Computed tomography (CT) simulation was performed after head-frame fixation under local anesthesia. All planning CT images were co-registered and fused with gadolinium-enhanced magnetic resonance imaging taken within 3 months for lesions targeting and critical organs delineation. The marginal dose was prescribed at 60%-90% isodose lines, respectively, to cover ≥95% planning target volume. Outcome evaluations included clinical tumor control rate (TCR), defined as the need for salvage therapy, and radiological response, defined as no enlargement of >2 cm in the maximal diameter. Overall survival (OS) and adverse reaction (defined according to CTCAE 5.0) were also analyzed.

Results

The present study included 76 female and 51 male patients for analysis. The median age was 59 years (range, 20-88 years). Their diagnoses were vestibular schwannoma (VS, n = 54), nonvestibular cranial nerve schwannoma (n = 6), meningioma (n = 50), and pituitary adenoma (n = 17). Totally 136 lesions were treated in a single fraction, predominantly skull base tumors, accounting for 69.1%. Median and mean follow-up duration was 49 and 61 months (range, 1-214 months), Overall TCR was 92.9%. The 5-year disease-specific TCR for VS, nonvestibular schwannoma, meningioma, and pituitary adenoma were 97.4%, 91.7%, 93.8%, and 83.3%. Salvage therapy was indicated for eight patients at 4-110 months after SRS. Among symptomatic patients, post-SRS symptom(s) was improved, stable, and worse in 68.2%, 24.3%, and 3.6%, respectively. Radiological response rate for 111 evaluable patients was 94.6% (shrinkage, 28.8%; stable, 65.8%). OS was 96.1% without treatment-related mortality. One patient with post-SRS cranial nerve injury (0.8%, involving the trigeminal nerve, grade 2 toxicities). No grade 3-4 acute or late toxicity was found.

Conclusion

Our results suggested that LINAC-based SRS effectively controls tumor growth and tumor-related neurological symptoms for patients with benign brain tumors. SRS is less aggressive, associated with low neurological morbidity and no mortality. Continuous follow-up is indicated to conclude longer outcomes.

MRI radiomics in the prediction of the volumetric response in meningiomas after gamma knife radiosurgery

PURPOSE

This report presents the first investigation of the radiomics value in predicting the meningioma volumetric response to gamma knife radiosurgery (GKRS).

METHODS

The retrospective study included 93 meningioma patients imaged by three Tesla MRI. Tumor morphology was quantified by calculating 337 shape, first- and second-order radiomic features from MRI obtained before GKRS. Analysis was performed on original 3D MR images and after their laplacian of gaussian (LoG), logarithm and exponential filtering. The prediction performance was evaluated by Pearson correlation, linear regression and ROC analysis, with meningioma volume change per month as the outcome.

RESULTS

Sixty calculated features significantly correlated with the outcome. The feature selection based on LASSO and multivariate regression started from all available 337 radiomic and 12 non-radiomic features. It selected LoG-sigma-1-0-mm-3D_firstorder_InterquartileRange and logarithm_ngtdm_Busyness as the predictively most robust and non-redundant features. The radiomic score based on these two features produced an AUC = 0.81. Adding the non-radiomic karnofsky performance status (KPS) to the score has increased the AUC to 0.88. Low values of the radiomic score defined a homogeneous subgroup of 50 patients with consistent absence (0%) of tumor progression.

CONCLUSION

This is the first report of a strong association between MRI radiomic features and volumetric meningioma response to radiosurgery. The clinical importance of the early and reliable prediction of meningioma responsiveness to radiosurgery is based on its potential to aid individualized therapy decision making.

Meningiomas

Meningiomas arise in various locations. Convexity tumors are relatively simple to remove. Skull base tumors and tumors adjacent to the major cerebral veins and venous sinuses can be very difficult to extirpate. Attempts at radical resection can lead to serious morbidity. The combination of bulk reduction using microsurgery followed by GKNS gives greatly improved survival and very low morbidity. With smaller tumors, GKNS may be used as the primary treatment. Increasing numbers of asymptomatic meningiomas are demonstrated either as an unexpected finding or as a residual or recurrent tumor after surgery. In all of these situations, GKNS gives a better result than observation or reoperation.

Long-term outcomes of stereotactic radiosurgery for skull base tumors involving the cavernous sinus

PURPOSE

Stereotactic radiosurgery (SRS) is an effective and less invasive therapeutic option for cavernous sinus (CS) tumors. However, its long-term effectiveness and neurological outcomes have yet to be fully elucidated. We aimed to examine the long-term outcomes of SRS for CS tumors.

METHODS

Overall, a cohort of 113 patients with benign CS tumors, including 91 with meningioma, 14 with trigeminal schwannoma (TS), and eight with cavernous hemangioma, treated with SRS at our institution from 1990 to 2018, was included. Tumor control and functional preservation/recovery were evaluated in detail.

RESULTS

The median post-SRS follow-up period was 77 months (interquartile range, 39-177). Progression-free survival (PFS) was 97% at 5 years, 89% at 10 years, and 87% at 15 years for the entire cohort; 96% at 5 years and 87% at 10 years for meningiomas; and 100% at 10 years for the other tumors. No significant difference was observed between meningiomas and non-meningiomas (log-rank test, p = 0.107). Improvement in cranial nerve (CN) function was observed in 35 (27%) patients. TSs tended to show CN improvements more often than meningiomas did (total improvements, 62% vs. 23%; p = 0.004; eye movement function, 100% vs. 20%; p = 0.002). CN deterioration or development of new CN deficits was observed in 11 (10%) patients.

CONCLUSION

SRS provides good tumor control and acceptable long-term outcome with sufficient preservation of CN function in patients with benign CS tumors.

Management of cavernous sinus meningiomas: Consensus statement on behalf of the EANS skull base section

Introduction

The evolution of cavernous sinus meningiomas (CSMs) might be unpredictable and the efficacy of their treatments is challenging due to their indolent evolution, variations and fluctuations of symptoms, heterogeneity of classifications and lack of randomized controlled trials. Here, a dedicated task force provides a consensus statement on the overall management of CSMs.

Research question

To determine the best overall management of CSMs, depending on their clinical presentation, size, and evolution as well as patient characteristics.

Material and methods

Using the PRISMA 2020 guidelines, we included literature from January 2000 to December 2020. A total of 400 abstracts and 77 titles were kept for full-paper screening.

Results

The task force formulated 8 recommendations (Level C evidence). CSMs should be managed by a highly specialized multidisciplinary team. The initial evaluation of patients includes clinical, ophthalmological, endocrinological and radiological assessment. Treatment of CSM should involve experienced skull-base neurosurgeons or neuro-radiosurgeons, radiation oncologists, radiologists, ophthalmologists, and endocrinologists.

Discussion and conclusion

Radiosurgery is preferred as first-line treatment in small, enclosed, pauci-symptomatic lesions/in elderly patients, while large CSMs not amenable to resection or WHO grade II-III are candidates for radiotherapy. Microsurgery is an option in aggressive/rapidly progressing lesions in young patients presenting with oculomotor/visual/endocrinological impairment. Whenever surgery is offered, open cranial approaches are the current standard. There is limited experience reported about endoscopic endonasal approach for CSMs and the main indication is decompression of the cavernous sinus to improve symptoms. Whenever surgery is indicated, the current trend is to offer decompression followed by radiosurgery.

•

A thorough evaluation of cavernous sinus meningiomas by a multidisciplinary team is mandatory.

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Microsurgery should be considered for aggressive lesions in young patients.

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Extended endoscopic approaches can be effective when combined with radiotherapy.

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Stereotaxic radiotherapy and stereotaxic radiosurgery offer excellent tumour control in small/asymptomatic lesions .

Surgery for clinoidal meningiomas with cavernous sinus extension: Near-total excision and chiasmopexy

BACKGROUND

The main factors limiting the extent of resection for clinoidal meningiomas are cavernous sinus extension and vessel adventitia involvement. The proximity to the optic apparatus and the risk of radiation-induced optic neuropathy often prevents many surgeons from proposing adjuvant radiosurgery.

METHOD

We describe a simple technical solution that is to place a fat graft between the optic apparatus and the residual tumor to maintain the distance gained at surgery and facilitates the identification of anatomic structures.

CONCLUSION

This technique allows to deliver optimal therapeutic doses to the residue reduces the dose received by the optic nerve below 8 Gy.

Surgical management of anterior clinoidal meningiomas: consensus statement on behalf of the EANS skull base section

BACKGROUND

The optimal management of clinoidal meningiomas (CMs) continues to be debated.

METHODS

We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of these tumors. The data from the literature along with contemporary practice patterns were discussed within the task force to generate consensual recommendations.

RESULTS AND CONCLUSION

This article represents the consensus opinion of the task force regarding pre-operative evaluations, patient's counselling, surgical classification, and optimal surgical strategy. Although this analysis yielded only Class B evidence and expert opinions, it should guide practitioners in the management of patients with clinoidal meningiomas and might form the basis for future clinical trials.

Stereotactic radiosurgery for clinoid meningiomas: a multi-institutional study

PURPOSE

Resection of clinoid meningiomas can be associated with significant morbidity. Experience with stereotactic radiosurgery (SRS) for clinoid meningiomas remains limited. We studied the safety and effectiveness of SRS for clinoid meningiomas.

METHODS

From twelve institutions participating in the International Radiosurgery Research Foundation, we pooled patients treated with SRS for radiologically suspected or histologically confirmed WHO grade I clinoid meningiomas.

RESULTS

Two hundred seven patients (median age: 56 years) underwent SRS for clinoid meningiomas. Median treatment volume was 8.02 cm³, and 87% of tumors were immediately adjacent to the optic apparatus. The median tumor prescription dose was 12 Gy, and the median maximal dose to the anterior optic apparatus was 8.5 Gy. During a median post-SRS imaging follow-up of 51.1 months, 7% of patients experienced tumor progression. Greater margin SRS dose (HR = 0.700, p = 0.007) and pre-SRS radiotherapy (HR = 0.004, p < 0.001) were independent predictors of better tumor control. During median visual follow-up of 48 months, visual function declined in 8% of patients. Pre-SRS visual deficit (HR = 2.938, p = 0.048) and maximal radiation dose to the optic apparatus of ≥ 10 Gy (HR = 11.297, p = 0.02) independently predicted greater risk of post-SRS visual decline. Four patients experienced new post-SRS cranial nerve V neuropathy.

CONCLUSIONS

SRS allows durable control of clinoid meningiomas and visual preservation in the majority of patients. Greater radiosurgical prescription dose is associated with better tumor control. Radiation dose to the optic apparatus of ≥ 10 Gy and visual impairment before the SRS increase risk of visual deterioration.

Does the Timing of Radiosurgery after Grade 1 Meningioma Resection Affect Long-Term Outcomes?

BACKGROUND

Meningiomas are the most common benign intracranial tumors. Gamma Knife® stereotactic radiosurgery (GKSRS) has become a preferred management for recurrent or residual meningiomas. This study focuses on the relationship between tumor control and the time interval between resection of a World Health Organization (WHO) grade 1 meningioma and GKSRS.

METHODS

This single institution retrospective analysis reviewed our experience in 238 patients who underwent GKSRS after a pathologically confirmed WHO grade 1 meningioma resection. The median follow-up was 7.4 years. The median aggregate tumor volume at GKSRS was 6 cm3 and a median margin dose of 13 Gy was utilized. Neurological symptoms were evident in 60% of patients at the time of procedure.

RESULTS

Overall actuarial tumor control rates achieved were 91.3% at 5 years, 83.4% at 10 years, and 76% at 15 years. There were 35 patients (15%) who developed tumor progression within or directly adjacent to the GKSRS treatment field. The median time until progression was 6.3 years. The duration between surgical intervention and GKSRS did not show statistical significance at 3 months (p = 0.9), 6 months (p = 0.8), 12 months (p = 0.5), or 24 months (p = 0.9). Fifteen patients (6%) had tumor progression at an anatomically distinct location outside the GKSRS target volume. Neurological symptomatic improvement was more likely with early radiosurgery intervention (p = 0.007).

CONCLUSION

Postoperative GKSRS was associated with excellent long-term tumor control for WHO grade 1 meningiomas, regardless of the interval after initial surgery. In addition, earlier radiosurgery was associated with superior symptom improvement.

Stereotactic Radiosurgery for Perioptic Meningiomas: An International, Multicenter Study

BACKGROUND

Stereotactic radiosurgery (SRS) is increasingly used for management of perioptic meningiomas.

OBJECTIVE

To study the safety and effectiveness of SRS for perioptic meningiomas.

METHODS

From 12 institutions participating in the International Radiosurgery Research Foundation (IRRF), we retrospectively assessed treatment parameters and outcomes following SRS for meningiomas located within 3 mm of the optic apparatus.

RESULTS

A total of 438 patients (median age 51 yr) underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) perioptic meningiomas. Median treatment volume was 8.01 cm3. Median prescription dose was 12 Gy, and median dose to the optic apparatus was 8.50 Gy. A total of 405 patients (93%) underwent single-fraction SRS and 33 patients (7%) underwent hypofractionated SRS. During median imaging follow-up of 55.6 mo (range: 3.15-239 mo), 33 (8%) patients experienced tumor progression. Actuarial 5-yr and 10-yr progression-free survival was 96% and 89%, respectively. Prescription dose of ≥12 Gy (HR: 0.310; 95% CI [0.141-0.679], P = .003) and single-fraction SRS (HR: 0.078; 95% CI [0.016-0.395], P = .002) were associated with improved tumor control. A total of 31 (10%) patients experienced visual decline, with actuarial 5-yr and 10-yr post-SRS visual decline rates of 9% and 21%, respectively. Maximum dose to the optic apparatus ≥10 Gy (HR = 2.370; 95% CI [1.086-5.172], P = .03) and tumor progression (HR = 4.340; 95% CI [2.070-9.097], P < .001) were independent predictors of post-SRS visual decline.

CONCLUSION

SRS provides durable tumor control and quite acceptable rates of vision preservation in perioptic meningiomas. Margin dose of ≥12 Gy is associated with improved tumor control, while a dose to the optic apparatus of ≥10 Gy and tumor progression are associated with post-SRS visual decline.

Meningiomas in Gynecology and Reproduction: an Updated Overview for Clinical Practice

There is various evidence to suggest a relationship between female hormones and meningiomas; as clinicians, we often come to face challenging situations involving female patients diagnosed with meningiomas during the post-pubertal phases of their life. We aimed to review the specific circumstances (pregnancy, postpartum, hormonal contraception and hormone replacement therapy, gender-affirming hormonal treatment) clinicians might come to face during their daily clinical practice, given the absence of available guidelines. We therefore conducted a narrative review on articles found in PubMed and Embase databases using appropriate keywords. Ninety-six relevant articles were included. The available evidence on managing meningiomas in post-pubertal women often implies personal strategies, highlighting the lack of a unified approach. The knowledge of the biological links between female hormones and meningiomas is fundamental to correctly counsel patients in various life phases. Prospective randomized studies are required to improve available guidelines on how to best manage meningiomas in female post-pubertal patients.

Stereotactic Radiosurgery for Intracranial Noncavernous Sinus Benign Meningioma: International Stereotactic Radiosurgery Society Systematic Review, Meta-Analysis and Practice Guideline

BACKGROUND

Stereotactic radiosurgery (SRS) for benign intracranial meningiomas is an established treatment.

OBJECTIVE

To summarize the literature and provide evidence-based practice guidelines on behalf of the International Stereotactic Radiosurgery Society (ISRS).

METHODS

Articles in English specific to SRS for benign intracranial meningioma, published from January 1964 to April 2018, were systematically reviewed. Three electronic databases, PubMed, EMBASE, and the Cochrane Central Register, were searched.

RESULTS

Out of the 2844 studies identified, 305 had a full text evaluation and 27 studies met the criteria to be included in this analysis. All but one were retrospective studies. The 10-yr local control (LC) rate ranged from 71% to 100%. The 10-yr progression-free-survival rate ranged from 55% to 97%. The prescription dose ranged typically between 12 and 15 Gy, delivered in a single fraction. Toxicity rate was generally low.

CONCLUSION

The current literature supporting SRS for benign intracranial meningioma lacks level I and II evidence. However, when summarizing the large number of level III studies, it is clear that SRS can be recommended as an effective evidence-based treatment option (recommendation level II) for grade 1 meningioma.

Intraoperative MRI for the microsurgical resection of meningiomas close to eloquent areas or dural sinuses: patient series

BACKGROUND

Meningiomas are the most commonly encountered nonglial primary intracranial tumors. The authors report on the usefulness of intraoperative magnetic resonance imaging (iMRI) during microsurgical resection of meningiomas located close to eloquent areas or dural sinuses and on the feasibility of further radiation therapy.

OBSERVATIONS

Six patients benefited from this approach. The mean follow-up period after surgery was 3.3 (median 3.2, range 2.1–4.6) years. Five patients had no postoperative neurological deficit, of whom two with preoperative motor deficit completely recovered. One patient with preoperative left inferior limb deficit partially recovered. The mean interval between surgery and radiation therapy was 15.8 (median 16.9, range 1.4–40.5) months. Additional radiation therapy was required in five cases after surgery. The mean preoperative tumor volume was 38.7 (median 27.5, range 8.6–75.6) mL. The mean postoperative tumor volume was 1.2 (median 0.8, range 0–4.3) mL. At the last follow-up, all tumors were controlled.

LESSONS

The use of iMRI was particularly helpful to (1) decide on additional tumor resection according to iMRI findings during the surgical procedure; (2) evaluate the residual tumor volume at the end of the surgery; and (3) judge the need for further radiation and, in particular, the feasibility of single-fraction radiosurgery.

ESTRO ACROP guideline for target volume delineation of skull base tumors

BACKGROUND AND PURPOSE

For skull base tumors, target definition is the key to safe high-dose treatments because surrounding normal tissues are very sensitive to radiation. In the present work we established a joint ESTRO ACROP guideline for the target volume definition of skull base tumors.

MATERIAL AND METHODS

A comprehensive literature search was conducted in PubMed using various combinations of the following medical subjects headings (MeSH) and free-text words: "radiation therapy" or "stereotactic radiosurgery" or "proton therapy" or "particle beam therapy" and "skull base neoplasms" "pituitary neoplasms", "meningioma", "craniopharyngioma", "chordoma", "chondrosarcoma", "acoustic neuroma/vestibular schwannoma", "organs at risk", "gross tumor volume", "clinical tumor volume", "planning tumor volume", "target volume", "target delineation", "dose constraints". The ACROP committee identified sixteen European experts in close interaction with the ESTRO clinical committee who analyzed and discussed the body of evidence concerning target delineation.

RESULTS

All experts agree that magnetic resonance (MR) images with high three-dimensional spatial accuracy and tissue-contrast definition, both T2-weighted and volumetric T1-weighted sequences, are required to improve target delineation. In detail, several key issues were identified and discussed: i) radiation techniques and immobilization, ii) imaging techniques and target delineation, and iii) technical aspects of radiation treatments including planning techniques and dose-fractionation schedules. Specific target delineation issues with regard to different skull base tumors, including pituitary adenomas, meningiomas, craniopharyngiomas, acoustic neuromas, chordomas and chondrosarcomas are presented.

CONCLUSIONS

This ESTRO ACROP guideline achieved detailed recommendations on target volume definition for skull base tumors, as well as comprehensive advice about imaging modalities and radiation techniques.

Comparison of clinical outcomes in patients who underwent Gamma Knife radiosurgery for parasellar meningiomas with or without prior surgery

Background

Parasellar meningioma is a common benign tumour in brain. Both surgery and radiosurgery are important treatment modalities for this tumour. The study was designed to investigate whether prior surgery would affect treatment outcomes of patients with parasellar meningiomas after management with Gamma Knife radiosurgery.

Methods

A total of 93 patients who received Gamma Knife surgery were included in this retrospective study. There were 30 males and 63 females, with a median age of 48.6 years (range, 15.2–78.7 years). Prior surgery was performed in 45 patients. The median tumor volume was 5.02 cm³ (range 1.07–35.46 cm³) and median marginal dose was 12 Gy (range 10–15 Gy). The mean imaging follow-up and clinical follow-up periods were 40.7 and 52.7 months, respectively.

Results

In the group without prior surgery, 31 patients had improvement of preexisting symptoms; and in the group with prior surgery, 20 patients were noted to improve. The difference in symptom improvement between the two groups reached statistical significance (P = 0.009). Patients with prior surgery were more likely to have stable symptoms after Gamma Knife surgery (P = 0.012). Tumor recurrence was reported in 8 patients out of 45 patients with prior surgery, and 3 patients out of 48 patents without prior surgery (P = 0.085). After Gamma Knife surgery, 5 and 4 patients in two groups developed new neurological symptoms, respectively (P = 0.651). Cox regression analysis identified follow-up period as prognostic factor of progression-free survival. Ordinal logistic regression analysis identified surgery prior to Gamma Knife surgery as an unfavorable factor of symptom change.

Conclusion

Gamma Knife radiosurgery provided long-term effective tumor control and better symptom recovery compared with those with prior surgery. Patients with surgery before Gamma Knife radiosurgery were more likely to have stable symptoms. Further analyses indicated that long follow-up is essential to determine the efficacy of radiosurgery for parasellar meningiomas. Further study needs to include more patients with longer follow-up to draw a more solid conclusion.

Multisession radiosurgery for intracranial meningioma treatment: study protocol of a single arm, monocenter, prospective trial

Background

Single session radiosurgery represents a widely accepted treatment for intracranial meningiomas. However, this approach could involve a high risk of treatment-related complications when applied to large volume lesions. In these cases and for those not suitable for surgical resection, radiosurgery in multisession setting could represents a viable option. The literature results are reassuring in terms of correlated adverse events as well as in terms of tumor control. However, no prospective long-term results are available. In this scenario, we design a prospective monocentric phase II study, in order to verify the safety of a multisession radiosurgery schedule delivering 25 Gy in 5 daily fractions.

Methods

Patients diagnosed with large and/or near to critical structures, intracranial meningiomas have been treated by means of multisession radiosurgery in both exclusive and postoperative settings. The primary study aim is safety that has been being prospectively scored based on international scales, including NCI Common Toxicity criteria, version 4.03, Barrow Neurological Institute pain intensity score, Barrow Neurological Institute facial numbness score and House-Brackmann Facial Nerve Grading System for qualitative analysis. Secondary aim is treatment efficacy in terms of local control that has been being assessed on volumetric analysis.

Discussion

This is the first prospective phase II trial on multisession radiosurgery for large and/or near to critical structures intracranial meningiomas. If positive results will be found, this study could represent the starting point for a phase III trial exploring the role of multisession radiosurgery in the exclusive and postoperative radiation therapy treatment of intracranial meningiomas.

Trial registration

Trial registration: clinicaltrials.gov platform (Multisession Radiosurgery in Large Meningiomas –MuRaLM- identifier NCT02974127). Registered: November 28, 2016. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02974127?term=radiosurgery&cond=Intracranial+Meningioma&draw=2&rank=1

Radiotherapy of Parasellar Tumours

Parasellar tumours represent a wide group of intracranial lesions, both benign and malignant. They may arise from several structures located within the parasellar area or they may infiltrate or metastasize this region. The treatment of the tumours located in these areas is challenging because of their complex anatomical location and their heterogenous histology. It often requires a multimodal approach, including surgery, radiation therapy (RT), and medical therapy. Due to the proximity of critical structures and the risks of side effects related to the procedure, a successful surgical resection is often not achievable. Thus, RT plays a crucial role in the treatment of several parasellar tumours. Conventional fractionated RT and modern radiation techniques, like stereotactic radiosurgery and proton beam RT, have become a standard management option, in particular for cases with residual or recurrent tumours after surgery and for those cases where surgery is contraindicated. This review examines the role of RT in parasellar tumours analysing several techniques, outcomes and side effects.

Parasellar Meningiomas

Parasellar spaces remain particularly singular, comprising the most important neurovascular structures such as the internal carotid artery and optic, oculomotor, and trigeminal nerves. Meningiomas are one of the most frequent tumors arising from parasellar spaces. In this location, meningiomas remain mostly benign tumors with WHO grade I and a meningothelial subtype. Progestin intake should be investigated and leads mostly to conservative strategies. In the case of benign nonsymptomatic tumors, observation should be proposed. Tumor growth will lead to the proposition of surgery or radiosurgery. In the case of an uncertain diagnosis and an aggressive pattern, a precise diagnosis is required. For cavernous sinus and Meckel's cave lesions, complete removal is rarely considered, leading to the proposition of an endoscopic endonasal or transcranial biopsy. Optic nerve decompression could also be proposed via these approaches. A case-by-case discussion about the best approach is recommended. A transcranial approach remains necessary for tumor removal in most cases. Vascular injury could lead to severe complications. Cerebrospinal fluid leakage, meningitis, venous sacrifice, visual impairment, and cranial nerve palsies are more frequent complications. Pituitary dysfunctions are rare in preoperative assessment and in postoperative follow-up but should be assessed in the case of meningiomas located close to the pituitary axis. Long-term follow-up is required given the frequent incomplete tumor removal and the risk of delayed recurrence. Radiosurgery is relevant for small and well-limited meningiomas or intra-cavernous sinus postoperative residue, whereas radiation therapy and proton beam therapy are indicated for large, extended, nonoperable meningiomas. The place of the peptide receptor radionuclide therapyneeds to be defined. Targeted therapy should be considered in rare, recurrent, and aggressive parasellar meningiomas.

Benign Intracranial Lesions - Radiotherapy: An Overview of Treatment Options, Indications and Therapeutic Results

BACKGROUND

Radiation Therapy (RT) is an established treatment option for benign intracranial lesions. The aim of this study is to display an update on the role of RT concerning the most frequent benign brain lesions and tumors.

METHODS

Published articles about RT and meningiomas, Vestibular Schwannomas (VSs), Pituitary Adenomas (PAs), Arteriovenous Malformations (AVMs) and craniopharyngiomas were reviewed and extracted data were used.

RESULTS

In meningiomas RT is applied as an adjuvant therapy, in case of patientrefusing surgery or in unresectable tumors. The available techniques are External Beam RT (EBRT) and stereotactic ones such as Stereotactic Radiosurgery (SRS), Fractionated Stereotactic RT (FSRT), Intensity Modulated RT (IMRT) and proton-beam therapy. The same indications are considered in PAs, in which SRS and FSRT achieve excellent tumor control rate (92-100%), acceptable hormone remission rates (>50%) and decreased Adverse Radiation Effects (AREs). Upon tumor growth or neurological deterioration, RT emerges as alone or adjuvant treatment against VSs, with SRS, FSRT, EBRT or protonbeam therapy presenting excellent tumor control growth (>90%), facial nerve (84-100%), trigeminal nerve (74-99%) and hearing (>50%) preservation. SRS poses an effective treatment modality of certain AVMs, demonstrating a 3-year obliteration rate of 80%. Lastly, a combination of microsurgery and RT presents equal local control and 5-year survival rate (>90%) but improved toxicity profile compared to total resection in case of craniopharyngiomas.

CONCLUSION

RT comprises an effective treatment modality of benign brain and intracranial lesions. By minimizing its AREs with optimal use, RT projects as a potent tool against such diseases.

Risk of internal carotid artery stenosis or occlusion after single-fraction radiosurgery for benign parasellar tumors

OBJECTIVE

Stereotactic radiosurgery (SRS) is an accepted treatment option for patients with benign parasellar tumors. Here, the authors' objective was to determine the risk of developing new or progressive internal carotid artery (ICA) stenosis or occlusion after single-fraction SRS for cavernous sinus meningioma (CSM) or growth hormone-secreting pituitary adenoma (GHPA).

METHODS

The authors queried their prospectively maintained registry for patients treated with single-fraction SRS for CSM or GHPA in the period from 1990 to 2015. Study criteria included no prior irradiation and ≥ 12 months of post-SRS radiological follow-up. Pre-SRS grading of ICA involvement was applied according to the 1993 classification schemes of Hirsch for CSM or Knosp for GHPA.

RESULTS

The authors conducted a retrospective review of 283 patients, 155 with CSMs and 128 with GHPAs. Ninety-three (60%) CSMs were Hirsch category 2 and 3 tumors; 97 (76%) GHPAs were Knosp grade 2-4 tumors. Median follow-up after SRS was 6.6 years (IQR 1-24.9 years). No GHPA or category 1 CSM developed ICA stenosis or occlusion. Three (5.2%) patients with category 2 CSMs had asymptomatic ICA stenosis (n = 2) or occlusion (n = 1); 1 (1.1%) category 2 CSM patient had transient ischemic symptoms. Five (14.3%) category 3 CSMs progressed to ICA occlusion (4 asymptomatic, 1 symptomatic). The median time to stenosis/occlusion was 4.8 years (IQR 1.8-7.6). Five- and 10-year risks of ICA stenosis/occlusion in category 2 and 3 CSM patients were 7.5% and 12.4%, respectively. Five- and 10-year risks of ischemic stroke from ICA stenosis/occlusion in category 2 and 3 CSM patients were both 1.2%. Multivariate analysis showed patient age (HR 0.92, 95% CI 0.86-0.98, p = 0.01), meningioma pathology (HR and 95% CI not defined, p = 0.03), and pre-SRS carotid category (HR 4.51, 95% CI 1.77-14.61, p = 0.004) to be associated with ICA stenosis/occlusion. Internal carotid artery stenosis/occlusion was not related to post-SRS tumor growth (HR and 95% CI not defined, p = 0.41).

CONCLUSIONS

New or progressive ICA stenosis/occlusion was common after SRS for CSM but was not observed after SRS for GHPA, suggesting a tumor-specific mechanism unrelated to radiation dose. Pre-SRS ICA encasement or constriction increases the risk of ICA stenosis/occlusion; however, the risk of ischemic complications is very low.

Stereotactic Radiosurgery of Cavernous Sinus Meningiomas

Objective  Microsurgical resection of cavernous sinus meningiomas (CSM) is associated with a high rate of incomplete resection, recurrence, and the risk for permanent, severe cranial nerve deficits. Stereotactic radiosurgery (SRS) has evolved as alternative treatment for primary and recurrent CSM. Here, we report about the long-term clinical and radiological follow-up (FU) of a unique cohort of patients with CSM treated with LINAC or Cyberknife based SRS. Methods  In this single-center retrospective analysis, we include all patients with CSM who underwent single fraction SRS between 1993 and 2016. Clinical and radiological tumor control were evaluated by the Kaplan-Meier method. Additionally, patient data were analyzed in terms of symptom control and incidence of side effects rated by the common terminology criteria for adverse events (CTCAE; v4.03). Results  116 patients (female/male = 91/25; median age, 54 years; range, 33-82 years) were included. Mean tumor volume was 5.7 ± 3.3 cm ³ (range, 0.6-16.2 cm ³ ), the median marginal dose was 12.6 Gy applied to isodose levels of 75%. Median clinical FU was 55 months (range, 3-226 months). Tumor control was 98% after 2 and 5 years and 90% after 10 years. Twelve patients (10.3%) had permanent or transient radiation related toxicity (CTCAE I-III). An improvement of symptoms was observed in 26.7% of the symptomatic patients ( n  = 20 of 75). Conclusion  SRS for CSM provides excellent long-term tumor and symptom control without considerable permanent side effects. Thus, SRS should be considered when counseling patients suffering from CSM.

Stereotactic radiosurgery for hypervascular intracranial tumors

OBJECTIVE

To evaluate the safety and efficacy of SRS treatment of central neurocytomas (CNCs), cavernous sinus hemangiomas (CSHs), and glomus tumors (GTs); and to compare upfront stereotactic radiosurgery (SRS) and adjuvant SRS in the treatment of these hypervascular tumors.

METHODS

This was a retrospective review of consecutive CNCs, CSHs, and GTs treated with SRS between 1993 and 2017. Tumor response was categorized based on volumetric analysis on magnetic resonance imaging: (1) tumor regression [> 10% decrease in tumor volume (TV)]; (2) stable tumor (≤ 10% change in TV); or (3) tumor progression (> 10% increase in TV).

RESULTS

Sixty hypervascular tumors (CNC: 28; CSH: 16; GT: 16) underwent SRS between 1993 and 2017. Margin doses were 13 Gy, 12 Gy, and 14 Gy for CNCs, CSHs, and GTs, respectively. Tumor regression was observed in 54 tumors (90%) with initial SRS after a median follow-up of 82 months. Relative reductions in TVs for CNCs were 38%, 52%, and 73% at 12, 24, and 48 months, respectively. Relative reductions in TVs for CSHs were 51%, 68%, and 88% at 12, 24, and 48 months, respectively. Relative reductions in TVs for GTs were 22%, 31%, and 47% at 12, 24, and 48 months, respectively. Upfront SRS was performed in 26 patients (43%). No difference in relative TV reductions were found between upfront and adjuvant SRS. Adverse radiation effects were observed in five patients. No mortality was encountered.

CONCLUSION

SRS for hypervascular tumors is associated with high rates of tumor regression with low risk of complications. No significant difference in rates of relative TV reduction were found between upfront and adjuvant SRS. Hence, upfront SRS may be considered in select patients.