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.

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.

Therapeutic Approaches in Adult Primary Spinal Cord Astrocytoma: A Systematic Review.

THE ISSUE: Gliomas are primary tumors arising from supporting cells of the central nervous system (CNS), usually in the brain. The 2021 World Health Organization (WHO) classifies gliomas as adult-type diffuse gliomas or circumscribed astrocytic gliomas depending on their histology and molecular features. Spinal astrocytic gliomas are very rare, and nowadays no standard of therapy is available. Treatment options are limited: surgery is often not radical, and adjuvant therapies include mostly radiotherapy (RT) or systemic chemotherapy (CHT). There is lack of knowledge about the efficacy and safety of therapies and their multidisciplinary approaches. THE AIM OF THE REVIEW: A systematic review of the literature from January 2000 to June 2021 was performed, including both clinical trials and observational studies on histological adult primary spinal cord astrocytomas (SCA), with a minimum follow-up of 6 months and reporting the overall survival, progression-free survival or clinical neurological outcome after any therapeutic approach (surgery, RT or CHT). What are the main findings? A total of 1197 citations were identified by the Medline search and additional records; based on our inclusion criteria, 18 studies were included with a total of 285 adult patients. We documented the lack of any clinical trial. What are the conclusions? The available literature data are limited to series/retrospective studies, including heterogeneous patients, i.e., astrocytoma as well as ependymoma or pediatric/adult age, with scanty data on the outcomes of interest. No clinical trials have been run. Due to the rarity of this disease, multicentric clinical trials with molecular investigations are mandatory to better manage such a rare disease.

On the evaluation of edgeless diode detectors for patient-specific QA in high-dose stereotactic radiosurgery.

PURPOSE: In this work, the potential of an innovative "edgeless" silicon diode was evaluated as a response to the still unmet need of a reliable tool for plan dosimetry verification of very high dose, non-coplanar, patient-specific radiosurgery treatments. In order to prove the effectiveness of the proposed technology, we focused on radiosurgical treatments for functional disease like tremor or pain. METHODS: The edgeless diodes response has been validated with respect to clinical practice standard detectors by reproducing the reference dosimetry data adopted for the Treatment Planning System. In order to evaluate the potential for radiosurgery patient-specific treatment plan verification, the anthropomorphic phantom Alderson RANDO has been adopted along with three edgeless sensors, one placed in the centre of the Planning Target Volume, one superiorly and one inferiorly. RESULTS: The reference dosimetry data obtained from the edgeless detectors are within 2.6% for output factor, off-axis ratio and well within 2% for tissue phantom ratio when compared to PTW 60,018 diode. The edgeless detectors measure a dose discrepancy of approximately 3.6% from the mean value calculated by the TPS. Larger discrepancies are obtained in very steep gradient dose regions when the sensors are placed outside the PTV. CONCLUSIONS: The angular independent edgeless diode is proposed as an innovative dosimeter for patient quality assurance of brain functional disorders and other radiosurgery treatments. The comparison of the diode measurements with TPS calculations confirms that edgeless diodes are suitable candidates for patient-specific dosimetric verification in very high dose ranges delivered by non-isocentric stereotactic radiosurgery modalities.

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.

Skull-base surgery during the COVID-19 pandemic: the Italian Skull Base Society recommendations.

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is highly contagious with devastating impacts for healthcare systems worldwide. Medical staff are at high risk of viral contamination and it is imperative to know what personal protective equipment (PPE) is appropriate for each situation. Furthermore, elective clinics and operations have been reduced in order to mobilize manpower to the acute specialties combating the outbreak; appropriate differentiation between patients who require immediate care and those who can receive telephone consultation or whose treatment might viably be postponed is therefore crucial. Italy was 1 of the earliest and hardest-hit European countries and therefore the Italian Skull Base Society board has promulgated specific recommendations based on consensus best practices and the literature, where available. Only urgent surgical operations are recommended and all patients should be tested at least twice (on days 4 and 2 prior to surgery). For positive patients, procedures should be postponed until after swab test negativization. If the procedure is vital to the survival of the patient, filtering facepiece 3 (FFP3) and/or powered air purifying respirator (PAPR) devices, goggles, full-face visor, double gloves, water-resistant gowns, and protective caps are mandatory. For negative patients, use of at least an FFP2 mask is recommended. In all cases the use of drills, which promote the aerosolization of potentially infected mucous particles, should be avoided. Given the potential neurotropism of SARS-CoV-2, dura handling should be minimized. It is only through widely-agreed protocols and teamwork that we will be able to deal with the evolving and complex implications of this new pandemic.

Multisession radiosurgery for perioptic meningiomas: medium-to-long term results from a CyberKnife cooperative study.

PURPOSE: Most recent literature has confirmed the efficacy of single-session radiosurgery (sRS) in the treatment of intracranial meningioma. Unfortunately, sRS is not always applicable due to large tumor volume and the proximity of the tumor to critical structures. When sRS is not recommended, multi-session radiosurgery (mRS) can be the solution. The best treatment schedule for mRS, however, is not well established. The aim of the present retrospective study is to validate the effectiveness of one approach, 25 Gy delivered in 5 fractions in 5 consecutive days, to treat skull base meningiomas. METHODS: This is a retrospective multicenter study. Patients with an anterior or a medium skull base meningioma that could not be treated by sRS due to large volume or proximity to the anterior optic pathways (AOPs) underwent 5-fraction mRS. Only patients with at least 36 months follow-up were included in the analysis. Local control and visual outcomes were investigated. RESULTS: One-hundred-sixty-seven patients were included in the analysis. One-hundred-one patients underwent RS as a primary indication and 66 were treated after a previous surgery. The median follow-up period was 51 months (range 36-129 months). Progression-free survival at 3, 5 and 8 years were, respectively, 98%, 94% and 90%. Excluding the progressive disease patients, the visual worsening rate was 3.7%. The 42% of the patients with a pre-treatment visual deficit experienced improvement in vision. CONCLUSION: 25 Gy delivered in 5 fractions is an effective modality for meningiomas that are near the AOP or are too large to be treated by sRS. The treatment schedule controlled the tumors while sparing visual function.

Radiosurgery for trigeminal neuralgia: the state of art.

The trigeminal neuralgia (TN) is a chronic, episodic, and disabling facial pain syndrome. It is a relatively rare disorder. Despite this, because of the intensity of the pain, TN may have a dramatic impact for many patients. Fortunately, most of the patients may obtain a good pain relief simply by taking drugs. Historically, the surgical approaches represent a true treatment paradigm for all the drug-resistant TN. In this context, radiosurgery (RS) is a relatively new treatment modality. The effectiveness and safety of radiosurgery are today widely accepted and the technique can be proposed to many patients which suffer from a drug-resistant TN. This is true especially when the patients are less than ideal candidates for an open surgery, or for elderly ones, when a clear neuro-vascular conflict is not evident. The present review provides a concise analysis of the actual indications for radiosurgery, as well as the most acknowledged prognostic factors. The pathogenesis of TN and the rationale for the RS efficacy are also investigated and described. Some technical aspects including the target selection and the prescription doses, which have widely changed in time, are depicted. In conclusion, the present review supports the idea that TN is a complex disease and radiosurgery represents an effective and relatively new treatment modality, which enriches the treatment armamentarium for these unfortunate patients. To optimize the RS results, a correct patient selection has to be performed.

Integration of Functional Magnetic Resonance Imaging and Magnetoencephalography Functional Maps Into a CyberKnife Planning System: Feasibility Study for Motor Activity Localization and Dose Planning.

OBJECTIVE: Magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) provide noninvasive localization of eloquent brain areas for presurgical planning. The aim of this study is the integration of MEG and fMRI maps into a CyberKnife (CK) system to optimize dose planning. METHODS: Four patients with brain metastases in the motor area underwent functional imaging study of the hand motor cortex before radiosurgery. MEG data were acquired during a visually cued hand motor task. Motor activations were identified also using an fMRI block-designed paradigm. MEG and fMRI maps were then integrated into a CK system and contoured as organs at risk for treatment planning optimization. RESULTS: The integration of fMRI data into the CK system was achieved for all patients by means of a standardized protocol. We also implemented an ad hoc pipeline to convert the MEG signal into a DICOM standard, to make sure that it was readable by our CK treatment planning system. Inclusion of the activation areas into the optimization plan allowed the creation of treatment plans that reduced the irradiation of the motor cortex yet not affecting the brain peripheral dose. CONCLUSIONS: The availability of advanced neuroimaging techniques is playing an increasingly important role in radiosurgical planning strategy. We successfully imported MEG and fMRI activations into a CK system. This additional information can improve dose sparing of eloquent areas, allowing a more comprehensive investigation of the related dose-volume constraints that in theory could translate into a gain in tumor local control, and a reduction of neurological complications.

Differentiating brain radionecrosis from tumour recurrence: a role for contrast-enhanced ultrasound?

Differentiating radionecrosis from tumour recurrence is a major issue in neuro-oncology. Conventional imaging is far from being validated as an alternative to histological assessment. We report the case of a patient operated on for suspected recurrence of brain metastasis 9 months after cyberknife radiosurgery. While magnetic resonance imaging showed strong enhancement of the lesion, intraoperative contrast-enhanced ultrasonography (CEUS) surprisingly did not-different from what is expected for brain metastases. Histopathological examination documented radionecrosis. For the first time, we describe radionecrosis with CEUS; further investigation is needed; however, the lack of enhancement could represent an important hallmark in differential diagnosis with neoplastic tissue.

Short course radiotherapy concomitant with temozolomide in GBM patients: a phase II study.

PURPOSE: Despite recent advances, the prognosis of glioblastoma (GBM) remains poor. The aim of this study was to assess the efficacy and tolerability of multiple daily fraction radiotherapy performed with multiple temozolomide (TMZ) administrations in newly diagnosed patients with GBM. METHODS: This trial was a prospective, open-label, monocentric, nonrandomized, single arm, phase II study. The primary endpoint was the proportion of progression-free patients at 12 months, and the secondary endpoints were overall survival (OS) and toxicity. Thirty-five patients underwent two radiotherapy courses concomitant with TMZ after surgery. At each course, radiation was delivered 3 times daily, 2 Gy/fraction, for 5 consecutive days, and the total dose was 60 Gy; concurrent TMZ was administered in a total dose of 150-200 mg/m2/day. RESULTS: The primary endpoint failed to be applied; Macdonald criteria could be used in 16 (46%) patients with local or intracerebral recurrence (group A). In 12 patients, due to suspicion of radiation necrosis vs recurrence, Macdonald criteria were not applied (group B). The OS was 22 months, and OS probabilities at 12, 18, and 24 months were 82%, 59%, and 44%, respectively. Hematologic toxicities generally did not exceed grade 2. The quality of life and cognitive functioning did not significantly change between baseline and the first follow-up. In the multivariate analysis, necrosis and pseudoprogression were significant prognostic factors of OS. CONCLUSIONS: To improve local control and OS, a more aggressive treatment schedule should be explored. The related higher necrosis risk and its implications regarding local control deserve further investigation.

Treatments of glossopharyngeal neuralgia: towards standard procedures.

The degree of disability due to glossopharyngeal neuralgia (GN) refractory to conservative treatments justifies surgical procedures as second-line treatments. Since the first description of this facial pain disorders, many surgical options have been described either via a percutaneous or an open surgical way. Actually, when a neurovascular conflict on root entry zone (REZ) or cisternal portion of the ninth and tenth cranial nerves is identified, microvascular decompression (MVD) is the first surgical option to consider. Many studies have demonstrated its efficacy and safety for the treatment of GN. Recently, stereotactic radiosurgery has gained space in the treatment of selected cases of GN. We provide an overview of the surgical procedures for the treatment of GN and of our own experience.

The role of radiosurgery in trigeminal neuralgia.

A short review of clinical use of radiosurgery in trigeminal neuralgia is offered.

Radiosurgery for Paragangliomas of the Head and Neck: Another Step for the Validation of a Treatment Paradigm.

BACKGROUND: Paragangliomas are highly vascular and predominantly benign neoplasms that traditionally have been treated by surgery, embolization, and/or external beam radiotherapy. The aim of this study was to evaluate long-term local tumor control and the safety of radiosurgery for head and neck paragangliomas. METHODS: Data were obtained from prospectively maintained databases of patients affected by brain tumors treated with radiosurgery at our institution. The inclusion criteria were histologically proven or radiologic-suspected diagnosis of paragangliomas; a follow-up period of at least 12 months, an magnetic resonance imaging-based tumor growth control analysis and a signed written consent. Twenty patients (21 paragangliomas) met the eligibility criteria and were included in the present study. All patients were clinically and radiologically evaluated before and after treatment. RESULTS: The mean follow-up at the time of the present analysis was 46 months. Seven patients had a follow-up longer than 60 months. Seven lesions underwent a single-session radiosurgery with a mean dose of 12.2 Gy (range 11-13 Gy). Fourteen lesions underwent multisession radiosurgery with a mean dose of 25.7 Gy (range 20-30 Gy) delivered in 3-5 fractions. The mean tumor volume for single-session radiosurgery was 4 cc (range 1.4-9.2). The mean volume for multisession radiosurgery was 18.9 cc (range 1.3-50.9). None of the lesions showed progression on radiology during the follow-up period. Neurologic conditions generally are maintained or improved. CONCLUSIONS: Both single and multisession radiosurgery were confirmed as a safe and effective treatment modality for paragangliomas. Multisession radiosurgery appears effective to treat large lesions.

The cavernous sinus meningiomas' dilemma: Surgery or stereotactic radiosurgery?

Despite the advances in techniques and technologies, the management of cavernous sinus (CS) meningiomas still remains a challenge for both neurosurgeons and radiation oncologists. On the other hand, the improvement of the anatomical knowledge and the microsurgical techniques together with diffusion of radiosurgery are currently changing the treatment strategy, opening new perspectives to the patients which are suffering from such lesions. The authors reviewed here the literature data. A multidisciplinary treatment algorithm is also proposed.

Multisession Radiosurgery for Sellar and Parasellar Benign Meningiomas: Long-term Tumor Growth Control and Visual Outcome.

BACKGROUND: Concern about radiation-induced optic neuropathy (RION) has governed recent thinking about the role of radiation therapy in the treatment of meningiomas involving the anterior optic pathways. Despite this concern, during the last few years, the use of radiosurgery for such lesions has increased steadily. OBJECTIVE: To define both the tumor control rate and the risk of RION over a long-term follow-up period in a large cohort of patients treated with multisession radiosurgery. METHODS: The local control and visual outcome of 143 patients who underwent multisession radiosurgery (mRS) were evaluated. Neurological outcome was also analyzed. The data for the present study were obtained from a prospectively maintained database. RESULTS: The mean follow-up was 44 months (range, 12-113 months). All patients underwent mRS. The median prescription dose was 25 Gy delivered in 3 to 5 fractions. The prescription isodose, which typically encompassed at least 95% of the tumor, ranged from 65% to 86% (median, 80%). The mean tumor volume was 11.0 cm (range, 0.1-126.3 cm; median, 8 cm). The progression-free survival at 3, 5, and 8 years was 100%, 93%, and 90%, respectively. Compared with baseline, visual function improved in 36% of patients, whereas 7.4% experienced a worsening in visual function (5.1% excluding the patients with progressive disease). CONCLUSION: Good local control rate and a low risk of RION indicate that mRS is a safe and effective treatment option in cases of large meningiomas.

Radiosurgery reirradiation for high-grade glioma recurrence: a retrospective analysis.

Despite various treatment strategies being available, recurrent high-grade gliomas (r-HGG) are difficult to manage. To obtain local control, radiosurgery (SRS) reirradiation has been considered as potential treatment. In the present study, a retrospective analysis was performed on r-HGG patients treated with salvage single- (s-SRS) or multi-fraction SRS (m-SRS). The aim of this study was to evaluate the effectiveness of salvage SRS in terms of overall survival (OS); toxicity was analyzed as well. Between 2004 May and 2011 December, 128 r-HGG patients (161 lesions) treated with CyberKnife(®) SRS reirradiation were retrospectively analyzed. Toxicity was graded according to Radiation Therapy Oncology Group and by Common Terminology Criteria for Adverse Events v.3 criteria. OS from the diagnosis date and OS from reirradiation were estimated using the Kaplan-Meier method. Median follow-up was 9 months (range 15 days-82 months). All patients completed SRS without high-grade toxicity. Radiation necrosis was observed in seven patients (6 %) with large volume lesions. The median survival from initial diagnosis was 32 months. The 1-, 2-, and 3-years survival rates from diagnosis were 95, 62, and 45 % respectively. Median survival following SRS was 11.5 months. The 1-, 2-, and 3-years survival rate following SRS was 48, 20, and 17 % respectively. On multivariate analysis, age <40 years, salvage surgery before SRS, and other post-SRS therapies (second-line chemotherapy and/or surgery) were found to significantly improve survival (p = 0.03). SRS represents a safe and feasible option to treat r-HGG patients with low complication rates and potential survival benefit.

Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3.

Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses using this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk.