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Introduction: Radiation therapy is often used to treat meningioma with adverse features or when unresectable. Proton therapy has advantages over photon therapy in reducing integral dose to the brain. This study compared the incidence of radiological and clinical adverse events after photon versus proton therapy in the treatment of meningioma., Methods: A retrospective review was conducted on patients with meningioma treated with proton or photon therapy at two high-volume tertiary cancer centers. Patients with a history of prior radiation therapy (RT) or less than 3 months of follow-up were excluded. Post-RT imaging changes were categorized into abnormal T2 signal intensities (T2 changes) or abnormal T1 post-contrast and T2 signal intensities (T1c+T2 changes) on magnetic resonance imaging (MRI). Clinical outcomes of adverse events and survival were compared between the proton and photon therapies., Results: Among the total of 77 patients, 38 patients received proton therapy and 39 patients received photon therapy. The median age at diagnosis was 55 years and median follow-up was 2.2 years. No significant differences in symptomatic adverse events were observed between the two groups: grade ≥ 2 adverse events were seen in 4 (10.5%) patients in the proton group and 3 (7.7%) patients in the photon group (p = 0.67). The 2-year cumulative incidences of T2 changes were 38.3% after proton therapy and 47.7% after photon therapy (p = 0.53) and the 2-year cumulative incidences of T1c+T2 changes were 26.8% after proton therapy and 5.3% after photon therapy (p = 0.02). One patient experienced grade ≥ 4 adverse event in each group (p = 0.99). Estimated 2-year progression-free survival was 79.5% (proton therapy 76.0% vs. photon therapy 81.3%, p = 0.66) and 2-year overall survival was 89.7% (proton therapy 86.6% vs. photon therapy 89.3%, p = 0.65)., Conclusions: Following RT, high rates of T2 changes were seen in meningioma patients regardless of treatment modality. Proton therapy was associated with significantly higher rates of T1c+T2 changes compared with photon therapy, but severe adverse events were uncommon in both groups and survival outcomes were comparable between the two groups. Future studies will aim at correlating the MRI changes with models that can be incorporated into RT planning to avoid toxicity.

Background: Rhabdoid meningiomas are rare World Health Organization grade 3 tumors that tend to follow an aggressive course, with an increased likelihood for local recurrence, remote metastasis, and cerebrospinal fluid dissemination. Genetic testing has found certain genes associated with reduced time to tumor recurrence. BAP1 (BRCA1-associated protein 1) is a tumor suppressor gene that is associated with multiple tumors, including rhabdoid meningiomas., Case Description: We present a case of a pediatric patient who presented with a rhabdoid meningioma occurring in the right tentorium and invading multiple venous structures, including the right jugular vein. The patient underwent 5 separate operations for management of this tumor. The first surgery was an intracranial tumor debulking with reconstruction of venous structures. Postoperatively, the patient was unable to have the ventricular catheter removed and underwent placement of a ventriculoperitoneal shunt. Significant recurrence of the intracranial portion of tumor was found during preoperative imaging for her second stage procedure. She underwent a second craniotomy for resection of the tumor. Her postoperative magnetic resonance imaging showed significant residual tumor and the patient therefore underwent a third craniotomy for total tumor resection, which involved reconstruction of the superior sagittal sinus. She did well after this surgery, with no new neurologic deficits. Her final operation involved resection of the residual tumor in the neck and chest by both otolaryngology and cardiothoracic surgery. This surgery involved opening the jugular vein and resecting residual tumor from the intima. Pathologic results from all surgeries were consistent with rhabdoid meningioma; however, the tissue from the biopsy and first craniotomy lacked the high-grade features that were found on subsequent resections. Genetic analysis found loss of both BAP1 tumor suppressor genes. Peripheral blood testing showed that this patient was a germline carrier of a pathogenic BAP1 variant., Discussion: Pediatric rhabdoid meningiomas represent a rare disease and are found on recurrent tumors in conjunction with lower-grade meningioma disease. Our patient presented with what was initially believed to be a low-grade meningioma with rhabdoid features, which then transformed into a World Health Organization grade III rhabdoid meningioma on recurrence. This tumor was discovered to have a biallelic loss of BAP-1 mutation and the patient was found to have a germline mutation in 1 of her BAP-1 alleles. Germline mutations in BAP-1 are associated with a cancer syndrome that involves uveal and cutaneous melanoma, malignant mesothelioma, atypical Spitz tumors, and clear-cell renal cell carcinoma. Patients with this mutation are encouraged to undergo annual eye examinations starting at the age of 11 years. The BAP-1 tumor predisposition syndrome is most commonly an inherited mutation associated with incomplete penetrance and variation with nonoverlapping tumor types., Conclusions: Rhabdoid meningiomas are unlikely to be found in children and have a high rate of local recurrence. Gross total resection has to be balanced with risk of postoperative deficit. Genetic testing of this rare entity should be performed to identify any hereditary germline mutations., (Published by Elsevier Inc.)

Maximal safe resection has long been the cornerstone of treatment for WHO grade I benign meningioma. However, as technology for both imaging and radiation delivery has advanced, radiation therapy has played an increasingly important role in the management of patients with WHO grade I meningioma. Radiation therapy, whether delivered as standard fractionated treatment over several weeks, stereotactic radiosurgery over 1 session, or multisession stereotactic radiation therapy, has been shown to provide excellent local control when used as an adjunct to surgery or as primary treatment. Here, we review the indications for radiation therapy for patients with WHO grade I meningioma, as well as the various techniques that have been developed. We also review the toxicities and late effects associated with treatment.

Purpose: Given the excellent prognosis for patients with benign meningiomas, treatment strategies to minimize late effects are important. One strategy is proton radiation therapy (RT), which allows less integral dose to normal tissue and greater homogeneity than photon RT. Here, we report the first series of proton stereotactic radiosurgery (SRS) used for the treatment of meningiomas., Methods and Materials: We identified 50 patients with 51 histologically proven or image-defined, presumed-benign meningiomas treated at our institution between 1996 and 2007. Tumors of <4 cm in diameter and located≥2 mm from the optic apparatus were eligible for treatment. Indications included primary treatment (n=32), residual tumor following surgery (n=8), and recurrent tumor following surgery (n=10). The median dose delivered was 13 Gray radiobiologic equivalent (Gy[RBE]) (range, 10.0-15.5 Gy[RBE]) prescribed to the 90% isodose line., Results: Median follow-up was 32 months (range, 6-133 months). Magnetic resonance imaging at the most recent follow-up or time of progression revealed 33 meningiomas with stable sizes, 13 meningiomas with decreased size, and 5 meningiomas with increased size. The 3-year actuarial tumor control rate was 94% (95% confidence interval, 77%-98%). Symptoms were improved in 47% (16/34) of patients, unchanged in 44% (15/34) of patients, and worse in 9% (3/34) of patients. The rate of potential permanent adverse effects after SRS was 5.9% (3/51 patients)., Conclusions: Proton SRS is an effective therapy for small benign meningiomas, with a potentially lower rate of long-term treatment-related morbidity. Longer follow-up is needed to assess durability of tumor control and late effects., (Copyright © 2011 Elsevier Inc. All rights reserved.)