Although meningiomas are the most common intracranial tumours, the level of evidence to provide recommendations for the diagnosis and treatment of meningiomas is low compared with other tumours such as high-grade gliomas. The meningioma task force of the European Association of Neuro-Oncology (EANO) assessed the scientific literature and composed a framework of the best possible evidence-based recommendations for health professionals. The provisional diagnosis of meningioma is mainly made by MRI. Definitive diagnosis, including histological classification, grading, and molecular profiling, requires a surgical procedure to obtain tumour tissue. Therefore, in many elderly patients, observation is the best therapeutic option. If therapy is deemed necessary, the standard treatment is gross total surgical resection including the involved dura. As an alternative, radiosurgery can be done for small tumours, or fractionated radiotherapy in large or previously treated tumours. Treatment concepts combining surgery and radiosurgery or fractionated radiotherapy, which enable treatment of the complete tumour volume with low morbidity, are being developed. Pharmacotherapy for meningiomas has remained largely experimental. However, antiangiogenic drugs, peptide receptor radionuclide therapy, and targeted agents are promising candidates for future pharmacological approaches to treat refractory meningiomas across all WHO grades.

/pdf/eano-guidelines-for-the-diagnosis-and-treatment-of-5gu77627p6.pdf

EANO guidelines for the diagnosis and treatment of meningiomas

Evidence based assessment.

Secondary radiation emission induced by nuclear reactions is correlated to the path of ions in matter. Therefore, such penetrating radiation can be used for in vivo control of hadrontherapy treatments, for which the primary beam is absorbed inside the patient. Among secondary radiations, prompt-gamma rays were proposed for real-time verification of ion range. Such a verification is a desired condition to reduce uncertainties in treatment planning. For more than a decade, efforts have been undertaken worldwide to promote prompt-gamma-based devices to be used in clinical conditions. Dedicated cameras are necessary to overcome the challenges of a broad- and high-energy distribution, a large background, high instantaneous count rates, and compatibility constraints with patient irradiation. Several types of prompt-gamma imaging devices have been proposed, that are either physically-collimated or electronically collimated (Compton cameras). Clinical tests are now undergoing. Meanwhile, other methods than direct prompt-gamma imaging were proposed, that are based on specific counting using either time-of-flight or photon energy measurements. In the present article, we make a review and discuss the state of the art for all techniques using prompt-gamma detection to improve the quality assurance in hadrontherapy.

Prompt-gamma monitoring in hadrontherapy: A review

68Ga-DOTATATE PET/CT enables detection of meningioma tissue based on somatostatin receptor 2 expression. Transosseous extension of intracranial meningiomas is known to be an important risk factor for tumor recurrence and patient mortality. We analyzed the diagnostic performance of 68Ga-DOTATATE PET/CT and contrast-enhanced MRI (CE-MRI) for the detection of osseous infiltration using qualitative and quantitative imaging parameters. Methods: In this institutional review board-approved retrospective study, subjects were selected from 327 consecutive 68Ga-DOTATATE PET/CT examinations for evaluation of confirmed or suspected meningioma. Inclusion criteria were CE-MRI within 30 d and pathology-confirmed meningioma diagnosis with inclusion or exclusion of transosseous extension as the standard of reference. Imaging was analyzed by two readers. Tracer uptake values and meningioma volumes were determined. χ2, Mann-Whitney U, Wilcoxon signed rank, and McNemar tests, as well as receiver-operating-characteristic analyses, were performed to compare variables and diagnostic performance. Results: Eighty-two patients fulfilled the inclusion criteria. Patients with transosseous extension of meningioma (n = 67) showed significantly larger lesions (median, 12.8 vs. 3.3 mL; P < 0.001) and significantly higher tracer uptake values (median SUVmax, 14.2 vs. 7.6; P = 0.011) than patients with extraosseous meningiomas (n = 15). 68Ga-DOTATATE PET/CT in comparison to CE-MRI performed at a higher sensitivity (98.5% vs. 53.7%) while maintaining high specificity (86.7% vs. 93.3%) in the detection of osseous involvement (P < 0.001). In receiver-operating-characteristic analysis, PET/CT assessment performed better than CE-MRI (area under the curve, 0.932 vs. 0.773). PET/CT- and CE-MRI-based volume estimation yielded comparable results for extraosseous meningiomas (P = 0.132) and the extraosseous part of transosseous meningiomas (P = 0.636), whereas the volume of the intraosseous part was assessed as significantly larger by PET/CT (P < 0.001). Conclusion:68Ga-DOTATATE PET/CT enables improved detection of the transosseous extension of intracranial meningiomas compared with CE-MRI.

https://jnm.snmjournals.org/content/jnumed/58/10/1580.full.pdf

Improved Detection of Transosseous Meningiomas Using 68Ga-DOTATATE PET/CT Compared with Contrast-Enhanced MRI.

The differential diagnosis between meningioma and others tumors can be challenging. This study aimed to evaluate different immunohistochemical markers for the differential diagnosis between meningioma and their morphological mimics. Immunohistochemistry was performed on tissue microarray with antiepithelial membrane antigen (EMA), progesterone receptor, somatostatin receptor 2A (SSTR2A), CD34, STAT6, S100, SOX10, HMB45, MelanA, GFAP, inhibin, and BCL2 antibodies. One hundred and twenty-seven meningiomas, 26 solitary fibrous tumor/hemangiopericytomas (SFT/HPC), 39 schwannomas, 17 hemangioblastomas, 21 melanomas, 9 gliosarcomas, 5 neurofibromas, 9 peripheral primitive neuroectodermal tumors, 7 synovial sarcomas, and 5 malignant peripheral nerve sheath tumors were included in the microarray. SSTR2A was the most sensitive (95.2%) and specific (92%) marker of meningiomas. In combination, SSTR2A and/or EMA positivity reached maximal sensitivity (100%). Coexpression of SSTR2A and EMA was the most specific (94.8%) for the diagnosis of meningioma, regardless of the grade or subtype, with the exception of the differential diagnosis with synovial sarcoma. All synovial sarcomas were EMA-positive and 6/7 SSTR2A-positive. STAT6 showed optimum sensitivity and specificity (100%) for SFT/HPC. SOX10 was the most sensitive (94.3%) and specific (100%) marker to discriminate meningiomas from schwannomas. In conclusion, SSTR2A, STAT6, and SOX10 were the most sensitive and specific markers to distinguish meningiomas from their morphological mimics.

/pdf/immunohistochemical-approach-to-the-differential-diagnosis-5bosdfd1ks.pdf

Immunohistochemical Approach to the Differential Diagnosis of Meningiomas and Their Mimics.

The advantages of using C, He and O ions as therapeutical beam particles in Particle Therapy is related to their enhanced Relative Biological Effectiveness and Oxygen Enhancement Ratio, resulting in an improved efficacy in damaging the cancerous cells. However, an accurate on-line control of the dose release spatial distribution is required to spare the healthy tissues surrounding the tumor area, preventing undesired damages caused by, for example, morphological changes occurred in the patient during the treatment with respect to the initial CT scan. This monitor technology is currently missing in clinical practice, and several studies are being performed to develop beam range verification systems exploiting the detection of the emitted secondary radiation. Charged secondary particles, produced by the projectile fragmentation in the collisions with the patient tissues, represent an interesting chance for C, He and O treatments since they are also emitted at large angles with respect to the beam direction and can be detected with high efficiency in a nearly background free environment. The Dose Profiler detector is a scintillating fibre tracker that allows an online charged fragments reconstruction and backtracking. The construction and preliminary tests performed on the DP, carried out using the Carbon ions beam of the CNAO treatment centre using an anthropomorphic phantom as a target, will be reviewed in this contribution.

Elena Solfaroli Camillocci

Papers

In-room performance evaluation of a novel online charged secondary particles monitor of light ions PT treatments