Dataset Information

NCOG-52. TUMOR TREATING FIELDS IN MENINGIOMA

ABSTRACT: Abstract

BACKGROUND

High-grade meningioma are aggressive intracranial tumors and currently only limited treatment options exist. Therefore, there is a need for further studies in search of new therapies. Tumor Treating TTFields (TTFields) therapy serves as an effective treatment against glioblastoma (GBM). Phase 3 clinical trials investigate the use of TTFields in other intracranial tumors, i.e. brain metastases of the non-small cell lung cancer. We here provide an overview of the currently available data regarding the use of TTFields in meningioma.

MATERIALS AND METHODS

We performed a literature search using the term “Tumor treating fields” “NovoTTF”, “TTFields” and “Optune” in combination with “Meningioma”. A brief overview of TTFields in meningioma is provided here.

RESULTS

In vitro studies using patient-derived anaplastic grade III meningioma cell lines showed that TTFields treatment at a frequency of 200 kHz causes a significant reduction of cell proliferation and clonogenicity as well as altering cell morphology. In a case report of a 44-year-old woman suffering from a right anterior temporal tumor as well as a distant right parietal extra-axial convexity meningioma TTFields and Temozolomide treatment was initiated. Brain MRI scans 8, 16 and 20 weeks later showed a reduction in the meningioma tumor size of 42%, 58% & 60%, respectively. Currently, two ongoing trials test the efficacy and safety of the use of TTFields in meningioma patients: a phase II single arm trial (n=27), investigating the combination of TTFields and Bevacizumab in recurrent or progressive meningioma (NCT02847559); and a pilot trial, investigating the effects of TTFields as monotherapy on recurrent atypical and anaplastic meningioma (NCT01892397).

CONCLUSIONS

First data indicate that TTFields might be an option in future high-grade meningioma treatment. Clinical trials need to show safety and efficacy for the TTFields treatment in meningioma patients.

SUBMITTER: Mawrin C

PROVIDER: S-EPMC7651609 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Glioblastoma is the most common yet most lethal of primary brain cancers with a one-year post-diagnosis survival rate of 65% and a five-year survival rate of barely 5%. Recently the U.S. Food and Drug Administration approved a novel fourth approach (in addition to surgery, radiation therapy, and chemotherapy) to treating glioblastoma; namely, tumor treating fields (TTFields). TTFields involves the delivery of alternating electric fields to the tumor but its mechanisms of action are not fully understood. Current theories involve TTFields disrupting mitosis due to interference with proper mitotic spindle assembly. We show that TTFields also alters cellular membrane structure thus rendering it more permeant to chemotherapeutics. Increased membrane permeability through the imposition of TTFields was shown by several approaches. For example, increased permeability was indicated through increased bioluminescence with TTFields exposure or with the increased binding and ingress of membrane-associating reagents such as Dextran-FITC or ethidium D or with the demonstration by scanning electron microscopy of augmented number and sizes of holes on the cellular membrane. Further investigations showed that increases in bioluminescence and membrane hole production with TTFields exposure disappeared by 24?h after cessation of alternating electric fields thus demonstrating that this phenomenom is reversible. Preliminary investigations showed that TTFields did not induce membrane holes in normal human fibroblasts thus suggesting that the phenomenom was specific to cancer cells. With TTFields, we present evidence showing augmented membrane accessibility by compounds such as 5-aminolevulinic acid, a reagent used intraoperatively to delineate tumor from normal tissue in glioblastoma patients. In addition, this mechanism helps to explain previous reports of additive and synergistic effects between TTFields and other chemotherapies. These findings have implications for the design of combination therapies in glioblastoma and other cancers and may significantly alter standard of care strategies for these diseases.

Project description:PurposeSince the inception of tumor treating fields (TTFields) therapy as a Food and Drug Administration-approved treatment with known clinical efficacy against recurrent and newly diagnosed glioblastoma, various in silico modeling studies have been performed in an effort to better understand the distribution of applied electric fields throughout the human body for various malignancies or metastases.Methods and materialsPostacquisition attenuation-corrected positron emission tomography-computed tomography image data sets from 2 patients with ovarian carcinoma were used to fully segment various intrapelvic and intra-abdominal gross anatomic structures. A 3-dimensional finite element mesh model was generated and then solved for the distribution of applied electric fields, rate of energy deposition, and current density at the clinical target volumes (CTVs) and other intrapelvic and intra-abdominal structures. Electric field-volume histograms, specific absorption rate-volume histograms, and current density-volume histograms were generated, by which plan quality metrics were derived from and used to evaluate relative differences in field coverage between models under various conditions.ResultsTTFields therapy distribution throughout the pelvis and abdomen was largely heterogeneous, where specifically the field intensity at the CTV was heavily influenced by surrounding anatomic structures as well as its shape and location. The electric conductivity of the CTV had a direct effect on the field strength within itself, as did the position of the arrays on the surface of the pelvis and/or abdomen.ConclusionThe combined use of electric field-volume histograms, specific absorption rate-volume histograms, current density-volume histograms, and plan quality metrics enables a personalized method to dosimetrically evaluate patients receiving TTFields therapy for ovarian carcinoma when certain patient- and tumor-specific factors are integrated with the treatment plan.