Case report: durable response of gliomatosis cerebri with concurrent tumor-treating fields (TTFields) and chemoradiotherapy treatment

Background: Gliomatosis cerebri (GC) is a rare and aggressive form of widely disseminated glioma infiltrating at least 3 lobes of the brain. It is a diffuse pattern of growth of glioma rather than a distinct pathological diagnosed based on new Word Health Organization (WHO) classification. None the less, it is associated with worse prognosis to equally graded gliomas. Tumor treating fields (TTFields) treatment is a more recent advancement in glioma treatment through low energy, intermediate frequency (200 kHz) electromagnetic fields, with multi-modal mechanism of actions. It is Food and Drug Administration (FDA) approved for newly diagnosed and recurrent glioblastoma (GBM). The aim of the case report is to present durable response to GBM associated GC with concurrent TTFields with chemoradiation. Case Description: We report a 64-year-old male with left parietal GBM, IDH wild type, WHO grade 4 with extensive GC change. After resection of the enhancing lesion, the patient received concurrent tumor-treating fields (TTFields) with radiation and temozolomide, enrolled in SPARE trial (NCT03477110). The patient had rapid response in the areas of gliomatosis change demonstrated on the magnetic resonance imaging 1 month post-radiation treatment. The response of GC is durable. He recurred 11 months after surgery with new enhancing lesions, treated with radiosurgery. He had further extensive progression of enhancing lesions 13 months after surgery, and received bevacizumab treatment. Patient ultimate passed away 17 months after surgery. Despite progression of enhancing lesions, GC remained controlled. He also had favorable progression-free survival of 11 months and overall survival of 17 months. Conclusions: This case serves as an example of how combination TTFields with chemoradiation may elicit a durable response of GC in patients with GBM.