Cranial Spinal Spreading of Canine Brain Gliomas after Hypofractionated Volumetric-Modulated Arc Radiotherapy and Concomitant Temozolomide Chemotherapy: A Four-Case Report

Abstract

Gliomas are the second-most-common primary brain tumors in dogs. Surgery and radiotherapy are established treatment approaches with similar median survival time, whereas conventional chemotherapy is burdened by severe adverse effects. Spinal and leptomeningeal spread of gliomas have been described following radiotherapy treatment alone. The purpose of this study was to evaluate the outcome for four dogs with primary high-grade gliomas in the forebrain without evidence, at diagnosis, of neoplastic invasion along the spinal cord, that were treated with concomitant chemotherapy (temozolomide) and hypofractionated volumetric-modulated arc radiotherapy (VMAT-RT). Temozolomide was selected for its radiosensitive properties, and radiotherapy dose protocols of 37 Gy in 7 fractions or 42 Gy in 10 fractions were used. After an initial complete or partial response, tumors recurred across the cranial–spinal pathway. Post-mortem macroscopic examinations confirmed swollen spinal cord and hyperemic meningeal sleeve, with nodular lesions on the meningeal surface. Microscopically, infiltration of the spinal cord and meninges by neoplastic cells (with features of oligodendrogliomas) were observed. This work seems to suggest that the entire central nervous system should be investigated in diagnostic examinations of canine gliomas. Dose-escalation trials and/or spinal cord prophylaxis treatment could also be evaluated to prevent tumor progression.

Precise Control of Glioma Cell Apoptosis Induced by Micro-Plasma-Activated Water (μ-PAW)

“…There are also scholars, such as Rühm et al, who used molecular stereotactic biopsy to accurately locate gliomas [19]. However, the current comprehensive treatment has certain side effects, such as incomplete removal by surgery, destruction of functional areas, and indiscriminate killing of normal nerve cells and glioma cells by radioactive elements during radiation therapy [20,21]. Chemotherapy, in contrast, is not only limited by the drug tolerance of glioma (e.g., platinum-based chemotherapeutic agents, a class of chemotherapeutic agents that affect the cell cycle, are not effective, because gliomas are resistant to platinum-based drugs [22]) but also decreases neurocognitive and other functions [23,24].…”