Lay Abstract:
Intracranial meningiomas are the most frequent brain tumors in dogs. Despite their generally benign nature, progressive growth causes life-limiting clinical signs that make treatment essential. Radiotherapy represents the most effective single-treatment modality for canine meningiomas, offering acceptable survival times, and rapidly restoring an excellent quality of life for most patients. Nevertheless, dogs show different responses to radiotherapy. Some patients achieve long lasting tumor control, others show early disease progression and recurrence of clinical signs. This suggests that there may be tumor subtypes that are causative for these differences in treatment response. Recent research has found 3 different types of meningiomas in dogs, including one that shares high similarity with human `MenG C`subtype. In humans this tumor subtype does not respond as well to radiotherapy. In dogs, this has not yet been evaluated. Identification of radioresistant meningiomas is pivotal to develop individualized treatment protocols specifically adapted to this underserved patient population.
In this prospective clinical study, minimally invasive stereotactic brain biopsies will be used to obtain treatment-naïve tumor tissue from 36 dogs with meningiomas for RNAsequencing (RNAseq) and histopathology. Patients will subsequently undergo radiotherapy (10x4Gy with simultaneously integrated boost (SIB)) and followed-up with regular imaging thereafter for at least 12 months. RNAseq will allow identification and confirmation of molecular subtypes of canine meningiomas (Objective 1), while assessment with clinical outcome will investigate their influence on radio response (Objective 2). This study holds immense potential to deliver first data for future studies for individualized and improved treatment approaches for dogs with meningiomas.