Improved outcomes for high-grade gliomas (HGG) require advances in our ability to monitor changes to tumour biology using non-surgical approaches. "Liquid biopsy" is a term used to describe a technique whereby tumour DNA, which has been shed off and then circulates through the blood stream, is detected and analyzed. Our goal is to develop a new type of liquid biopsy that is suitable for primary brain tumours that uses a method that is highly sensitive and allows for ongoing analysis of these tumours.

The study objective is to determine the feasibility of measuring both the burden and key molecular features of HGG through profiling of plasma circulating tumour DNA (ctDNA). This will be determined by detecting ctDNA in samples from HGG patients, and measuring changes in ctDNA levels over time following HGG treatment. 50 eligible patients will be enrolled in the study at University Health Network, and up to 10 blood samples will be obtained; up to 2 blood samples prior to their radiotherapy treatment, and 8 blood samples after their radiotherapy treatment. If available, tissue samples that are stored at UHN will also be collected for DNA extraction.

Inclusion Criteria:

• Patients can be enrolled either prior to a planned surgery/biopsy for a suspected HGG or after biopsy/surgery of pathologically proven, previously untreated HGG, prior to adjuvant radiotherapy
• Patient consent must be appropriately obtained in accordance with applicable local and regulatory requirements. Each patient must sign a consent form prior to enrollment in the trial to document their willingness to participate
• Age ≥18 yrs

Exclusion Criteria:

• History of another invasive malignancy, except for non-melanoma skin cancer or tumors curatively treated with no evidence of disease for ≥ 2 years.

Patients with suspected or pathologically-proven, previously untreated high grade gliomas

No plan to share.