The ability to predict how a tumour will behave is a critical part of planning treatment.
The grade of a tumour — a category assigned based on how aggressive the cancer is expected to be — can help. However, sometimes these categories do not reliably capture the behaviour of a tumour, which can make predicting patient outcomes and planning appropriate treatment a challenge.
Clinicians have long faced these issues when grading meningiomas, tumours that come from the membranes that surround the brain and spinal cord, which is called the meninges.
In a new study from UHN's Princess Margaret Cancer Centre, researchers may have found a way to resolve this issue and make grading meningiomas significantly more reliable.
The team, led by Dr. Gelareh Zadeh, an affiliate scientist at the Princess Margaret, and Dr. Farshad Nassiri, who is a scientist there, found that meningiomas with certain chromosomal changes called copy number alterations (CNAs) — in particular a 1p loss (a loss of the first half of chromosome 1) or 1q gain (a copy gain in the latter half of chromosome 1) — behave more aggressively than their grade would predict.
As a result, these tumours may not be receiving the best treatment, negatively impacting patient outcomes.
"Improving care for patients begins with ensuring that we accurately evaluate their tumour and predict how it will behave," says Dr. Nassiri, a co-senior author of the study who is also a neurosurgeon in UHN's Sprott Department of Surgery and Toronto Western Hospital, and an assistant professor in the Faculty of Medicine at the University of Toronto (U of T).
Dr. Alexander Landry, one of the study's first authors and a graduate researcher at the Princess Margaret as well as PhD candidate and neurosurgery resident at U of T, says: "We've been studying genetic changes in meningiomas and how they impact tumour biology for years but translating these discoveries has proved to be a challenge thus far."
This work highlights the critical need to improve the WHO grading system for CNS tumours like meningiomas, such as by incorporating genetic features like CNAs into grading criteria. Because meningiomas are one of the most common types of brain cancer in adults, rectifying the inconsistency in the current system could significantly improve care for a large population of patients with a challenging diagnosis and offer more patients a better chance at life after meningioma.
"Our work offers a way to improve meningioma grading in clinical practice today without requiring tests that are impractical in most cancer care settings because they're prohibitively expensive or need specialized technology and staff not available everywhere," says Dr. Zadeh, a co-senior author of the study who is also a neurosurgeon in the Faculty of Medicine at the University of Toronto and the Chair of Neurosurgery at the Mayo Clinic.
This work was supported by the International Consortium of Meningiomas, Brain Tumour Charity UK, CCS, Canadian Institutes of Health Research and The Princess Margaret Cancer Foundation.
