Dr Brastianos Breaks Down the Basics of Meningiomas

Priscilla K. Brastianos, MD, explains the differences between low-grade meningiomas and aggressive high-grade tumors.

Meningiomas are the most common type of brain cancer—the American Society of Clinical Oncology estimates that the disease represents approximately 40% of primary brain tumors and will affect 42,260 people in the United States in 2023.

Priscilla K. Brastianos, MD, an associate professor of medicine with Harvard Medical School and a physician-scientist at Massachusetts General Hospital Cancer Center, investigates the genomic drivers of human brain tumors. She notes that the disease arises in the meninges, which are layers of membranes surrounding the spine and brain.

The World Health Organization (WHO) says approximately 80% of these tumors are benign, or grade I. Brastianos says that many low-grade tumors are indolent and can be fully resolved with resection. Some do not require immediate treatment. Tumors that are asymptomatic, small, and slow growing can be “treated” with observation alone.

However, the remaining 20% of tumors are grade II, which are more likely to recur following treatment, or grade III, which are both malignant and more likely to recur. Brastianos says that the WHO has identified molecular biomarkers, including TERT promoter mutations and CDKN2a status, that are associated with high rates of progression and poorer survival in patients with high-grade tumors. Recurrence in grade III meningiomas can be as high as 90%.

The WHO defines high-grade tumors as those that have “20 or more mitosis per 10 high-power field, malignant characteristics resembling carcinoma, sarcoma, or melanoma; or a high-risk molecular feature.”

Prognosis depends on a variety of factors including tumor size, location, and grade, she says. Survival is shorter in those with grade II/III tumors. CDKN2 loss and alterations in TERT promoter are also associated with poorer survival, Brastianos says.

Currently, there is no systemic therapy available for high-grade meningiomas. Brastianos said treatment consists of multidisciplinary teams including surgery and radiation. Patient factors such as age and comorbidities play a role in treatment decisions, she concludes.