Science

Deciphering Brain Tumors, Both Malignant and Benign  

During Brain Tumor Awareness Month in May, experts help educate everyone about a potentially frightening diagnosis. An estimated 700,000 Americans are living with a primary brain tumor. And an estimated 90,000 people will receive a primary brain tumor diagnosis in 2022.

Here’s a breakdown that may surprise many: About 71 percent of all brain tumors are benign and about 29 percent are malignant.


Michael McDermott, M.D., neurosurgeon and chief medical executive of Miami Neuroscience Institute.

“Every headache is not a brain tumor, but a headache that is persistent over five days, increasing in severity/duration and associated with nausea, vomiting — and worse in the morning than in the evening — should be seen by a medical professional,” said Michael McDermott, M.D., neurosurgeon and chief medical executive of Miami Neuroscience Institute, who is the world’s leading expert  (2012-2022) in meningioma, the most common primary brain tumor in adults.

The American Cancer Society estimates that about 25,050 malignant tumors of the brain or spinal cord will be diagnosed in adults and children in the United States this year, with about 18,280 people dying from these types of tumors. While these numbers seem high, the chance of developing a malignant tumor of the brain or spinal cord over your lifetime is less than 1 percent. In comparison, the risk of a woman developing breast cancer is 14 percent, and the risk of developing lung cancer is about 7 percent.

Most Commonly Diagnosed Primary Brain Tumor

Meningiomas represent about 1 out of 3 primary brain and spinal cord tumors. They are the most commonly diagnosed primary brain tumors in adults. And although they evolve in the meninges, the layers of tissue that surround the outer part of the brain and spinal cord, they are commonly described as brain tumors

“Technically, a meningioma is not a brain tumor because it does not start in brain tissue, but often is referred to as a brain tumor,” explains Dr. McDermott. “Meningiomas are usually not cancerous (benign) and don’t tend to spread to distant parts of the body. But, because of its location, a meningioma can still cause neurological problems. As these tumors grow, they can compress the brain and spinal cord, leading to serious symptoms.”


Most meningiomas are usually discovered after an MRI or CT scan that someone may undergo after complaining of headaches or seizures, or possibly after a head injury. Since meningiomas are commonly slow-growing tumors, they often do not cause noticeable symptoms until they grow to certain size. In extreme cases, these tumors can alter a person’s behavior and mood.

“I would say that the greatest proportion of meningiomas are discovered by chance,” explains Dr. McDermott. “Because of the wide availability of modern imaging, particularly with magnetic resonance imaging (MRI), studies are done for other reasons. That’s why these tumors are frequently discovered.”

Here are more insights from Dr. McDermott, who is considered the world’s top expert on meningiomas from 2010 to present by Expertscape, a physician-based organization that ranks physicians based on their impact on clinical research in their field.

Common Risk Factors for Brain Tumors?

“In general, 99.9 percent of brain tumors are sporadic and we don’t know why they occur. However, there are some genetic conditions that are known to be associated with brain tumors like neurofibromatosis (a genetic disorder that causes tumors to form on nerve tissue) and multiple endocrine neoplasia. Additionally, brain tumors can be associated with colon cancer and melanosis.”

Common Risk Factors For Meningiomas?

“There are risk factors for meningioma, which include prior history of radiation in the face or scalp as a child. So, if you had Acute Lymphoblastic Leukemia as a child and were treated with prophylactic cranial radiation, you would carry a 25-fold risk increase of developing meningioma later in adult life.

“Meningiomas are also twice as common in women than they are in men. For women, it’s an association, not a ’cause and effect,’ when they have a history of breast cancer, as they have the same chromosomal aberration. Additionally, there is a greater risk for meningiomas in patients who have a history of thyroid tumors or family history of meningioma.”

Treatments for Meningiomas? “The different forms of treatment include surgery, radiation therapy or radiosurgery at diagnosis. And each of those forms of treatment has a different risk profile. Even 50 percent of benign tumors that are totally excised will recur 25 years after diagnosis. So, the key thing is that if you treat a patient with a benign tumor, they have to be followed essentially for their lifetime to rule out recurrence.”

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