• Mayo Clinic Minute: What are brain metastases?

Over one million people in the U.S. are living with brain tumors, and more than 90,000 new diagnoses are made each year.

Dr. Rich Byrne, a Mayo Clinic neurosurgeon, explains how brain tumors are classified and what that means for treatment.

Watch: The Mayo Clinic Minute

Journalists: Broadcast-quality video (1:00) is in the downloads at the end of this post. Please courtesy: "Mayo Clinic News Network." Read the script.

There are dozens of types of brain tumors, but generally, they are classified as primary or metastatic.

"A brain metastasis is a tumor that started elsewhere in the body that spread through the bloodstream and lodged itself in the brain," says Dr. Byrne.

This differs from a primary brain tumor, which starts in the brain and may require a different treatment approach.

Medical illustration of brain metastases
Brain metastases happen when cancer begins elsewhere in the body and spreads (metastasizes) to the brain.

"The different approaches that we take in treating brain metastases versus primary brain tumor depends on how many brain metastases there are because they often come in more than one and where they are and how large they are," says Dr. Byrne.

The tumor's location is also a factor in the treatment plan. A CT scan or MRI of the brain will confirm the diagnosis and create a road map for the care team to determine the next steps.

"After a patient is seen, and we do a history and physical exam and evaluate the imaging studies that they've had and any other data, then we come to the treatment plan," says Dr. Byrne. "And the treatment plan can vary from just watchful waiting and follow-up imaging all the way to a recommendation for radiation or surgery."

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