Mayo Clinic expert describes 3 common brain tumors and their treatment

By Jessica Saenz

The term "brain tumor" is often used interchangeably with "brain cancer." And while brain tumors can sometimes be cancerous, most of the time they're not, according to the National Brain Tumor Society.

Beyond malignant and benign, brain tumors can be classified as primary if they formed in the brain or metastatic (secondary) if they spread from cancer that began somewhere else in the body.

These characteristics extend to more than 150 types of documented brain tumors. Mayo Clinic neuro-oncologist Wendy Sherman, M.D., talks about the most common types.

Benign brain tumor: Meningioma

The brain and spinal cord are surrounded by protective membranes called the meninges. When a tumor grows within this membrane, it is called a meningioma. Though meningiomas can be malignant, the most common subtype of meningioma is benign.

"The majority of these are slow-growing tumors, but a small portion of them is faster growing," says Dr. Sherman. Because most meningiomas grow slowly, they often don't cause symptoms and they can go unnoticed. But when meningiomas grow large enough, or near parts of the brain that help control the body, they can cause a wide variety of symptoms including vision changes, loss of smell or taste, memory loss and seizures.

Meningiomas also can be hard to diagnose, but if your healthcare professional suspects you may have one, imaging tests like CT scans or MRIs can help identify the location and size of a tumor.

Treating meningioma

"The treatment depends on what type of meningioma it is," says Dr. Sherman. "When someone has surgery for a meningioma, we assign the tumor a grade. The grade defines how fast it's likely to grow or if it's likely to recur after surgery."

Dr. Sherman says with slow-growing, low-grade meningiomas, surgery and monitoring are often the most efficient treatment, but higher-grade tumors may require radiation instead of surgery or a combined approach. "If we start to see recurrence over time, then we consider additional surgery or focused radiation like Gamma Knife radiosurgery, which is a very specialized, focused radiation," says Dr. Sherman.

"There are a lot of different factors we consider when we're making up the treatment plan," says Dr. Sherman. "It's a joint decision made by our multidisciplinary team of neurosurgery, neuro-oncology, radiation oncology and neuropathology. We all look at the case together and figure out the best way to treat that patient."

Malignant brain tumor: Glioblastoma

"The most common malignant tumor that's found in the brain is something called a glioblastoma, which is a type of tumor called a glioma," says Dr. Sherman. This aggressive form of cancer can also develop in the spinal cord and can cause symptoms like headache, nausea, vomiting, memory loss, speech difficulty or personality changes.

Glioblastoma, also known as glioblastoma multiforme, accounts for 50% of all primary malignant brain tumors and the five-year survival rate is 6.9%, according to the National Brain Tumor Society. Though glioblastoma is rare, Dr. Sherman says cases of this type of cancer have risen recently.

"Typically, when patients have glioblastoma, it's a pretty rapid diagnosis. Their symptoms occur over days to weeks. They get a scan and then, oftentimes, they're taken very quickly to surgery to get it removed," says Dr. Sherman.

Treating glioblastoma

Treatment for glioblastoma can include surgery, radiation therapy, chemotherapy or targeted therapy treatments that focus on specific characteristics of the cancer cells. If your tumor is causing symptoms, you may also receive treatment to ease them.

If surgery is done as part of the treatment, Dr. Sherman says, it's not a final step. "Even if you remove everything you can see with your eye, there are still tumor cells that remain and require further treatment. So, after people have surgery, they heal and recover and then we treat them with radiation along with chemotherapy, which is typically given in pill form."

To improve the effectiveness of chemotherapy, a treatment called tumor treating fields therapy — which delivers electrical energy to the tumor through sticky pads attached to the head — can be given at the same time as chemotherapy. This treatment works by weakening the glioma cells and making it more difficult for them to reproduce.

While treatment can slow progression and improve symptoms, Dr. Sherman says there is no cure for glioblastoma. "Even with aggressive therapy, on average patients live somewhere between one year to three years from the time of diagnosis," she says. "That's the reason we are so dedicated to our research efforts to find innovative treatments for glioblastoma and eventually a cure."

Secondary brain tumor: Metastatic breast and lung cancer

A brain tumor that didn't originate in the brain is called brain metastases or a secondary tumor. Up to half of metastatic brain tumors are from lung cancer, according to the National Cancer Institute. Others commonly spread from the breast, colon, kidney, the upper part of the throat behind the nose (nasopharynx) or melanoma, although any type of cancer can spread to the brain.

Like primary tumors, a secondary tumor can grow and create pressure on parts of the brain that control important functions. This can result in symptoms similar to those of primary tumors. But because the tumor can develop from cancer cells that break off from other tumor sites in the body, the cells can spread and develop into multiple tumors around the brain.

In some cases, cancer cells leave the original site of the cancer and travel to the fluid around the brain or the lining that surrounds the brain rather than the brain itself. This rare form of metastatic disease is called leptomeningeal metastasis, and is most common in people with breast cancer, lung cancer and melanoma, according to the National Cancer Institute.

"What happens is these cancer cells can leave their site where they started, and they invade the fluid that surrounds the brain and the spine, which is in a sack called the meninges. These cancer cells can float around in this fluid and latch onto things around it," says Dr. Sherman.

Treating secondary brain tumors

To determine the best treatment for you, your healthcare professional first must be certain of the origin of your tumor — whether it's a primary tumor or secondary tumor. The number of tumors, type, size and location will also help your care team determine your course of treatment.

Treatment for secondary brain tumors is similar to treatment for meningioma and glioblastoma and can include surgery, radiation, chemotherapy or targeted drugs.

Dr. Sherman says treatment for leptomeningeal metastasis needs to be improved. "There is really a dedicated effort to finding better treatments that can put chemotherapy or other drugs directly into the fluid through a special port that's placed in the head," says Dr. Sherman. "And that allows you to really saturate those cancer cells in the fluid with the drug of choice. A lot of trials right now are looking at what drugs we should be using, how we should be giving them and how we can monitor their effectiveness."

Learn more

Learn more about brain tumors and find an brain tumor clinical trial at Mayo Clinic.

Join the Brain Tumor Support Group on Mayo Clinic Connect.

Also, read these articles:

• "What’s a pituitary tumor? 4 things you need to know"
• "Brain tumors: What you should know"
• "How Gamma Knife surgery treats brain tumors"
• "Making progress in treating glioblastoma"
• "Glioblastoma in older adults: Improving survival and quality of life"