Glioblastoma (GBM)

What is glioblastoma?

Glioblastoma (GBM) is the most common type of malignant (cancerous) brain tumor in adults. It starts in a type of glial cell in your brain and spinal cord called astrocytes. Cancer cells rapidly grow and multiply. They can spread into other areas of your brain and spinal cord. Rarely, cancer spreads beyond these areas.

Glial cells, including astrocytes, are vital to help nerve cells function. GBMs are the fastest-growing astrocytoma (a tumor that forms in astrocytes).

Glioblastoma, formerly known as glioblastoma multiforme, is a devastating type of cancer that can result in death in fewer than six months without treatment. More than 13,000 Americans are diagnosed with GBM every year.

If you notice any symptoms like vision changes, memory problems, headaches or seizures, visit a healthcare provider as soon as possible.

Symptoms of glioblastoma

Glioblastoma symptoms may include:

• Blurred or double vision
• Headaches
• Loss of appetite
• Memory problems
• Mood or personality changes
• Muscle weakness or balance issues
• Nausea and vomiting
• Seizures
• Speech problems
• Changes in sensation, numbness or tingling

Glioblastoma symptoms tend to come on quickly. The growing tumor puts pressure on your brain and can destroy healthy brain tissue.

Glioblastoma causes

Researchers don’t know the exact cause. Like other gliomas (tumors that form in your brain and spinal cord), researchers suggest that changes in your DNA lead to the development of glioblastoma brain tumors. Your genes contain DNA. They give instructions to your cells about how to grow and multiply. Mutations, or changes, to the DNA in your genes can cause cells to multiply out of control.

Is glioblastoma hereditary?

It’s possible to inherit genetic variations from your biological parents. But inherited GBMs are rare. Most commonly, these mutations happen randomly during your lifetime.

Risk factors of glioblastoma

Glioblastoma most often affects people ages 45 to 70. The average age at diagnosis is 64.

These factors may increase your risk:

• Exposure to chemicals, like pesticides, petroleum, synthetic rubber and vinyl chloride
• Genetic, tumor-causing conditions, like neurofibromatosis, Li-Fraumeni syndrome and Turcot syndrome
• Previous radiation therapy to your head

Complications of glioblastoma

Glioblastoma and its treatments may affect brain function. You could experience mood changes and memory problems. Most people with GBM eventually have to stop working and driving. You may need full-time care. These changes could lead to anxiety disorders or depression.

How doctors diagnose glioblastoma

A healthcare provider will evaluate your symptoms and perform a neurological exam. If they suspect you may have a brain tumor, you may have these tests:

• MRI or CT scan to look for brain tumors
• Biopsy to get a sample of a tumor and examine the tissue for cancer cells

What are the grades of glioblastoma?

Healthcare providers use a grading system from I (1) to IV (4) to indicate brain tumor behavior. Grade I brain tumors grow slowly and are the least aggressive. Grade IV tumors grow rapidly and are more aggressive. Glioblastoma tumors are grade IV.

Glioblastoma can be either primary or secondary:

• Primary GBM. It develops directly from glial cells.
• Secondary GBM. Grade I glial tumors progress to become GBMs.

How is glioblastoma treated?

Treatment may include tumor removal surgery (craniotomy), radiation and chemotherapy. If surgery isn’t a safe option, your care team may suggest radiation and chemotherapy to try to manage the tumor.

Glioblastoma treatment options include:

• Radiation therapy. Uses X-rays to damage cancer cells. You may need up to 30 daily treatments over six weeks.
• Intensity-modulated radiation therapy (IMRT). Delivers radiation to the tumor while sparing healthy brain tissue.
• Stereotactic radiosurgery (Gamma Knife). Uses focused energy beams to target the tumor with minimal damage to healthy tissue. Often used if GBM returns after IMRT.
• Chemotherapy. Circulates medication in your bloodstream to kill cancer cells. Often combined with radiation and continued afterward.
• Laser interstitial thermal therapy (LITT). Uses laser energy to destroy the tumor.
• Targeted therapy. Targets certain cell changes that fuel cancer growth. It’s an alternative to chemotherapy.
• Tumor treatment fields (TTF). Sends low-intensity electric fields to the tumor via scalp electrodes that disrupt cancer cell growth. Often used after chemo-radiation.
• Immunotherapy. Uses your body’s immune system to fight the GBM cells.
• Palliative care. Provides symptom relief and emotional support.

There isn’t a cure for glioblastoma.

When should I see my healthcare provider?

You should call your healthcare provider if you experience:

• Memory problems
• Seizures
• Severe headaches or vision issues
• Unexplained weight loss or nausea and vomiting
• Change in personality
• Progressively worsening weakness, numbness or speech problems

Can glioblastoma be prevented?

Genetic mutations that cause glioblastoma aren’t preventable. But early detection and treatment may slow the progression of a tumor.

If brain tumors run in your biological family, you may want to consider genetic testing. Talk to a healthcare provider or a genetic counselor about the risks and benefits of genetic testing.

Glioblastoma prognosis

Glioblastoma may result in early death shortly after a diagnosis without treatment. But treatments are available. They may help you ease symptoms and stay comfortable or prolong your life.

Clinical trials are underway to find new treatments. And therapies that target specific cancer cell genes show promise. Researchers are also looking at ways to deliver chemotherapy directly to the brain tumor. Your provider will let you know if a clinical trial is right for you.

Most people live an average of 12 to 18 months after diagnosis. The five-year survival rate for glioblastoma is only about 5%. That means about 5% of people with GBM are still alive five years after their diagnosis.