Glioblastoma

Overview

Glioblastoma is an aggressive cancer that begins in the brain. It develops from glial cells, the supportive cells that surround and help nerve cells function. Classified as a grade 4 tumor, the highest grade, glioblastoma grows quickly and tends to spread into nearby brain tissue, which makes it difficult to remove completely.

Glioblastoma is the most common malignant primary brain tumor in adults, meaning it starts in the brain rather than spreading there from elsewhere. It can occur at any age but is most common in older adults. Although it is a serious diagnosis, treatment can help control the tumor, relieve symptoms, and extend and improve quality of life. Care is highly individualized and provided by a team of specialists.

Symptoms

Symptoms depend on the tumor's size and location and often develop and worsen over weeks. They can include:

• Headaches that are new, persistent, or worse in the morning
• Nausea and vomiting
• Seizures
• Weakness or numbness on one side of the body
• Problems with vision, speech, or balance
• Confusion, memory problems, or changes in thinking
• Changes in personality or mood
• Increasing drowsiness

Because glioblastoma can raise pressure inside the skull, symptoms such as a rapidly worsening headache, repeated vomiting, increasing drowsiness, or new weakness need prompt medical evaluation, and sudden severe symptoms warrant emergency care.

Causes

The exact cause of glioblastoma is not known. It arises when glial cells develop genetic changes that cause them to grow and divide uncontrollably, forming a tumor. Unlike some cancers, glioblastoma is usually not linked to a clear, modifiable cause.

• Genetic changes: Mutations in the tumor cells drive its growth, but these usually arise during life rather than being inherited.
• Radiation exposure: Previous radiation to the head is one of the few recognized risk factors.
• Rare inherited syndromes: A small number of cases are linked to genetic syndromes that increase cancer risk.

For most people, no specific cause can be identified, and glioblastoma is not something a person can be blamed for or could have prevented.

Risk Factors

• Increasing age, with the highest rates in older adults
• Previous radiation therapy to the head
• Rare inherited conditions that increase cancer risk
• Being male, as glioblastoma is somewhat more common in men

Most people with glioblastoma have no identifiable risk factors, and everyday exposures have not been proven to cause it.

Diagnosis

Diagnosis usually begins when symptoms prompt brain imaging. Steps include:

• Neurological examination: Testing vision, strength, balance, reflexes, and thinking.
• Brain imaging: MRI, often with contrast, is the main tool to find a brain tumor and show its size and location; CT may be used as well.
• Biopsy or surgery: A sample of the tumor is examined under a microscope to confirm it is glioblastoma and to study its features.
• Molecular testing: Analyzing the tumor's genetic and molecular markers, which can guide treatment and provide information about prognosis.

Treatment

Treatment is tailored to the individual and usually combines several approaches:

• Surgery: Removing as much of the tumor as is safely possible, which can relieve symptoms and improve other treatments. Because glioblastoma spreads into surrounding tissue, surgery rarely removes every cancer cell.
• Radiation therapy: Targeted radiation to the tumor area, usually after surgery.
• Chemotherapy: Medication, often given with and after radiation, to slow tumor growth.
• Other therapies: Tumor-treating fields and clinical trials of newer treatments may be options for some people.
• Supportive care: Medications to control seizures and brain swelling, and care to manage symptoms and support quality of life.

Because glioblastoma often returns, ongoing monitoring and additional treatment are common. A team of specialists works with the patient and family to choose treatment that fits their goals.

Prevention

There is no known way to prevent glioblastoma, since its cause is usually unknown and not tied to lifestyle. General steps that support overall health may help, but they do not specifically prevent this tumor:

• Avoid unnecessary radiation exposure to the head when possible
• Seek prompt evaluation for persistent or worsening neurological symptoms
• Discuss genetic counseling if a rare cancer syndrome runs in your family

When to See a Doctor

See a doctor if you have new, persistent, or worsening neurological symptoms, such as ongoing headaches, vision or speech problems, weakness, or changes in thinking or personality. Seek emergency care right away for:

• A first-time seizure
• A sudden, severe headache
• Sudden weakness, numbness, or trouble speaking
• Repeated vomiting with headache or increasing drowsiness

These symptoms have many possible causes, and prompt evaluation helps identify the problem and start any needed treatment quickly.

Related Topics

Frequently Asked Questions

References

1. National Cancer Institute (NCI). Adult central nervous system tumors.
2. American Brain Tumor Association. Glioblastoma.
3. Mayo Clinic. Glioblastoma.
4. MedlinePlus, U.S. National Library of Medicine. Brain tumors.