We recently learned Senator John McCain has brain cancer, more specifically a glioblastoma. Dr. Craig Kemper, a neurosurgeon at St. David’s Medical Center, answers some key questions about this diagnosis below.
What is a glioblastoma?
Glioblastoma is a malignant primary brain tumor, originating from cells in the brain called astrocytes. Glioblastoma is abbreviated as GBM – it also may be called glioma, glioblastoma multiforme and grade IV astrocytoma.
It has been reported that Senator McCain has a primary tumor. What does that mean?
A “primary” brain tumor means that the tumor originated in the brain. Metastatic brain tumors develop from cancer cells that originated in other organs, such as the lungs, and then metastasized to the brain.
How common is a glioblastoma?
Approximately two to three per 100,000 people in the United States are diagnosed with this type of cancer. This tumor may be seen at any age, but the percentage is higher for people between the ages of 45-75. Glioblastoma tumors are also more common in men than in women. Glioblastomas account for nearly 15 percent of all intracranial tumors in adults.
What are the symptoms?
Symptoms of this type of cancer depend on the location of the tumor. If the tumor sits in the portion of the brain responsible for the arm and leg strength called the “motor strip,” then the patient may notice weakness in the arm or the leg on the opposite side from the location of the tumor in the brain. Left temporal lobe tumors in right-handed people may cause speech deficits. The onset of seizures can also indicate a tumor in the brain. Speech and cognitive impediments may also be a manifestation of swelling which happens as a result of glioblastoma tumors.
How is it diagnosed?
Glioblastoma can be diagnosed through imaging of the brain. A definitive diagnosis is typically made through a needle biopsy or open surgery called craniotomy.
Are there any known risk factors?
Radiation is a known risk factor. There can also be a familial tendency to develop these. As research goes on, we are identifying more potential causative agents.
How do you treat a glioblastoma?
Standard therapy for glioblastomas may include surgical resection followed by radiation. Standard therapy also includes Temodar (temozolomide) in combination with radiation.
Glioblastoma tumors have a high recurrence rate. Often a second surgery and/or stereotactic radiosurgery, such as what we do with gamma knife or cyberknife – a tool that provides extremely precise radiation beams that target and destroy brain tumors and other diseased tissue, may be part of the treatment plan.
There are advancements in the treatment of brain cancers being made. Molecular profiling, which analyzes biomarkers that may contribute to the diagnosis of the tumor and response to therapy, new-targeted therapies and immunotherapies all play a role in the approach Sarah Cannon takes to treat these tumors.
Image credit: Gage Skidmore
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