As you may have heard, news was released that Senator John McCain has brain cancer, more specifically a glioblastoma. Dr. Singh Sahni, medical director of neuroscience at the Sarah Cannon Cancer Institute at Johnston-Willis Hospital addresses key questions about this diagnosis below.
What is a glioblastoma?
It is a malignant primary brain tumor, originating from cells in the brain called astrocytes. Glioblastoma is abbreviated as GBM also may be called glioma, glioblastoma multiforme, and grade IV astrocytoma.
It has been reported that Sen. 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 2 to 3 per 100,000 people in United States are diagnosed with this type of cancer. This tumor may be seen at any age but incidence is higher for people between the ages of 45-75, and also for men. Glioblastomas account for almost 15 percent of all intracranial tumors in adults.
What are the symptoms?
Symptoms depend on the location of the tumor. If it 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?
There is no specific cause or risk factors known.
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, and often a second surgery and/or stereotactic radiosurgery such as what we do with Gamma Knife 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.