Thursday, July 27, 2017
Sen. John McCain of Arizona recently announced that he has a brain tumor called glioblastoma. Aaron Cohen-Gadol, M.D., M.Sc., professor of neurological surgery at IU School of Medicine and a clinician at the IU Simon Cancer Center, answered questions about brain cancer and glioblastoma.
Are brain tumors and brain cancer the same thing?
They are not; not all tumors are malignant. In 2016, nearly 80,000 people were diagnosed with primary brain and central nervous system tumors and the majority of the tumors were not cancerous. According to the American Brain Tumor Association, in 2016 there were 53,000 people diagnosed with benign tumors and about 25,000 diagnosed with malignant tumors.
What is the most common malignant brain tumor?
The most common malignant brain tumor is glioblastoma multiforme (GBM), which develops from astrocytes, the star-shaped cells that form the supportive tissue of the brain. These tumors reproduce rapidly and usually are fed by a large number of blood vessels. They rarely metastasize to other parts of the body. The American Brain Tumor Association estimates that 12,390 new cases of GBM will be diagnosed in 2017.
What are the symptoms of a malignant brain tumor and how is a brain tumor diagnosed?
People with GBM and other brain tumors can suffer from headaches, weakness or numbness, fatigue, confusion and seizures. Hearing or vision loss also can be a symptom. When a brain tumor is suspected, patients undergo an MRI to diagnose and pinpoint the location. In some cases, GBM can be easily reached surgically and a biopsy also may be performed.
What are the treatment options for GBM?
Glioblastoma multiforme cannot be completely surgically removed because it invades the normal brain with finger-like extensions of malignant cells. GBM tumors also contain many different types of cells, some of which respond well to certain therapies while others do not. The first step in any treatment plan is to relieve pressure on the brain and remove as much of the tumor as is safely possible through surgery. Radiation and chemotherapy are then used to slow the growth and spread of the tumor.
Sen. John McCain has been diagnosed with a glioblastoma multiforme, as will more than 12,000 other Americans this year. Sen. McCain is 80-years-old; is that a normal age for development of this type of cancer? Who is most at risk?
GBM is most commonly diagnosed in people between the ages of 45 and 75, although about 3 percent of childhood brain tumors are glioblastomas. Although the cause of GBM is unknown, risk factors may include a genetic predisposition to the malignancy, as well as environmental and occupational exposures to agents such as radiation.
What is the life expectancy for patients with GBM?
The age and the functional status of the patient are two of the factors that play a role in longevity after diagnosis. Prognosis is usually stated in “mean survival” rates, which means an equal number of patients do better and an equal number do worse after a specified time. Patients who suffer from GBM have a mean life expectancy of 14.6 months. At two years, the mean survival rate is 30 percent.
I have heard that cancer can start in other organs and move or metastasize to the brain. Is that tumor the same thing as brain cancer and is it treated in a different way than tumors that originate in the brain?
Malignant tumors that originate in other organs and travel through the lymphatic system or blood supply to the brain account for the fastest growing rate of incidence of any tumor type. Referred to as brain metastasis or secondary brain tumor, metastatic brain tumors contain the same type of cancer cells found in the primary cancer site. Skin cancer (melanoma), lung cancer and breast cancer are the most frequent types of cancer to develop brain metastasis. A multidisciplinary team of neurosurgeons, oncologists and radiologists are involved in developing a treatment plan that may include chemotherapy, surgery, radiation or stereotactic radiosurgery.
Are there any promising new treatments available in clinical trials that could dramatically alter the quality or quantity of life issue for patients with glioblastoma or other brain cancers?
There are numerous clinical studies for GBM around the nation including studies at Indiana University Simon Cancer Center. Information on local trials can be found at Indiana CTSI Clinical Trials, and the American Brain Tumor Association’s TrialConnect can provide information on trials nationwide.
Is there an information resource that you frequently suggest patients check?
The American Brain Tumor Association is a highly regarded source. Other trusted sources of information are the American Cancer Society, the National Cancer Institute, the American Society of Clinical Oncology’s CancerNet, the U.S. National Library of Medicine’s MedlinePlus and National Institutes of Health sites.