Glioblastoma: How This Malignant Brain Cancer Develops

Senator John McCain, a prisoner of war in Vietnam for five years, has had to rely on courage, strength and bravery throughout many events in his life. 

Now, the 80-year-old senator will have to summon his strength again as he faces another tough battle — brain cancer.

This week, McCain’s office announced he had been diagnosed with glioblastoma, a malignant brain tumor. Doctors discovered the tumor after McCain had surgery to remove a blood clot from his left eye. He then underwent surgery to remove the tumor and is currently recovering at his home in Arizona.

McCain and his family are discussing treatment options with his doctors, but he likely will have to undergo chemotherapy and radiation. Unfortunately, McCain is one of many people who will receive this diagnosis. According to the American Brain Tumor Association, there will be an estimated 12,390 news cases of glioblastoma diagnosed this year.

Glioblastoma typically originates in the brain or spinal cord and is an aggressive tumor.

To understand how this cancer develops, you need to understand the brain’s anatomy. Inside the brain, there are two categories of cells: neurons and glial cells, the latter of which are connective cells that provide structure and function to the brain. Of these glial cells, astrocytes are the most abundant. They are one of the few cells and cell lines inside the brain that can replicate. 

Because of this, the coating of these cells can go awry and that’s how an astrocytoma, a type of brain cancer, can form. An astrocytoma is a primary tumor that is diffused and infiltrated from the substance of the brain as opposed to a metastasis that comes from another part of the body. 

 This type of cancer doesn’t have stages, but rather grades. Glioblastoma, which is McCain’s diagnosis, is a Grade IV astrocytoma, meaning it is fast-growing and very aggressive.

People diagnosed with this cancer have specific symptoms. Forty to 50 percent of patients will have headaches, while the most common symptoms include seizure activity, some forgetfulness and focal weakness or numbness (impaired brain, nerve or spinal cord function). Visual defects, such as not being able to clearly see to the right or left, are another common symptom. When we see these symptoms this will prompt us to ask the patient to undergo a brain MRI. However, we can’t rely on MRI alone to make a diagnosis because the patient’s actual condition could be a different type of tumor, a metastasis, an abscess or another inflammatory condition.

If a patient is diagnosed with a glioblastoma, we then do screening for clinical research studies and do tissue banking, which is where we save some of the patient’s tumor tissue to aid in determining the best treatment options for that patient. We then talk to the patient about standard of care treatment, which typically includes oral chemotherapy and six weeks of radiation. During this time, we get more genetic profiling information about the tumor and see if we can individualize the treatment. Afterward, if things are going well and we follow the standard of care treatment, we continue oral chemotherapy and add a device called Optune, a therapy that involves placing adhesive patches on a patient’s head and connecting them to a device to deliver treatment that suppresses tumor growth around the clock. This treatment has been clinically proven to be a lower toxicity, higher efficacy therapy.

When possible, we’ll also try to remove as much of the tumor as possible. We typically involve a neurosurgeon early on in the process so that he or she can determine the maximum amount of the tumor that we can remove safely. 

With glioblastoma, a multidisciplinary, collaborative approach is critical. When someone is first diagnosed, it’s important they seek the opinion of a brain and spine tumor center that has neuro-oncologists available to help guide them. This way the brain tissues are analyzed, the standard of care can be approached in the most sophisticated way possible and patients can be screened for the best treatments available.

Taking this approach can help to extend someone’s life. Glioblastoma is a very aggressive cancer, but the prognosis can vary largely due to the location and geometry of the tumor, the genetics and genetic profiling of the tumor and based on the health and general condition of each patient. With glioblastoma, the median overall survivorship is 14-18 months.

At UF Health Cancer Center - Orlando Health, we are working hard every day to increase survivorship rates. We’ve participated in several research studies, including the ATTAC study

developed with University of Florida, which is offered at only three sites in the country. Through this study, we’ve developed a vaccine using the patient’s own blood cells that targets a particular virus signature called CMVA. As part of this approach, we also profile a patient’s tumor tissues and administer vaccines throughout their treatment in addition to the standard of care. We’ve seen very good preliminary results from this study, so we’re excited to offer this option to patients.

The Cancer Center also participates in a National Cancer Institute Consortium effort called the Brain Tumor Treatment Collaborative Group, where we offer clinical research studies through the group, including vaccine studies and other targeted agent strategies.

 And as we’ve discussed with Optune, we’re also focused on low toxicity, more effective treatments.

 At UF Health Cancer Center - Orlando Health, we have a Brain and Spine Tumor Center that serves both adults and children. Our approach involves a very sub-specialized, multidisciplinary effort. Along with this, we also have research and tissue collection efforts that are paving the way for more effective treatments for today’s patients — and those that may be diagnosed in the future. We’re applying all the latest modalities and treatments to help patients, because we understand just how difficult this diagnosis can be. 

 Thousands of people will be diagnosed with glioblastoma this year, but we are slowly but surely making advances in treatment that can lengthen survivorship for patients. Decades ago, only up to 2 percent of patients with this disease survived two to three years. Today, a quarter of patients will live at least three to five years. With more clinical research and greater collaboration across disciplines, we can make even more progress and save more lives.