Glioblastoma is considered the most aggressive tumor that can form in the brain. Senator John McCain was diagnosed in July 2017.
According to figures, patients have a 10 percent chance of survival five years after their diagnosis. The average lifespan is between 14 and 16 months.
Three adults in every 100,000 will be affected by glioblastoma, says the American Association of Neurological Surgeons (AANS).
It is most common in men between the ages of 50 and 60, and there is no link between developing glioblastoma and having a history of other cancers.
WHAT IS THE TUMOR MADE OF?
The tumor consists of a mass of cells that grows rapidly in the brain, and in most cases, patients have no family history of the disease.
The disease does not spread to other organs, but once diagnosed it is almost impossible to target, surgeons claim.
Unlike other types of brain cancer that are more specifically localized, glioblastoma can occur in any part of the brain.
WHAT TREATMENT IS AVAILABLE?
Because the tumor has likely spread deep into the brain by the time it is diagnosed, the cancerous tissue is incredibly difficult to remove.
The surgeon will only remove the tumor, or part of the tumor, if it is not causing damage to the surrounding brain tissue.
Dr. Babcar Cisse, a neurosurgeon at the Weill Cornell Brain and Spine Center, told Daily Mail Online in July 2017: ‘By the time a glioblastoma is diagnosed, microfibers can spread to the rest of the brain, which an MRI would not detect .
“So even if the main tumor is removed and the patient gets radiation and chemotherapy, it will come back.”
EVALUATING A GLIOBLASTOMA
Brain tumors are classified from one to four depending on how quickly they grow and how aggressive they are.
Malignant tumors are given a high grade of three or four, while benign tumors are given a lower grade of one or two.
Glioblastoma is often called a grade four astrocytoma – another form of brain tumor, says the AANS.
SYMPTOMS
Patients typically complain of symptoms such as blurred vision, memory problems, dizziness and headaches.
Symptoms are somewhat nonspecific, vary from person to person, and may not last.
Some patients suffer blindness when the tumor compresses their optic nerve, which connects the retina to the brain, resulting in vision loss.
The disease is therefore impossible to diagnose based on symptoms alone.