John McCain, Arizona senator diagnosed with glioblastoma brain tumor

Senator John McCain, 80, Republican from Arizona, was recently diagnosed with glioblastoma, a cancerous brain tumor that appears to be associated with a blood clot found above his left eye that was removed a week ago.  McCain, a prisoner of war in Vietnam and a two-time presidential candidate, has faced many health challenges in the past such as having a history of melanoma, a dangerous form of skin cancer.  He is well-known for his extraordinary courage that has characterized his life and career and will be well-prepared to fight this new threat with the same kind of tenacity and strength he has always demonstrated over the years.

At this time, all of us wish Senator McCain the best of luck in fighting this latest medical opponent he faces and send our prayers of support for a fast and successful recovery along with his family, medical team and the nation. 

Much of the public may not be as familiar with this type of cancer.  Here are some basic facts on glioblastomas and what we all need to be aware of about this condition:

What is a glioblastoma?

Every year, 8.2 of every 100,000 people in the U.S. are diagnosed with primary malignant brain tumors which represent about 2% of all cancers diagnosed in the country.  Around 12,000 people in the U.S. are diagnosed with a glioblastoma which occur in the brain and are considered a grade IV tumor.  They are considered the most aggressive and deadliest form of primary brain tumor and can spread into other parts of the brain very quickly but do not metastasize outside of the brain.  What makes them more deadly is that they can make their own blood supply which helps them grow making it easier for them to invade normal brain tissue. They commonly are found in the frontal temporal lobes of the brain, but can occur in any lobe of the brain including the brain stem and cerebellum. 

This type of brain tumor represents about 15.4% of all primary brain tumors and about 60-75% of all astrocytomas.  

Is it known what causes glioblastomas and are there risk factors?

Glioblastomas are considered more common in men, they tend to increase in risk in people over the age of 50, and are found more frequently in individuals who are of Caucasian or Asian ethnicity.  Only 3% of childhood brain tumors are glioblastomas.  The only known risk factor for brain tumors is radiation exposure otherwise there are a few very rare familial syndromes associated with brain tumors.

What are the symptoms and how are they diagnosed?

Depending on the location of the tumor will determine an individual’s symptoms.  Because glioblastomas can grow rapidly, the most common symptoms are usually caused by increased pressure in the brain. The symptoms can include headaches, nausea, vomiting, or seizures.  Sometimes these tumors can result in subtle personality changes and memory loss, muscle weakness, and changes in one’s speech.  For some, there may be no symptoms and they may be found accidentally when a brain scan is performed for another reason.

Most patients receive a diagnosis of a glioblastoma by having a CT scan followed by MRI.  To get a pathological diagnosis, tissue is removed during surgery and is examined by a neuropathologist who will make the determining diagnosis.

Treatments options for glioblastoma’s

The first step in treating glioblastoma is to relieve pressure on the brain by safely removing as much of the tumor as possible through a surgery called maximal safe resection.  Glioblastomas have finger-like tentacles which can be very difficult to completely remove and especially so if they are growing near the parts of the brain that control important functions such as language and coordination.  Glioblastomas are not cured by having surgery but the more tumor that can be removed, the better the prognosis.  After surgery, there will be follow-up treatments of radiation and an oral chemotherapy.  The radiation and chemotherapy are meant to target the infiltrative component of the glioblastoma and to delay progression of the tumor.

What is the outlook for someone with a glioblastoma?

The prognosis for someone with a glioblastoma can vary.  Adults who have been given a diagnosis of aggressive glioblastoma, the median survival is about 14.6 months with a two-year survival of 30%.  However, a 2009 study reported that almost 10% of patients with glioblastoma may live five years or longer.