Glioblastoma: What to know about the deadly cancer confronting John McCain and Susan Bayh

U.S. Senator Evan Bayh and his wife, Susan, are shown at the 2001 Democratic National Conversation at the NCAA Hall of Champions on July 15, 2001.

Editor's Note Aug. 26, 2018: Sen. John McCain died Sunday in his Arizona home. Susan Bayh observed her twin sons enlist in the military in an Indianapolis ceremony on Saturday.

On Tuesday former Gov. Evan Bayh announced that his wife, Susan, underwent surgery to treat a malignant brain tumor. 

Here’s what you need to know about glioblastoma, the type of cancer with which the former first lady was diagnosed and that Sen. John McCain also is battling. 

Question: What is glioblastoma?

Answer: A type of brain cancer, glioblastoma arise in the glial cells that comprise the brain’s supportive tissues. These cells which take their name from the Greek word for “glue” have a variety of responsibilities including helping to monitor the blood brain barrier and regulate blood flow to the brain. Because these cells have a steady blood supply and tend to reproduce rapidly, these tumors are often malignant. While they grow rapidly within the brain, it’s not common for them to spread to other parts of the body.

Q: What are common symptoms?

A: Symptoms can include headache, nausea, vomiting, drowsiness, weakness on one side of the body, difficulty with memory or speech, loss of appetite, seizures, and double or blurred vision.

“When you look at the brain, that is very very valuable real estate so essentially even a tumor occupying small space, can cause a lot of problems,” said Dr. Sumeet Bhatia, an oncologist with Community Health Network with an interest in brain tumors. “They don’t have to spread in order to cause problems.”

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Q: How is glioblastoma treated?

A: Surgery may be done, although often doctors are unable to remove the whole tumor because the tumor may sit too close to parts of the brain responsible for language and coordination and blend with normal brain tissue. In addition, the tumor often grows tentacles making it even harder for a surgeon to reach it all.

“It’s like cutting out an octopus; you’re almost never able to get all of the legs,” Bhatia said.

Surgery is usually followed with radiation and chemotherapy.

Q: Can glioblastoma ever be cured?

A: “Unfortunately we do not have a curative treatment for glioblastoma,” said Dr. Aaron Cohen-Gadol, director of neurosurgical oncology at the Indiana University School of Medicine as well as a neurosurgeon with the IU Simon Cancer Center and Goodman Campbell Brain and Spine. “The treatment primarily tends to temporarily control or slow the growth of the cancer.”

Q: What is the five-year survival rate for glioblastoma?

A: The prognosis for most patients is not good.

Untreated, patients with glioblastoma have a median survival rate of two to four months, Bhatia said. Median survival refers to the point at which half the patients diagnosed with that disease will still be alive.

For those who have the most aggressive form of the disease, the two-year survival rate is 30 percent, according to the American Brain Tumor Association. Those with a slower growing form of cancer may live about a year longer with the treatments available today.

The median survival rate is 14 to 15 months from the time of diagnosis, Cohen-Gadol said.

That means that half of the people live longer and it’s not unusual today to find someone living two to three years with the disease, Bhatia said.

Q: How common is glioblastoma?

A: About two to three of 100,000 adults per year are diagnosed with glioblastoma in the United States and Europe, according to the National Brain Tumor Society. Including children, nearly 11,000 people a year are diagnosed with glioblastoma.

Q: Are there certain risk factors for developing glioblastoma?

A: The primary known risk factor is previous exposure to radiation. Some studies have found a link between gliomas, a group of cancers that includes glioblastomas, and certain pesticides. There’s no known link between smoking, diet, or cell phone use and glioblastomas, Cohen-Gadol said.

Q: Are glioblastomas more common in certain people?

A: They occur more commonly in men than in women and become more common as people age.

Susan Bayh’s diagnosis makes her the fourth person associated with the U.S. Congress in some way to be diagnosed with the disease in the past decade. In 2009, Sen. Ted Kennedy died of the disease. Beau Biden, son of former Vice President and Senator Joe Biden, died six years later.

Last summer, Sen. McCain was diagnosed with glioblastoma.

Sources: American Brain Tumor Association, American Association of Neurosurgeons; American Cancer Society; National Brain Tumor Society

Call IndyStar staff reporter Shari Rudavsky at (317) 444-6354. Follow her on Facebook and on Twitter.