John McCain's Cancer Journey: Understanding Glioblastoma

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As we honor the life and legacy of Senator John McCain, who has died at age 81, we remember all those who have faced a brain cancer diagnosis with courage. Sen. McCain lived over a year with primary glioblastoma, an aggressive and persistent form of brain tumor. This devastating diagnosis often gives patients only a year or more to live, but ongoing research seeks to find new and better treatment options.

We consulted Dr. Herbert Newton, an AdventHealth neuro-oncologist and neurologist with 30 years of experience treating brain and spinal cord tumors, to better understand what makes glioblastoma so incredibly difficult.

Glioblastoma spreads quickly and has no cure yet.

Glial cells form the brains glue-like supportive tissue, and the most abundant glial cells in the brain are called astrocytes, named for their star-like shape. Astrocytes tile the central nervous system to help regulate the brains transmission of electrical impulses. They are closely connected to the brains dense network of blood vessels, which contributes to the aggressiveness of cancers that affect them.

Tumors arising from astrocytes are called astrocytomas, and glioblastomas are the most aggressive type, grade 4, explains Dr. Newton.

Glioblastomas are the most common malignant brain tumors found in adults over age 25, making up about two-thirds of astrocytomas, he adds.

And while glioblastomas are not common compared to other types of cancer, Dr. Newton says that as specialists in cancers that affect the brain, its a common cancer he and his team treat at the AdventHealth Cancer Institute.

Patients are beginning to travel to us for their glioblastoma treatment; we have seen up to three new cases a week, Dr. Newton notes. While we offer some of the latest treatments for glioblastoma, this cancer is very aggressive, and no treatment is a cure at this point in time.

Glioblastomas are often diagnosed after a quick onset of symptoms.

In July 2017, Sen. McCain got a CT scan after sharing symptoms of fatigue, mental fogginess and double vision with his doctor. When they detected a blood clot, they operated to remove it. But lab results from that surgery confirmed the presence of brain cancer associated with the blood clot.

Glioblastoma is typically a very fast-growing tumor, so symptoms tend to come on quickly and intensely and correlate to the part of the brain the glioblastoma is affecting, advises Dr. Newton.

He explained that a very common initial symptom is a fast onset of headaches that differ from your typical tension or migraine headache. Other symptoms can occur alone or in combination, and include:

  • Balance issues
  • Weakness on one side of the body
  • Changes in memory or cognitive abilities
  • Difficulties with speech or vocation
  • Blurred vision
  • Seizures

Patients generally come to the ER or their primary care physician with these symptoms, depending on how severe, and after diagnostic testing that includes an MRI, will get the formal diagnosis, advises Dr. Newton. He says blood clots like the one Sen. McCain experienced are a much rarer symptom of glioblastoma.

If glioblastoma is suspected, patients will then be referred to a neuro-oncologist like Dr. Newton for further evaluation and treatment recommendations.

Glioblastomas are difficult to treat effectively.

The worldwide standard of care for glioblastoma treatment includes a four-phase protocol, explains Dr. Newton.

  1. Maximal surgical resection (removal of the tumor)
  2. 6-week course of radiotherapy in combination with temozolomide chemotherapy
  3. Adjuvant chemotherapy with temozolomide for 6-12 months
  4. Use of Optune (low-intensity electric fields called Tumor-Treating Fields) in combination with adjuvant temozolomide

Dr. Newton described Optune as an FDA-approved glioblastoma treatment option offered to qualifying patients at the AdventHealth Cancer Institute. This unique cap-like device creates low-intensity electric fields that could help slow or stop glioblastoma cancer cells from dividing, and may also cause some cells to die.

Every patient's course of treatment is always customized considering a host of factors, including age, medical history, current health status and how well each patient tolerates treatments, which can become harder with advanced age.

And even for patients who do tolerate the treatments well, glioblastoma is often challenging to treat because of the tumors:

  • Heterogeneity (tumor cells that express and metastasize differently)
  • Possible location in a region of the brain that's difficult to access, or too close to major blood vessels or speech or motor strip of the brain
  • Tendency to reoccur rapidly and aggressively

Many of these challenges are being studied through clinical trials. Gaining a better understanding of why and how glioblastoma forms and progresses in the brain could lead to a cure.

There are clinical trials examining specific molecular therapies for glioblastomas that could bring more targeted treatments in the future, but this is still under study as a first line of treatment, says Dr. Newton.

The exact cause of glioblastomas is unknown.

If you have a relative with a glioblastoma, it doesn't necessarily mean you're destined for the same future.

Most glioblastomas are not inherited they usually occur sporadically in people with no family history of tumors, advises Dr. Newton.

They can rarely occur in people with certain genetic syndromes, but it's more likely to see some families having a strong predilection to cancer in general.

While there is no cure, there is still hope.

Organizations like the Glioblastoma Foundation work to raise awareness and fund research on molecular therapy for these extremely aggressive tumors. Physicians like Dr. Newton at the AdventHealth Cancer Institute join the fight by pushing the boundaries of medicine, studying and implementing some of the latest treatment options and surgical techniques to improve the care of patients with glioblastoma and other types of brain tumors.

Dr. Newton turned his fascination for the brain into helping patients find hope, even in the most serious circumstances.

I was always interested in the brain and how cancer affects the nervous system, which is what drove me to put these interests together with my career in neuro-oncology, he says. In our field, it is our hope to make an impact. And while we sometimes must provide sad or disappointing news, we always strive to extend and improve quality of life while providing comfort to patients and their families.

When a patient is diagnosed with a glioblastoma or other brain tumor, its a difficult journey, but one we walk along with them. You are never alone in your cancer treatment and you will always have our support in body, mind and spirit.

As clinical trials continue all across the country, we have hope that one day glioblastoma patients can look forward to better options and better outcomes.

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