Remembering John McCain and Understanding Glioblastoma

Found while looking for something else

In July 2017, surgeons removed a blood clot from above Senator John McCain's left eye. Laboratory work on the tissue they took out revealed a glioblastoma, and the Mayo Clinic confirmed the finding in a public statement. NPR reported at the time that the tumor sat just behind his forehead, on the left side of the brain.

He kept working and speaking publicly for the next year. On August 24, 2018, his family announced that "with his usual strength of will, he has now chosen to discontinue medical treatment." He died the following day at the age of 81.

That is the disclosed record. This article does not go further into his care, and it draws no lesson from his decisions. The medicine below is the point.

What kind of tumor this is

Glioblastoma is a malignant tumor that starts in the supporting cells of the brain rather than in nerve cells themselves. The World Health Organization ranks brain tumors by grade, from I to IV, and glioblastoma is grade IV, the fastest-growing category.

The National Cancer Institute is blunt about the difficulty: cure rates with standard treatment are very low. Part of the reason is anatomy. The tumor does not sit as a tidy ball that a surgeon can lift out. It spreads microscopic extensions into surrounding brain, so tumor cells remain after even a thorough operation.

David Arons, chief executive of the National Brain Tumor Society, described it to STAT as "one of the most complex, drug-resistant, and adaptive cancers there is."

How it usually announces itself

McCain's tumor came to light during a procedure for something else, which happens. More often, symptoms come first. NCI and MedlinePlus list these:

• Headaches, often worst in the morning, sometimes easing after vomiting.
• Seizures.
• Trouble with speech, hearing, or vision.
• Nausea, vomiting, and loss of appetite.
• Weakness, poor balance, or difficulty walking.
• Changes in thinking, memory, mood, or personality.
• Unusual sleepiness or fatigue.

Much of this comes not from the tumor itself but from swelling in the brain tissue around it, which doctors call peritumoral edema. The skull cannot expand, so pressure builds and function suffers.

When to get checked

Some findings need attention the same day. Go to an emergency department for:

• A first seizure, at any age.
• Sudden weakness, numbness, or drooping on one side of the body.
• Slurred speech, or sudden trouble finding words.
• A headache that reaches maximum intensity within a minute of starting.
• New confusion, or a sharp change in behavior that others around you notice.

Arrange a prompt appointment, within days rather than months, for a headache that is new for you and has been worsening steadily for more than two weeks, especially if it is worst on waking or comes with vomiting. The same goes for a new blind spot, new double vision, or persistent unsteadiness.

There is no screening test to catch this early. NCI says outright that it has no evidence-based information about preventing brain tumors and none about screening for them. Nothing in a routine physical looks for a glioblastoma, so symptoms are the only entry point.

The workup

MRI with a gadolinium contrast agent is the main imaging test, and CT or PET scans may be added. Scans narrow the possibilities but cannot make the diagnosis on their own.

Tissue settles it. A stereotactic biopsy uses computer guidance to sample a deep tumor through a small opening, while a craniotomy opens the skull for direct access. The laboratory then examines the cells and runs molecular tests, including the IDH gene.

What treatment aims to do

Standard care combines three things. Surgery removes as much tumor as is safely possible. Radiation follows, delivered as 60 Gy in 30 daily fractions across six weeks, given alongside the oral chemotherapy drug temozolomide. Further cycles of temozolomide follow, up to six.

Supportive medicines run in parallel and matter a great deal to daily life. NCI notes that dexamethasone, mannitol, and furosemide are used to reduce swelling around the tumor, and that anticonvulsants are mandatory for anyone who has had a seizure.

The goal of all this is control and time, not cure. Being clear about that up front is not pessimism, it is what the evidence supports.

What shapes the outlook

Several factors weigh on prognosis, and two are worth naming.

Age is one. Dr. Nader Sanai told NPR that "the older you are, the worse your prognosis is," partly because older patients tolerate aggressive therapy less well. McCain was 80 at diagnosis. Performance status is another, and NCI lists a WHO performance score of 1 or higher, meaning any limitation in normal activity, among the poor prognostic signs.

Molecular findings count too. NCI reports that patients with IDH wild-type tumors, the large majority, had the worst prognosis regardless of treatment type.

For context, the American Cancer Society projected 24,740 new cases and 18,350 deaths from brain and other nervous system cancers in the United States in 2026, and SEER, the federal cancer statistics program, carries that projection. SEER's own measurement of five-year relative survival across that whole mixed group is about 33 percent, and glioblastoma sits far below that average. These are population figures. They summarize what happened to many people over past years, and they do not tell any individual what lies ahead.

Where the research actually stands

Progress has been real but small. NCI reports that adding the drug bevacizumab to radiation and temozolomide did not improve overall survival in newly diagnosed disease. For tumors that come back after radiation, NCI notes that no randomized trials define the role of a second course of radiation.

That is why clinical trials feature so heavily in glioblastoma care, and why the field keeps returning to the same conclusion: the treatments that will change these numbers do not exist yet.

Sources

• https://www.cancer.gov/types/brain/hp/adult-brain-treatment-pdq
• https://www.cancer.gov/types/brain/patient/adult-brain-treatment-pdq
• https://seer.cancer.gov/statfacts/html/brain.html
• https://medlineplus.gov/braintumors.html
• https://www.npr.org/sections/health-shots/2017/07/20/538295015/john-mccain-was-diagnosed-with-a-glioblastoma-among-the-deadliest-of-cancers
• https://www.cbsnews.com/news/john-mccain-brain-cancer-medical-treament-discontinue-family-says-2018-08-24/
• https://www.statnews.com/2018/08/25/mccain-glioblastoma-research/