The short answer
Senator John McCain was diagnosed with glioblastoma, an aggressive brain cancer, in July 2017 after doctors removed what appeared to be a blood clot above his eye and found the tumor. He had surgery, radiation, and chemotherapy, kept working, and died on August 25, 2018, at age 81, a day after choosing to stop treatment.
John McCain was diagnosed with glioblastoma in July 2017, at age 80.
The tumor was found after surgery to remove what looked like a blood clot above his left eye.
He was treated with surgery, radiation, and chemotherapy and continued to serve in the Senate.
Glioblastoma is the most common and most aggressive form of primary brain cancer in adults.
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The full explanation.
Who he was
John McCain was a United States Senator from Arizona, a former prisoner of war, and a two-time presidential candidate whose long public life made him one of the most recognizable figures in American politics. In the summer of 2017, McCain became a public face of a very different kind of fight — one against glioblastoma, the aggressive brain cancer that also claimed his friend and Senate colleague Ted Kennedy years earlier.
The diagnosis
McCain's cancer was discovered almost by accident. In July 2017, doctors at the Mayo Clinic in Arizona performed surgery to remove what appeared to be a blood clot above his left eye. When the tissue was examined, it turned out to be associated with glioblastoma. He was 80 years old.
Glioblastoma is the most common and most aggressive primary brain cancer in adults — a tumor that starts in the brain and grows quickly. Scans after surgery indicated the visible tumor had been removed, and McCain went on to receive the standard follow-up treatment.
The story
After surgery, McCain underwent radiation therapy and chemotherapy, the usual approach for glioblastoma. Characteristically, he kept working. He returned to the Senate during his treatment and remained engaged in his duties, including a dramatic vote that drew national attention, even as he managed the demands of therapy.
Over the following year, the disease progressed. On August 24, 2018, his family announced that he had decided to stop active treatment. He died the next day, August 25, 2018, at age 81 — a little over a year after his diagnosis. His death, like Kennedy's, brought national attention to how difficult glioblastoma is to treat.
What his story teaches
John McCain's story is a clear, if sobering, introduction to brain tumors and specifically to glioblastoma. Unlike many cancers, glioblastoma is a primary brain tumor — it starts in the brain rather than spreading there from elsewhere. Its symptoms depend on where it grows and can include headaches, seizures, vision changes, or new problems with thinking or coordination; you can read more about brain tumor symptoms and how these tumors are found.
His case also shows the realities of brain tumor treatment. The standard approach — surgery to remove as much tumor as possible, followed by radiation and chemotherapy — can extend life and preserve function for a time, but glioblastoma remains very hard to cure and tends to return. McCain's decision to keep working through treatment, and later to stop it on his own terms, reflects deeply personal choices that many patients and families face. His willingness to be public about his diagnosis helped raise awareness of a cancer that badly needs better treatments.
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The bottom line
John McCain was diagnosed with glioblastoma in 2017 after surgery revealed the tumor, treated it with radiation and chemotherapy while continuing to serve, and died about a year later at age 81. His story is a plain-language lesson in the most aggressive adult brain cancer — how it is found, how it is treated, and why it remains one of medicine's toughest challenges.
This article summarizes publicly reported information; details may evolve. Spotted an error? Please email [email protected].
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Common questions
▸What kind of cancer did John McCain have?
He had glioblastoma, an aggressive cancer that starts in the brain. It was diagnosed in July 2017 after surgery at the Mayo Clinic to remove what appeared to be a blood clot above his left eye; testing of that tissue revealed the tumor.
▸How was it treated?
Scans indicated the visible tumor had been removed during surgery, and he then received standard treatment for glioblastoma: radiation therapy and chemotherapy. Despite this, glioblastoma is very difficult to cure and tends to return.
▸What is glioblastoma?
Glioblastoma is the most common and most aggressive primary brain cancer in adults — meaning it starts in the brain rather than spreading there from elsewhere. It grows quickly, and even with surgery, radiation, and chemotherapy, it is currently considered very hard to cure. Survival varies from person to person.
▸How long did he live after diagnosis?
About 13 months. He was diagnosed in July 2017 and died on August 25, 2018, at age 81. His family announced the day before his death that he had decided to stop active treatment.
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