McCain’s rare type of cancer incurable
Glioblastoma digs into brain
The announcement of Sen. John McCain’s brain tumor diagnosis was met with an outpouring of support by well-wishers highlighting the Arizona Republican’s fighting spirit and fortitude.
Yet his type of tumor — a primary glioblastoma — is an entirely different adversary than any he has faced before.
“I greatly appreciate the outpouring of support — unfortunately for my sparring partners in Congress, I’ll be back soon, so stand-by!” Mr. McCain said Thursday in a tweet.
Of the 80,000 cases of brain tumors typically diagnosed each year, about 15 percent are glioblastomas, according to the American Brain Tumor Association.
The aggressive nature of the tumor and its amorphous shape — expanding and burying itself in the soft tissue of the brain — makes it difficult to remove with surgery.
The American Cancer Society estimates that more than 23,000 cases of malignant brain tumor will be diagnosed this year and that more men than women will be affected. The prognosis is dire: Patients with glioblastoma typically are given less than a year to live. With treatment, life expectancy grows to about 14 months to three years.
“Ten percent of people may survive five years or longer, but it’s not clear what individual characteristics may contribute to them surviving longer,” said Nicole Willmarth, chief science officer for the American Brain Tumor Association. “When treating patients, doctors will look at a number of factors — overall health, co-morbidities — one always has to weigh the risks and benefits of treatments.”
Mr. McCain’s tumor was discovered after he underwent surgery to remove a blood clot in his brain. In a statement released Wednesday, the Mayo Clinic in Arizona confirmed that the clot was associated with a glioblastoma and that the senator underwent further surgery to remove cancerous tissue. Mr. McCain, his family and his doctors are considering further treatment, including chemotherapy and radiation.
Glioblastomas usually are discovered when the brain tumor gets to a size that it impairs a person’s functioning. A patient will report symptoms including headache, nausea, vomiting and drowsiness. It also can create changes in personality, memory loss, difficulty with speech, changes in vision, seizures and weakness on one side of the body — depending on where the tumor takes hold.
The senator’s cancer announcement shed new light on his performance last month during a Senate hearing with former FBI Director James B. Comey. Mr. McCain was uncharacteristically incoherent and rambling during his questioning of Mr. Comey. He later blamed his fatigue on staying up late watching a baseball game the night before.
Mr. McCain’s former Democratic colleague, Sen. Edward M. Kennedy, succumbed to glioblastoma in 2009, as did Beau Biden, a son of former Vice President Joseph R. Biden, in 2105.
There is no known cause for glioblastoma, and researchers have not linked its occurrence to a family history of cancer or tumors. Certain genetic syndromes are linked to glioblastomas, although these cases are rare.
The tumor is known to develop from rogue astrocytes, star-shaped cells essential to the functioning of the brain and central nervous system. There are five grades of astrocytomas — tumors from astrocytes — and about 60 percent are glioblastomas, which are classified as either primary or secondary.
Mr. McCain’s diagnosis is primary glioblastoma, the most common type in older people. Mr. McCain is 80. Secondary glioblastoma tumors most frequently appear in people younger than 45 and develop at a slower pace than primary glioblastoma tumors. Secondary tumors represent about 10 percent of glioblastomas, according to the American Brain Tumor Association.
Surgery is the first course of action, but the tumor’s tentaclelike reach into the crevices of the brain make it difficult for surgeons to excise all parts of the tumor.
After surgery, patients typically are prescribed oral chemotherapy in conjunction with radiation. This is the standard of care, but clinical trials and research continue to push the boundaries of treating this disease.
Because glioblastoma is such a rare form of brain cancer, the Food and Drug Administration considers research and development for treatments to be “orphan drugs.” Congress has enacted legislation to give pharmaceutical companies incentives to develop treatments for such rare diseases and conditions.
Scientists have been researching identification of certain biomarkers — the occurrence of specific molecules in the body — that could indicate how a person is expected to respond to chemotherapy.
“There are patients with a certain marker that tend to benefit more from chemo — that would be a factor to consider when determining what treatments to give individual patients,” Ms. Willmarth said.
In 2015, the FDA approved a treatment using a head cap called Optune that sends electric currents into the brain to disrupt cancer cells from dividing, halting the growth of the tumor.
In clinical studies, the tumor stopped growing for at least seven months for patients wearing the Optune cap while on oral chemotherapy treatment. For those only on oral chemotherapy drugs, tumors were held at bay for at least four months.
This article is based in part on wire service reports.