The family of Sen. John McCain announced Friday the Arizona Republican is discontinuing medical treatment for an aggressive brain tumor diagnosed a little over a year ago. While the senator has surpassed expectations for his survival, the family said in a statement, “the progress of the disease and the inexorable advance of age render their verdict.” Here is a closer look at what that decision means.

How often do patients end medical treatment for glioblastoma?

The prognosis for the disease is so poor — the median survival time is just 18 months — that most patients and their families eventually face the difficult decision of when to end treatment, said John de Groot, a neuro-oncologist at MD Anderson Cancer Center.

“At some point, all existing therapies have been tried, and sometimes experimental ones have been tried, and despite that, the tumor continues to grow,” he said. “The tumor burden becomes so great that doing anything additional becomes futile.”

Sometimes patients are too sick to make the decision themselves and rely on family members to decide when treatment should be discontinued, he said.

“Sometimes the patients themselves are very much capable of saying to their medical team, I have been through 10 different treatments, and I recognize the tumor is still growing and I’m okay with not continuing treatment,” he said. “And other times they want to fight, fight, fight and they aren’t able to make decisions for themselves, and then their families are driving the medical decisions.” 

How long do patients survive after making such a decision?

It varies, depending on the stage of disease and condition of the patient. “If tumor growth is rapidly progressing, it can be two to four weeks, or sometimes four to six weeks,” said de Groot, who has not been involved in McCain’s treatment.

Other experts agreed, saying patients typically survive weeks, or perhaps a few months, after declining treatment. Some patients die much more quickly.

How do patients decide when to end treatment?

Forgoing medical treatment is a deeply personal decision that is influenced not only by the course of the disease but also by quality of life — depending on the location of the tumor, a patient can lose the ability to speak, walk and see — and whether the treatment is helping or hurting.

“The decision has to do with the extent of the side effects, patients' personal outlook on life, what they value,” said Viviane Tabar, chair of neurosurgery at Memorial Sloan Kettering Cancer Center. “Some of the treatments are harsh, or require a patient to come to a medical center regularly, which can become burdensome.”

“The question is, are we helping you or hurting you?” said Deepa Subramaniam, director of the brain tumor program at Georgetown Lombardi Comprehensive Cancer Center. “Are we increasing suffering? Hastening your death? There are studies that have shown that continuing treatment with a patient who is frail and ill may actually hasten the process of dying.”

Typically patients receive hospice services at home after discontinuing treatment. And while they no longer get therapies to battle the tumor, they are given other drugs as needed, including pain and anti-seizure medication.

What is glioblastoma, and why is it so hard to treat?

Glioblastoma is one of the most lethal cancers, with a five-year survival rate of 5.1 percent. It is the most common malignant brain tumor in adults and arises from the star-shaped cells that make up the supportive tissue of the brain. More than 12,000 people in the United States will be diagnosed with glioblastoma this year, according to the National Brain Tumor Society.

The low survival reflects the lack of effective therapies. Patients typically undergo surgery, chemotherapy and radiation and sometimes receive drugs targeted to specific tumor mutations. But the cancer almost always comes back.

Between 1998 and 2014, 78 brain tumor drugs entered clinical trials and 75 failed, according to the National Brain Tumor Society. The challenges of developing treatments are myriad and  include getting medications into the brain, which is protected by the blood-brain barrier, a network of tissue and blood vessels that blocks most compounds.

Scientists have been testing immune therapy, which marshals the immune system to attack cancer, for glioblastoma. But it is far from clear the approach will work.

As researchers continue to hunt for better treatments, Tabar said, they have come to realize glioblastoma has several subtypes; it is not a single disease. “We're unlikely to come up with a single magic bullet,” she added.

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