John McCain died of a form of brain tumor called glioblastoma – an extremely complex malignant tumor that is difficult to treat and curable for the time being.
Glioblastoma affects the glial cells, the sticky supporting membranes that surround the glioblastoma brain nerve cells and affects about 200,000 Americans each year. Senator Ted Kennedy died of it nine years ago.
It differs from other types of brain tumors by its rapidity and malignancy.
"There are many types of brain tumors," said Alfred Yung, a professor at the University of Washington MD Anderson Cancer Center of the University of Texas and a researcher working with the National Cancer Institute. "They range from very slow-growing, benign brain tumors that are unlikely to kill the patient very quickly to those of glial cells."
Two things make glioblastoma especially difficult to treat. First, the researchers have no idea why glial cells become cancerous. Theories range from genetics to environmental risk factors to a combination of the two. The second is the location of the cancer, which is so deep in the brain that it is almost impossible to cleanly separate the tumor from the sensitive organ.
"The tumor is very complex," said Yung. "It's a mix of different types of cancer cells and different behaviors."
But research is growing. Former Vice President Joe Biden is focusing his efforts on the White House to lead the Biden Cancer Initiative after his son Beau died from a recurrence of brain tumors (not glioblastomas). He consoled McCain's daughter last December and highlighted the progress made in the field of brain tumors.
Gordon Li, a neurosurgeon at Stanford University specializing in brain tumors, says that the glioblastoma is incurable because it can multiply and take over the organ that is central to whole-body surgery, and the difficulty of To detect and remove cancer cells and tumors.
Because of the dense folds of the brain, even a slight ringing by laser or radiation can be dangerous. And even if a tunnel is removed, the cancer almost always returns.
"Glioblastoma has micro-tumor cells that go through the brain … everywhere," Li told the Daily Beast. "Taking out only part of the brain makes no sense."
With survival rates of less than five percent, researchers are eager to find out what makes a person's glial cells cancerous. "We could diagnose it earlier, so we could take out [the cancer] [earlier] or we could work on agents to better see the tumor," Li said.
Oncologists and researchers have tried a variety of methods to delay death , The complexity of glioblastoma requires a combination of drugs and therapies that are needed to treat the patient. "If you use several things, you will probably cause side effects," said Yung. "And we still do not understand the biology and genetics of the tumor well, we still do not know enough about glioblastoma to know how many medicines to use and what kind of medicines and how much radiation to use." [1
Immunotherapy is another area of research, but glial cells do not have many T cells, which is a hurdle. The use of antibodies and gene therapy to change how these cells work is one possibility, but research is at an early stage.
Li experimented with dyes to follow the tumor and its cancer pathway. He also looks at the physics of these dyes in the brain to find out exactly which brain tissue the "more defined" cancer could go to next.
"There are some new imaging modalities in which we use different MRI [magnetic resonance imaging] and different radiographic tracers to track the vast majority of the tumor," he said. This could help doctors start radiation and chemotherapy earlier.
As techniques improve, Li and Yung said glioblastoma statistics remain grim. "The average survival rate is between 1.5 and two years," Li said. "There are patients who will live longer, there will be patients who do not live that long." McCain lived less than a year after his diagnosis had been publicly announced.
Variable survival time is a sign of differences in glial cell work. Engaging with it could expose genetic markers and lead to better treatments, Li said.
"Do not get me wrong, it's a bad cancer," Li said. "But in the past 15 years, we've got much more about that Understood biology and we have a lot of hope. "