Former President Jimmy Carter announced on Sunday that his cancer is gone. According to a statement from the Carter Center, his "most recent MRI brain scan did not reveal any signs of the original cancer spots nor any new ones."
Carter first revealed in August that he had been diagnosed with melanoma, and that a surgery to remove a mass from his liver showed that the illness had spread to his brain.
But what, exactly, does being "cancer-free" mean in this context? For starters, 91-year-old Carter is not "cured" of the disease. That term that generally refers to being cancer-free for at least five years.
"Terminology is important in this case," Dr. Yusuf Hannun, director of the Stony Brook University Cancer Center, told The Huffington Post. "Cancer-free means there is not detectable cancer -- that's often what physicians would call 'complete remission of the disease.'"
Remission in and of itself is "a really highly desirable goal," Hannun said, because it's a step towards being cured. In other words, Carter's complete remission is not the same as being cured. It's merely a prerequisite for a cure.
According to the New York Times, doctors used strong but targeted stereotactic radiation therapy to treat the four tiny lesions in Carter's brain. The former president is also being treated with an expensive immune system-boosting melanoma drug called pembrolizumab, or Keytruda, which costs $150,000 per year, USA Today reports.
"People who respond to drugs like Keytruda tend to respond for a while," Timothy Turnham, executive director of the Melanoma Research Foundation, told USA Today. "There is every likelihood that when he dies, it will be from something other than melanoma."
Most cases of melanoma begin as skin cancer, but in Carter's case, doctors haven't determined where his cancer originated. If caught early, melanoma is largely curable, but when it spreads throughout the body, it can be deadly. According to the American Cancer Society, about 74,000 new cases of melanoma will be diagnosed in the U.S. this year, and about 10,0000 people are expected to die from the disease.
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