President Jimmy Carter, the oldest living US president, announced in August 2015 that his melanoma had metastasized to his brain and liver — a very serious diagnosis for anyone, let alone a 91-year-old.
But by December, his doctors were unable to find any signs of the disease.
How was this possible?
Carter's recovery was likely due, at least in part, to a relatively new kind of therapy. Immunotherapy, as the treatment is known, uses the patient's own immune system to fight cancer cells.
Carter received a medication called Keytruda, which helps the immune system recognize and target cancer cells as if they were an infection — like, say, a bacteria or virus.
Because immunotherapy was done in conjunction with other treatments — namely, radiation therapy and surgery — it's hard to know exactly what to credit for Carter's remission. And even if it was the Keytruda, that doesn't mean the drug will help all cancer patients.
"What works for one patient might not help another," Green notes. "So medical professional usually combine treatments."
Indeed, previous research found that about 1 in 3 melanoma patients responded to the Keytruda. Of those, 82 percent saw a reduction in tumors, while 18 percent saw them reach undetectable levels like Carter did. Figuring out why some patients respond to Keytruda while others don't is key to developing similar medications that could save more lives.
It's also important to remember that while immunotherapy may have brought President Carter's cancer into remission, that doesn't mean the cancer has been completely eliminated from his body, only that there are too few cancer cells to detect. If any lurking cells continue to grow and spread, Carter will need more treatment.
Nonetheless, the results are extremely encouraging and suggest that we are on our way toward developing a powerful new weapon against cancer.
Cover image: Nir Levy / Shutterstock.com