What You Need to Know About Jimmy Carter's Cancer Diagnosis

— -- Former President Jimmy Carter announced this morning that he is battling metastatic melanoma, making him one of an estimated 74,000 Americans who will be diagnosed with melanoma this year, according to the National Institute of Health.

Seemingly calm and relaxed at a news conference at Emory University in Atlanta, Carter told reporters the cancer was first spotted on his liver in a scan and that further tests have revealed he has four additional tumors on his brain.

Doctors removed the tumor from his liver, taking out about 10 percent of the president's liver, but he will undergo radiation treatment and immunotherapy to target other tumors.

Carter said he expects that medical staff will likely find new tumors as treatment progresses. Experts say Carter’s diagnosis shines a light on rising melanoma rates but also highlights how new treatments are helping patients live longer.

While Carter, 90, had a strong family history of deadly pancreatic cancer, which took the life of his father and multiple siblings, experts said his diagnosis of melanoma instead of pancreatic is not surprising.

“From 1975 to present, there has been an increase in melanoma, especially in older white men,” Dr. Leonard Lichtenfeld, deputy chief medical officer for the American Cancer Society, said. “It’s not unique; it happens, unfortunately.”

He said it’s still unknown whether a family history of pancreatic cancer could have made Carter more susceptible to melanoma. Lichtenfeld said that while Carter’s diagnosis is serious, he has actually fared better than others with metastatic melanoma who can have large lesions on the liver or brain that greatly impair their lives.

Even at his age, experts said, Carter’s overall vibrancy and new treatments give him a far better chance at surviving longer than if he was diagnosed just a few years ago.

Immunotherapy drugs called “checkpoint inhibitors” have been used in recent years to help melanoma patients live longer. The drugs aim to get the immune system to fight the tumor directly.

Dr. Andrew Sloan, director of the Brain Tumor and Neuro-Oncology Center at University Hospitals Case Medical Center in Cleveland, said scientist have only recently understood how “tumors recruit the immune system.”

“Tumors have figured out how to turn off the immune system,” Sloan said. “They recruit cells that surround them … these are not cells that kill the tumor they protect cells from part of the immune system.”

New medications, including the drug pembroluzimab, with which Carter will be treated, aim to keep the immune system from turning off. Lichtenfeld said such therapies, first presented in 2010, were the first new drugs for melanoma since the 1970s.

“Five years ago,” Lictenfeld said, “we would not have much to offer the president.”