Jimmy Carter is 'cancer free': Miracle or just science?

Jimmy Carter: I'm free of cancer
Jimmy Carter: I'm free of cancer

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Story highlights

  • Jimmy Carter tells a Sunday School class he leads that he is now cancer-free
  • Carter's announcement comes four months after he revealed that cancer had spread to his brain
  • A combination of surgery, radiation and immunotherapy was used to treat Carter

Atlanta (CNN)Jimmy Carter was teaching his regular Sunday school class at Maranatha Baptist Church in Plains, Georgia, when he broke the news: He is cancer free. The class broke into applause.

The former President announced in August that a deadly form of skin cancer, melanoma, which was first found in his liver, had spread to his brain. He was treated via surgery, radiation and a relatively new form of immunotherapy.
    On Sunday, Carter said in a statement: "My most recent MRI brain scan did not reveal any signs of the original cancer spots nor any new ones. I will continue to receive regular three-week immunotherapy treatments of pembrolizumab."
    CNN interviewed Dr. Leonard Lichtenfeld, deputy chief medical officer for the American Cancer Society, about Carter's announcement. Lichtenfeld has been following the former President's cancer treatment journey since it was first announced in August:

    A medical miracle?

    "Metastatic melanoma is a serious and potentially life-threatening illness. Whether we can call it a miracle or not, it will take time to tell. It's the best news possible in a difficult situation.
    "Right from very beginning, I had a good feeling about the President's prognosis. First, they were able to get control of the visible lesions. There weren't many lesions scattered all over the body, and they were able to treat the lesions they had with radiation and surgery. That puts the President into a better prognostic category than many other patients who have metastatic melanoma.
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    "The President obviously had awareness of [the] situation of several months before he had the surgery. I think it was in May he was having problems, and he had the surgery in August. That already suggests that this may have been more slowly developing. So that also puts him into better prognostic group than many others.
    "He also had a liver lesion that could be completely resected; they were able to take that portion out, and there were no other lesions in the liver or visible in the abdomen at that time. And during the workup they found four very small lesions on the brain, about 2 milliliters in size, and that is extremely small. Even the ability to detect such small lesions is a reflection on the technology we have today that we did not have several years ago. So the doctors were able to say we can surgically remove the liver, and radiate the brain, and we see no additional lesions at this time.
    "All of those are factors that suggested at that time the outcome for the President may be better than it would be for other patients with metastatic melanoma. By adding the immunotherapy to that, it may have also helped the situation.
    "Now, having said that, and this is important, we never know in a circumstance like this what tomorrow may bring. So in a situation like the President's, we're grateful for what we have today. For every patient, our hope and prayer is that this progress continues for many months and even years given these new treatments, but we don't know what the course of the disease is going to be. Right now, it's excellent, the best possible outcome, but every day is a new day."

    Immunotherapy drugs for melanoma

    "The drug President Carter is getting [pembrolizumab], is one of a group of drugs called 'check point inhibitors.' What happens is that the melanoma cells shut down the immune cells' ability to respond. These drugs interfere with that process, so, by interfering with that shutdown process, they allow the immune system to do its job.
    "Pembrolizumab is not the only one out there; we have worked for decades on developing drugs to help the immune system. There are several drugs that are approved, with more in the pipeline. When tried in the most advanced cases, which is where we always start with new drugs, the response rates for patients are somewhere between 35% and 40%. The duration of that response can vary from person to person, but some people have done well with these drugs for a long period of time.
    "We don't know how long these drugs will be effective, in the sense that the studies are so new that there are still patients on these drugs for several years, with a stable disease or disease that has gone into remission and has not recurred. And that was when drugs were used in most advanced cases.
    "Those drugs are now beginning to move up to earlier treatment in advanced melanoma, so that patients like President Carter are receiving these drugs in what we would call 'first line treatment.' And one of the advantages is that they have fewer side effects than more traditional forms of treatment, and when someone is in their 90s like President Carter is, and who is in reasonably good physical and mental health, these drugs become a very reasonable alternative to use."

    Side effects of immunotherapy treatment

    "There can be fever, diarrhea, malaise (and) appetite issues, but they are usually mild. One of the interesting things about these drugs is that as they wake up the immune system. There are certain organs or glands in the immune system that can, in a sense, 'turn on' the body and cause inflammation, but most patients don't have that problem and frankly it sounds like the President has done extremely well on this drug. There are some patients who don't have any side effects at all.
    "The President is fortunate that he is in good physical and mental health for his age. He has taken excellent care of himself. He's a physically and mentally active individual who's in the best health possible for someone in his age group. That's the result of decades of lifestyle choices and taking good care of himself."

    What's the future hold?

    "There's always the suspicion there are other small lesions and cancer cells. But it's possible that these immunotherapy drugs may keep those in check. In fact, with the type of drug President Carter is getting, pembrolizumab, in other patients ... they see the progression of the disease stopped.
    "There may be small nests of cancer cells that they can't find, so it's not possible to say President Carter has no cancer cells anywhere. But it's also possible that this drug may have awakened his immune system and destroyed other cancer cells in his body. We just don't know. What we do know is that he had this tumor seven months ago, and in the past we would have expected to see progression of cancer in a rapid fashion, but his disease is extremely well controlled if not completely treated. So, as I said earlier, this is absolutely the best news possible."