GOLDEN VALLEY, Minn -- Former President Jimmy Carter recently told the world he once thought he only had a few weeks to live. After his brain cancer diagnosis last year, things didn't look good. The former President decided to try an unconventional treatment, immunotherapy, and the results were nothing short of remarkable. President Carter has been cancer free for months.

Immunotherapy treatments are being used to treat more types of cancer every year, and thanks to its success, it is revolutionizing the way cancer is treated.

Dr. Thomas Amatruda has been using immunotherapy with his cancer patients. He joined us to explain what immunotherapy is, what types of cancer it is being used to treat and how it’s changing the way we fight cancer.

Q: What is immunotherapy?

Immune therapy is treatment of cancer by stimulating the immune system to fight cancer.

This has been a dream of cancer doctors and patients for many years. If the immune system could fight cancer, it could do it as effectively as the immune system fights an infection, targeting the cancer specifically.

Also, the immune system can keep fighting, even after the treatment stops, because the immune system remembers its targets. Think of how a measles vaccination protects you from measles for many years, maybe your whole life. That is because of the memory in the immune system.

Q: Is it used to treat all forms of cancer?

No. The immune checkpoint inhibitors are approved for use in melanoma, lung cancer, cancer of the mouth and throat, kidney cancer. There are some other cancers where it seems to work, and clinical trials are underway to see how well it works, and whether this is safe and effective.

It generally works best in cancers which have many mutations, since those cells look different to the immune system, compared with normal cells.

Q: Are certain patients better candidates for immunotherapy?

Yes. First, they have to have a cancer where it is likely that immune therapy would work. That may include some cancers in which the treatment is still under study.

Second, they can’t have diseases in which the immune system is already attacking the body. This is a very important point. The immune system can attack the body. That is the cause of diseases like rheumatoid arthritis, psoriasis, some other skin diseases, some kinds of liver disease, ulcerative colitis.

The main danger of immune therapy with immune checkpoint inhbitors is that the immune system can be stimulated to attack normal cells, not just the cancer, and that can make people sick. These immune side effects can be treated with prednisone or cortisone, but they can develop quickly and be hard to detect.

So, we use these always with caution, and particularly in people who already have some type of immune disease.

Q: Could this change the way we fight cancer?

It already has. In particular in melanoma, the cancer that I treat mostly, it has dramatically improved the remission rate in advanced melanoma. Patients who had advanced melanoma have had complete disappearance of disease, and have stayed free of disease for many years, 7-10 years and counting. This type of response was very rare before these treatments.

People always ask if these patients are cured. We don’t know, since the treatments have only been in use for 10 years, and some of the newer treatments less than 5 years.

Also, I think many oncologists are superstitious about using the word cure. We have all seen patients who had late relapses from their cancer. We can say that there are patients who are living free of their cancers, free of side effects of their treatment, and feeling well, many years after treatment.

Q: Should cancer patients be asking for this type of treatment?

They should talk to their cancer doctors. There are many cancers where this type of treatment can help, but not all cancers. In some of the other cancers, there are clinical trials using these new agents which may be valuable to patients.

We encourage patients to take part in clinical trials, since these experimental treatments can be more effective and safer than standard treatments. The way that we know if this is so is through clinical trials, and the way that we offer the new treatments is as a part of a trial.

Q. Are there any other significant developments in the treatment of cancers?

The major developments related to immune therapy are treatments which involve combinations of immune therapies. The combination of ipilimumab with nivolumab has turned out to be more effective than either alone, but at the cost of more toxicity. Several research trials are exploring how to best combine these new treatments.

We have been working with a virus which is injected into melanoma cells to kill the tumor and to activate the immune system. We have research trials giving these virus injections together with one of the immune checkpoint inhibitors.

An important development is the use of the new agents to prevent melanoma from coming back. Research trials are exploring this.

Also, there are new targeted therapies that work directly on the cancer cell to block its growth. These are exciting treatments because they can be very specific for the mutations that make the cancer cell grow.