The promise of cancer immunotherapy has grown in recent years with the advent of new drugs and treatments that allow the body’s immune system to fight cancer.
In this video, Michael Kosty, MD, a medical oncologist at Scripps Clinic, joins host Susan Taylor to discuss the evolution of cancer immunotherapy and the increasing role it is playing in the treatment of many forms of cancer.
“This is really an exciting time,” says Dr. Kosty, who is also medical director of the Scripps Green Cancer Center. “The pace of change has been great.”
Immunotherapy uses the natural power of the immune system to fight cancer. There are different types of immunotherapy treatments, including vaccines and antibody therapies. Some stimulate the body’s immune system to help fight the disease. Others help train the immune system to specifically attack cancer cells.
While the immune system is the body’s defense against infection and illness, there are limits on its ability to fight cancer on its own. Sometimes the immune system recognizes the cancer cells, but fails to respond strongly enough to destroy the cancer. Other times the immune system doesn’t recognize the cancer cells as foreign.
“Many cancers have proteins on their surface that act like camouflage to the body’s immune system,” Dr. Kosty says. “What the immunotherapies do is basically strip away the camouflage and allow your body’s immune system to then attack the cancer that shouldn’t be there.”
Patients usually receive treatment every other week or every third week. Each treatment takes about an hour. Typically, it takes two to four months for an immune response to develop. A patient may continue on the therapy anywhere from a year to an indefinite period, with the average being about two years, Dr. Kosty says.
The main side effect of immunotherapy is fatigue. Other side effects that are less common include diarrhea, skin rash and low thyroid function.
With the exception of breast cancer and prostate cancer, immunotherapy has shown significant promise in treating many cancers.
“There’s been either a small, or in some cases, a really large improvement in survival in patients with advanced disease,” Dr. Kosty says.
Depending on the situation, immunotherapy is used alone or in conjunction with chemotherapy or radiation.
“Increasingly we are finding that for patients to get the most durable, longest lasting benefit, immunotherapy needs to be combined with something else,” Dr. Kosty says. “With lung cancer, for example, we would combine immunotherapy with chemotherapy.”
Adding immunotherapy to a cancer treatment “often allows us to reduce the dosage of the chemotherapy that we would use otherwise, or shorten the number of radiation treatments that would be required,” Dr. Kosty says. “The net effect is the side effects are more favorable, less toxic to the patients in general.”
Determining who is a good candidate for immunotherapy depends on several factors, according to Dr. Kosty.
“You need to know if the tumor is in an early or advanced stage. If it’s early, there are probably curative strategies like surgery or radiation therapy to completely eradicate the tumor, and immunotherapy would not be appropriate,” he says.
“If the tumor is more advanced, there are tests that can be done on the tumor looking for those camouflaged proteins,” Dr. Kosty says.
While immunotherapy has been around for decades, research and development of new drugs have taken off in recent years, which bodes well for the fight against cancer.
“While significant advances have taken place, the immunotherapies that we have available now are actually pretty rudimentary,” Dr. Kosty says. “As we look down the road, not too far, three, four years, there will be different types of immunotherapies; there will be different things that are combined with existing immunotherapies that will result in patients doing better, living longer and having fewer side effects from their treatment, which is a win, win, win.”