For many cancer patients, the best treatment to help eradicate cancer cells is chemotherapy. Chemotherapy works to kill cancer cells, but in the process, it also damages healthy cells, leading to side effects that include nausea, fatigue, and hair loss. A different approach, called immunotherapy, is to boost the body's own immune system so that immune system cells seek out and destroy cancer cells.
How Does Immunotherapy Work?
There are a few different types of immunotherapy that oncologists are currently using. They all involve boosting the body's T-cells — those immune cells that specifically seek out and fight invading viruses and rogue cells — but they work in different ways.
- Checkpoint inhibitors are a type of drug that blocks cancer cells' ability to shut down the immune system. This frees up the T-cells to attack cancer cells. These drugs are given intravenously.
- Cell therapy is a process where the body's immune cells are removed, changed genetically so they can better fight cancer, then put back into the body. At the same time, more cells can be cloned or created so there are more T-cells circulating throughout the body.
- Bispecific antibodies grab both T-cells and cancer cells and bring them closer together so the T-cell can fight. They may work best with certain types of cancer, like leukemia.
- Vaccines give the body tiny amounts of cancer in a way that encourages the T-cells to attack. This works like childhood vaccines that introduce just enough of a weakened disease that the body learns to fight against it and develop an immune response. So far, vaccines have been used against prostate cancer.
How Effective is Immunotherapy?
Immunotherapy can work very well in some cancer patients, but there's no guarantee of success. Checkpoint inhibitors, which are currently the most widely used type of immunotherapy, successfully impact tumors in about 15 to 25 percent of cases. Some types of cancer — for example, bladder cancer — respond better to treatments.
The good news is that if immunotherapy works on a certain type of cancer or in certain situations, it does tend to work well. One study of cell therapy on children with leukemia found that 90 percent of patients went into complete remission.
Does Immunotherapy Have Side Effects?
Patients may have serious side effects from immunotherapy, because when the body's immune system is revved up so high, it can start to attack healthy areas. Sometimes this leads to inflammation and auto-immune responses like arthritis. In some cases, the immune system starts to attack the thyroid or pituitary glands. Doctors who work with immunotherapy are aware of these potential side effects and monitor patients closely. Typically, steroid drugs can reduce the issues, though they may also prevent the immune system from functioning at a very high level so that the immunotherapy is not as effective against cancer.
If you are evaluating or learning more about cancer treatments, talk to your oncologist about whether immunotherapy could work for your situation.