Your immune system does more than simply fight colds and flu. Throughout your life, your natural defenses seek out and destroy anything that is not recognized as part of the “self” — including all kinds of germs and cancer cells — before they have a chance to cause disease. Your immune system manages to destroy most rogue cells before they form a full-fledged tumor, but some of them get by your defenses. If you already have cancer, your immune system will still be working hard to keep your disease in check, but it probably can’t do the job on its own.
In recent years, more and more cancer patients have received treatments designed to give the immune system the upper hand against cancer. This approach — called immunotherapy or biological therapy — isn’t as widely used as radiation or chemotherapy. For most types of cancer, immunotherapy hasn’t been shown to be more effective than these standard treatments. And like the others, it can cause its own unpleasant side effects.
But immunotherapy can still be a powerful tool, either on its own or combined with chemotherapy or radiation. For certain patients — immunotherapy can offer more than the conventional options, even the possibility of a complete cure. For others, it’s an additional, less toxic method of controlling their disease or reducing side effects from other treatments. In the years to come, as scientists learn more about the immune system, immunotherapy promises to become even more common and more effective.
Is it safe? What does it involve?
Immunotherapy often involves adding more immune cells, immune signaling molecules, or other biochemicals to the body. Unlike chemotherapy, which affects all fast-growing cells, immune treatments target specific processes or types of cells and should have a low impact on healthy tissues. The side effects depend on the particular biological agent used. Some have very mild side effects, while others cause serious problems.
The delivery will also depend on the agent used as well as your treatment plan. Some immunotherapy treatments are in the form of pills or shots you can take at home, while others are delivered intravenously (IV) in the hospital or clinic. Immunotherapy may be administered a couple of times a day or as seldom as every month or two.
What are the different types of immunotherapy?
There are two major types of immunotherapy: Treatments that add new disease-fighting cells to your body (T cells) and treatments that add other elements to your own immune system (such as antibodies, cytokines, and others). Many immunotherapy agents are experimental or investigational and are only available by enrolling in clinical trials.
Here’s a brief look at some common therapies:
T cells. T cells are a type of immune cell that can recognize and destroy problem cells, either indirectly (helper T cells) or directly (killer T cells, also called cytotoxic T lymphocytes or CTLs). In some cancer patients, there are CTLs that can recognize tumor cells.
T cell therapy is an approach that works by boosting this natural immune response — taking these cells out, making more of them in the lab, and putting them back in the patient. Usually, in combination with other therapies, T cell therapy can sometimes shrink tumors such as melanomas. Side effects can include fever and chills.
Monoclonal antibodies. The B cells in your immune system produce antibodies against bacteria, viruses, toxins, and other cells that they don’t recognize as part of your own body. (Regular vaccines work by stimulating your immune cells to produce antibodies, so they are available in case they are needed in the future.)
In this form of immunotherapy, patients receive large intravenous doses of monoclonal antibodies, which are produced in the laboratory. The term monoclonal simply means that all of the cells are exact copies of one another and are derived from a single cell.
Each type of monoclonal antibody is designed to attack a specific target. For example, patients with certain types of lung cancer, colon cancer, and breast cancer can be treated with