How Immunotherapy Works
Immunotherapy is a type of cancer treatment that helps your immune system fight cancer. Unlike chemotherapy, which directly attacks cancer cells, immunotherapy works by enhancing, directing, or restoring your body's natural immune defenses.
Cancer cells often develop ways to hide from the immune system or suppress immune responses. Immunotherapy disrupts these mechanisms, allowing the immune system to recognize and destroy cancer cells.
Types of Immunotherapy
Checkpoint Inhibitors
Checkpoint inhibitors are the most widely used immunotherapy drugs. They block proteins that cancer cells use to "turn off" immune cells. Common examples include pembrolizumab (Keytruda), nivolumab (Opdivo), and atezolizumab (Tecentriq).
CAR-T Cell Therapy
CAR-T (chimeric antigen receptor T-cell) therapy involves removing T cells from a patient's blood, genetically engineering them to attack cancer, and infusing them back into the patient. It is used primarily for certain blood cancers.
Monoclonal Antibodies
These lab-made proteins mimic the immune system's ability to fight off harmful pathogens such as cancer cells.
Cancer Vaccines
These stimulate the immune system to attack cancer cells. The HPV vaccine prevents cervical cancer; other therapeutic vaccines are being studied.
Which Cancers Can Immunotherapy Treat?
Immunotherapy is approved for many cancer types including melanoma, lung cancer, bladder cancer, kidney cancer, head and neck cancer, colorectal cancer (with certain mutations), liver cancer, cervical cancer, and some lymphomas and leukemias.
Side Effects of Immunotherapy
Because immunotherapy activates the immune system broadly, it can cause inflammation in normal tissues — called immune-related adverse events (irAEs). Common side effects include fatigue, skin rash, diarrhea, and joint pain. More serious but less common side effects include inflammation of the lungs, liver, or colon. Report any new or worsening symptoms to your care team promptly.