Immunotherapies are a category of cancer drugs that work by helping the body’s immune system identify and destroy cancer cells. Immunotherapy has been called the “fourth pillar” of cancer treatment—the first three pillars being surgery, radiation therapy and chemotherapy. Immunotherapies are also sometimes called biologic therapies.
There are immunotherapies available for numerous different types of cancer, including several immunotherapy drugs that can be used in the treatment of non-small cell lung carcinomas. Non-small cell carcinomas are the most common type of lung cancer, and account for an estimated 80 to 85 percent of all cases of the disease.
Immune checkpoint inhibitors
Different immunotherapy drugs work in different ways. The type of immunotherapy drugs available for certain types of non-small cell lung cancers are called immune checkpoint inhibitors.
Immune checkpoints are pathways that prevent the immune system from attacking and destroying the body’s healthy tissues. Some cancers are able to use these pathways to prevent an attack from the immune system—they disguise themselves as healthy tissue so the immune system leaves them alone. Immune checkpoint inhibitors work by disabling this disguise, allowing the immune system to recognize and attack the cancer cells.
More specifically: the immune checkpoint inhibitors approved to treat certain types of non-small cell lung cancer target a protein called PD-L1, or a related protein called PD-1.
PD-1 is a protein found on T cells, a type of white blood cell that attack infections and cancer. When PD-1 encounters a cell with PD-L1, the two proteins bind together, and prevent the T cell from attacking—which is what prevents T cells from damaging healthy tissue, but also prevents T cells from attacking cancerous cells that are PD-L1 positive.
When an immune checkpoint inhibitor disables the function of either PD-L1 or PD-1, T cells are able to attack cancer cells.
Treatment
It is important to keep in mind that immune checkpoint inhibitors are not an effective or appropriate treatment for every case of non-small cell lung cancer. To determine if this is an appropriate treatment, an oncologist may order a test to determine if the cancer is PD-L1 positive. An oncologist may also prescribe an immune checkpoint inhibitor after a patient has undergone chemotherapy or radiation therapy for non-small cell lung cancer. Immune checkpoint inhibitors are delivered via a series of infusions.
It is also important to understand that, as with chemotherapy and radiation therapy, immunotherapies damage healthy cells in addition to cancer cells, and can cause a number of side effects.
The treatment recommended by an oncologist will depend on a number of factors, including the type of non-small cell carcinoma, the stage of the cancer and the size and locations of the tumors. Treatment will also depend on the overall health of a patient and the patient’s medical history.
