Q.

One of the most common misconceptions in cancer treatment is that all anti-cancer drugs are chemotherapy. In fact, over the last ten years treatments have incorporated “targeted therapy” and immunotherapy to allow patients to experience better outcomes and less side effect profiles. Traditional chemotherapy is the use of chemicals to stop cells from undergoing their natural division process (cancer cells do at a rapid rate). Unfortunately, these chemicals produce a significant amount of collateral damage including hair loss, nausea/vomiting, neurologic damage, and decreased blood counts. The decrease in blood counts

WHAT IS IMMUNOTHERAPY AND HOW IS IT USED TO TREAT CANCER?

immune or defense cells of the body, putting patients in danger of life-threatening infections. Targeted therapies are drugs that are designed to “target” a specific malfunction in the cancer cell which drives the cell to replicate and travel outside of its natural environment. Immunotherapy are drugs which harness the patient’s own immune system to identify and/or attack the cancer or local environment of the cancer. Interestingly, some classes of immunotherapy agents are designed to increase the immune systems activity and may result in a hyperactive response to the patient’s own body.

Immunotherapies have allowed us to treat many different types of cancer with the same agent. For instance, the checkpoint inhibitors such as nivolumab (Opdivo®) and pembrolizumab (KEYTRUDA®) are an intravenous medications approved for multiple cancers such as non-small cell lung cancer, melanoma, several gastrointestinal cancers, certain types of breast cancer, liver cancer,

Jennifer L. Cultrera, MD

and kidney cancer. This class of drugs does not actually hit the cancer cell itself, but instead a specific target called PDL-1 or PD receptor. These proteins tell the patient’s immune system to “move along” past the cancer cell by disguising itself as one of the patient’s healthy normal cells. Checkpoint inhibitors are antibodies, a protein that the body uses to activate the immune system, that disables PD receptor or PDL-1 thereby removing the “shield” around the cancer cell and allowing the body’s defenses to recognize and react/kill/disable the cancer cell anywhere the immune system reaches. Unlike chemotherapy, immunotherapy many continue to work even after administration of the agents are completed. The immune system “learns” to identify the cancer cells and creates a lifelong memory cell to help activate the immune system again should the same cancer cell appear in the body. Nivolumab and pembolizumab are not the only agents in this class and there are ongoing clinical trials around the world investigating novel strategies to attack cancer. Utilizing these therapies, certain cancers, such as stage IV lung cancer measured a patient’s overall survival in months only 5 years ago and is now measured in several years with a good quality of life.

Immunotherapy does have adverse effects that both patients and their team of physicians should understand. As the immune system is stimulated to react against the cancer cell, the same can happen against normal cells of the body, especially if the patient already suffers from an illness where the immune system is already activated (such as autoimmune disorders, i.e. Rheumatoid Arthritis, Lupus, or Psoriasis). Side effects will happen in a minority of patients, but if they occur can result in rash (dermatitis), vision changes (retinitis), bone pain (arthritis), breathing difficulties due to lung inflammation (pneumonitis) and other effects on the body. It is difficult to predict who will suffer from this and patients are watched closely in conjunction with other members of their medical team should side effects occur.

Although by themselves immunotherapy may not be the silver bullet in our cancer treatment arsenal, new combinations with chemotherapy, targeted therapy and even vaccines using the patient’s immune system exposed their specific cancer are being investigated and used on a daily basis. Through this research we are continuously advancing the science of personalized cancer care.