For more than a century, doctors have attempted to harness the power of the body’s immune system to fight and defeat cancer. With virtually all other diseases, the immune system fights foreign invaders in your body to get you healthy again. But with cancer, this process doesn’t happen. For a long time, experts didn’t understand why. But discoveries in recent years have revealed the key to cancer’s ability to hide itself from the immune system. As a result, a new treatment called immunotherapy has emerged. Immunotherapy helps the immune system recognize cancerous cells as intruders, sending immune fighters into action. Today, immunotherapy for lung cancer offers hope where other treatments may have failed. If you have advanced lung cancer, your doctor may recommend immunotherapy alone or together with other, more conventional cancer treatments, like chemotherapy or radiation therapy. Immunotherapy for advanced lung cancer isn’t for everyone. Talking with your doctor about your treatment options is the best first step in determining which choices may be best for you. Your doctor can help you determine your eligibility based on the stage of your cancer, your overall health, and any other medical conditions you may have. How does immunotherapy work? Immunotherapy uses your body’s own immune system to fight cancer cells in your lungs. Normally, the cells, tissues, and organs of your immune system identify and attack any foreign or harmful substances inside your body, such as viruses, bacteria, or cancer cells. This is possible because certain immune system cells, called T cells, identify proteins on the surface of harmful substances. This causes your immune system to respond, which normally means killing and getting rid of these harmful substances. Cancer cells trick your immune system and prevent it from attacking them by making proteins that confuse T cells. When a T cell encounters a cancer cell, the T cell “reads” the proteins on the surface of the cancer cell. Because these proteins look like those found on normal body cells, the T cell does not sound the alarm for an immune system attack. Immunotherapy drugs help your body turn your immune system back on, allowing it to easily identify and attack cancer cells. This is accomplished in two ways: Checkpoint inhibitors: Immune checkpoint inhibitors work by blocking the proteins on the surface of cancer cells that prevent an immune system attack. Also, some types of checkpoint inhibitors work on T cells themselves by making them more likely to attack cancer cells. Monoclonal antibodies: Also known as targeted therapy, monoclonal antibodies are large molecules that target specific sites on the outside of cancer cells. Some types of monoclonal antibodies help immune system cells recognize and kill cancer cells, while others interfere with the cancer cell itself. What’s the treatment process? Immunotherapy drugs for advanced lung cancer are typically given through an intravenous (IV) infusion directly into a vein. Your treatment may be administered in your doctor’s office, clinic, or in a hospital. However, if your treatment occurs at a hospital, you probably won’t have to spend the night after your procedure is complete. Your immunotherapy dose and dosing schedule depends on how advanced your lung cancer is, your overall health, and any other medical conditions you may have. In many cases, doctors recommend one or two immunotherapy infusions every few weeks. What possible side effects should you expect? Like any medical treatment, immunotherapy drugs for lung cancer may cause certain side effects. In many cases, people experience very mild or no side effects, but it is possible to have more serious complications. Your side effects may include: Cough Diarrhea Fatigue Muscle and bone pain Nausea and loss of appetite Shortness of breath Rash If you experience any side effects while receiving immunotherapy, it’s important to tell your doctor immediately. How will you know if immunotherapy is working? To gauge the effectiveness of immunotherapy, your doctor will examine you frequently. You should also expect to have multiple medical tests, like blood tests or medical imaging tests, which can help your doctor determine if the lung cancer is responding to your treatment. There is no way to predict how your body will respond to immunotherapy, but working with your doctor can help you decide whether this type of treatment could be right for you. There are several immunotherapy drugs for advanced lung cancer available on the market today, and several more are under investigation in ongoing clinical trials. Speak with your doctor to determine whether this innovative new type of treatment could help you more effectively manage advanced lung cancer.