Even though the study of immunotherapy has been around for more than a century, its value to the treatment of cancer is greater today than ever. Drug development is progressing rapidly, data from clinical trials continues to impress, and, most important, more and more patients are experiencing remarkable responses to these treatments that allow them to lead longer, healthier lives. As news stories highlight these groundbreaking results, patients are beginning to wonder, “What is it? Is it a cure? Could it be right for me?”
Simply stated, immunotherapy is a type of treatment that helps the body’s immune system attack cancer. And recent breakthroughs in immunotherapy for melanoma and lung cancer continue to significantly impact the treatment of both of these common cancers, and influence progress in the treatment of several other cancer types.
An increasing number of immunotherapy drugs have been approved by the FDA (U.S. Food and Drug Administration) to treat different cancer types—some drugs even being used across several cancers. Their success has been so impressive that it has launched immunotherapy into a standard-of-care spot next to long-standing treatment options such as chemotherapy and radiation. This treatment is still relatively new, however, so many of these “astonishing” results are coming from patients participating in clinical trials, which are the studies of drugs or treatment combinations not yet approved by the FDA. Patients can still gain access to these treatments through the clinical trials, so it’s important to discuss this opportunity with your doctor when considering treatment options.
Immunotherapy and the immune system are both very complicated, and scientists continue to learn more every day. Whether you’ve just heard of immunotherapy or you’re considering it as a treatment option, it’s important to learn as much as you can so you can make informed decisions about your cancer care.
Cancer vs. The Body: The 3 E's
In the 1950s, researchers thought the immune system did two things: it protected your body against bacteria and viruses, and it looked for abnormal cells and killed them before they could become tumors. Called the cancer immunosurveillance theory, it was initially rejected. In the last 10 years, however, studies have shown that immune cells are indeed important in the prevention of cancer. Although tumors may develop in a functioning immune system, the way a tumor grows and develops is influenced by the body’s immune response. Based on this new evidence – and confirmed by the mouse tumor studies conducted by Dr. Robert Schreiber – the theory has been renamed “cancer immunoediting.”
The three E’s of Dr. Schreiber’s theory of cancer immunoediting are elimination, equilibrium and escape:
Elimination – In this phase, the immune system sees and destroys cancer cells. This phase suggests that our bodies may be regularly introduced to cancerous changes and that our immune systems are capable of handling and eliminating them.
Equilibrium – If the cancer cells are not destroyed right away, they may exist in a delicate balance between growth and control by the immune system. During equilibrium, the body’s immune system is able to keep the cancer cells under control but is unable to kill them completely. In this phase, a tumor may remain dormant for an unknown length of time, and may evade medical testing. According to the theory, however, the constant interactions between the tumor cells and the T cells of the immune system may actually lead to tumors that can adapt to the immune response (see here for more information). This means the immune system may no longer be able to find tumors and attack them. Tumors that avoid the immune response can no longer be controlled and move on to the third phase.
Escape – The escape phase refers to the disruption of equilibrium (balance) that leads to immunosuppression. This allows the tumors to escape and begin growing in an environment of immune “tolerance.” It’s at this point that the symptoms of cancer begin to appear. Tumors in the escape phase use a number of methods to alter the body’s immune response in such a way that actually allows them to grow.