Cancer immunotherapy. How does it work?

Cancer immunotherapy is a relatively new method of treatment. In 2016, the American Society of Clinical Oncology (ASCO) recognized cancer immunotherapy as the greatest achievement of oncology in 2015. It is based on the use of the natural properties of the immune system, which is responsible for fighting back various types of infections in the body with white blood cells and lymphatic system. But how exactly is it used in the fight against cancer?

Immunotherapy – what is it?

Immunotherapy is a method of supporting the body by using molecules that exist in the body and are naturally produced by it. This group includes molecules that modulate the reactions of the immune system and molecules that are created in response to the appearance of an intruder in the body – allergen, virus or even cancer cells. Thanks to these properties, it is used as a treatment or support of the body in the fight against various autoimmune diseases. Immunotherapy is commonly used to desensitize patients suffering from allergies. The dynamic development of medicine has allowed the introduction of immunotherapy as one of the methods of fighting cancer.

How does cancer immunotherapy works?

The organism in which cancer cells have started to develop, naturally tries to fight them by sending immune cells to the correct area. Unfortunately, in many cases, cancer has the ability to "hide" and thus the immune system does not respond adequately to its presence. It may also be because cancer cells grow from healthy cells located in the body. As a result, the response of the immune system may not be strong enough to fight the cancer, or the body will not recognize the cancer cells as foreign. Scientists have not yet found the direct cause, but have developed a method that is able to stimulate the body to fight cancer cells on its own - cancer immunotherapy. During the treatment the patient takes drugs that stimulate the immune system. In most cases, it is used as a complement of standard cancer treatments, such as chemotherapy or radiotherapy.

Immunotherapy in the treatment of cancer

There are two types of cancer immunotherapy which are divided by the way in which the body responds:

• Specific (targeted) immunotherapy – it works by targeting the immune system to a specific type of cell in order to fight them; it includes anti-cancer vaccines and monoclonal antibodies;
• Non-specific (non-specific) immunotherapy – it stimulates the immune system to improve its functioning; it includes immunostimulants, monocytes, cytokines, and LAK cells.

Additionally, specific immunotherapy can be divided into active and passive. Vaccines used in active immunotherapy are created on the basis of tumor cells derived from the patient or tumor antigens. On the other hand, passive immunotherapy uses vaccines containing antibodies, most often monoclonal antibodies that are directed against specific cells. In turn, non-specific immunotherapy uses drugs which task is to inhibit the development of cancer and stimulate the immune system to work more intensively and fight cancer cells.

When is immunotherapy used?

Research into the immune system's responses to cancer cells is still ongoing, and the method of immunotherapy itself is under constant development. At the moment, there are many clinical trials involving other molecules, which are likely to be introduced on a larger scale soon. At present, it is widely used to treat lung cancer, melanoma, kidney cancer, head and neck cancers and Hodgkin's lymphoma.