New treatment for triple-negative breast cancer

Immunotherapy for cancer, including breast cancer, is a treatment method that helps the body's immune system fight cancer. The immune system is our natural defense system, which detects and destroys foreign substances such as viruses, bacteria, as well as cancer cells. Immunotherapy attempts to enhance this natural process.

What is the immune system?

Our immune system is a complex network of cells, tissues and organs that primarily protects the body from pathogens such as bacteria, viruses, fungi and parasites. The immune system works by recognizing and destroying these invaders.

For external intruders, such as viruses and bacteria, our body has several lines of defense: the skin, mucous membranes (e.g., nasal mucosa captures pathogens and pushes them out again when we blow our nose) and stomach acid (destroys pathogens ingested through food). Intruders that get through the first barriers and into our tissues are recognized there as foreign to the body and attacked by specialized immune cells.

The immune system not only responds to outside invaders, but it can also notice changes taking place inside the body. For example, when a normal cell transforms into a cancer cell, abnormal proteins sometimes appear on the surface of this cancer cell, which immune cells recognize as foreign to the body. These immune cells sound the alarm and activate specialized immune cells that then go on to attack and possibly destroy the cancer cells.

However, cancer cells often manage to escape such an immune system attack by secreting substances that neutralize these immune cells or by altering the abnormal proteins on their surface so that immune cells no longer recognize them. Immunotherapy aims to block these escape routes and thus strengthen and support the natural defenses against cancer.

How does immunotherapy work in breast cancer?

Immunotherapy is especially effective in certain types of breast cancer, such as triple-negative breast cancer, that do not respond as well to traditional treatments such as hormone therapy and chemotherapy. Currently, there is already an effective immunotherapy for triple-negative breast cancer that blocks the cancer cells' reaction against immune cells. These drugs allow the immune system to block the cancer cells' escape routes which can lead to their destruction. Studies show that immunotherapy can improve the survival of patients with early-stage, advanced or metastatic triple-negative breast cancer. Immunotherapy is already being used, often in combination with chemotherapy.

The effectiveness of immunotherapy can vary: and not all patients will respond equally well to these treatments. As with other cancer therapies, immunotherapy can also cause side effects. These are somewhat different, however, since they involve the immune system. For example, the immune system may accidentally attack healthy cells, which then gives rise to unwanted effects.