Immunotherapy
What is the Immune System?
Immunotherapy is a treatment that works with your body’s immune system to help it recognize and attack cancer. To understand immunotherapy, think about what the immune system does. The immune system is a complex group of cells, tissues, and organs that protect you from germs and illnesses, such as the flu and chickenpox.
When an invading organism enters your body, your immune system goes to war. It sends fighter cells to attack and remove the invaders. Once these invaders are removed, the immune system remembers what they look like and stays on guard for the next attack.
Immune Checkpoint Inhibitors
Checkpoint inhibitors are the most widely used type of immunotherapy drugs. These medicines act like a light switch to help the immune system turn on to spot and attack cancer.
Immune checkpoint inhibitors are used with chemo in triple negative breast cancers. Immunotherapy added to chemo provides benefits when administered prior to surgery in patients with stage II or III triple negative breast cancer. In the advanced or metastatic setting, immunotherapy is only helpful in patients whose tumors are PD-L1 positive. PD-L1 is a protein on the surface of some cancer cells that interacts with the PD-1 protein on immune system cells to thwart an immune attack on the cancer. Immunotherapy can also be considered if your tumor has a high tumor mutation burden (TMB). This means that the tumor has many genetic mutations or changes. If your tumor has a high TMB then immunotherapy medicines may be more effective.
All About Pembrolizumab (Keytruda®)
Pembrolizumab (Keytruda®) is an immunotherapy drug known as a PD-1 inhibitor. PD-1 is a protein found on T cells (a type of immune cell) that normally acts as a brake to prevent the immune system from attacking healthy tissue. Some cancer cells take advantage of this brake to avoid being recognized and attacked.
By blocking PD-1, pembrolizumab helps release that brake, allowing the immune system to better recognize and respond to breast cancer cells. In many cases, this can help shrink tumors.
When is pembrolizumab used in breast cancer?
How is it given?
Possible Side Effects of Immunotherapy
Because immunotherapy works by activating your immune system, its effects are not limited to just the tumor. In some cases, the immune system may also affect healthy tissues in different parts of the body.
Side effects can develop soon after treatment begins, several weeks into therapy, or even months after treatment has ended. For this reason, it’s important to stay in close communication with your care team and report any new or unusual symptoms promptly.
