Immunotherapy for breast cancer

Immunotherapy is sometimes used to treat locally advanced or metastatic triple-negative breast cancer. Immunotherapy helps to strengthen or restore the immune system’s ability to fight cancer. Immunotherapy is sometimes called biological therapy.

You may have immunotherapy to:

• kill breast cancer cells
• stop breast cancer tumours from growing and spreading
• control symptoms of metastatic breast cancer

Your healthcare team will consider your personal needs to plan the drugs, doses and schedules of immunotherapy. You may also receive other treatments.

The immune system normally stops itself from attacking normal cells in the body by using specific proteins called checkpoints, which are made by some immune system cells. Breast cancer cells sometimes use these checkpoints to avoid being attacked by the immune system.

Immune checkpoint inhibitors are drugs that work by blocking the checkpoint proteins so that immune system cells (T cells) attack and kill the cancer cells. Immune checkpoint inhibitors are monoclonal antibodies that find and attach to a specific antigen on a cancer cell.

Atezolizumab (Tecentriq) is an immune checkpoint inhibitor used in combination with nab-paclitaxel (Abraxane) to treat advanced or metastatic triple-negative breast cancer that expresses the PD-L1 protein.

Pembrolizumab (Keytruda) is an immune checkpoint inhibitor used in combination with chemotherapy as neoadjuvant therapy for high-risk early-stage triple-negative breast cancer. It is continued as adjuvant therapy after surgery.

Side effects can happen with any type of treatment for breast cancer, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

Side effects of immunotherapy will depend mainly on the type of drug or drug combination, the dose, how it’s given and your overall health. Atezolizumab may cause these side effects:

• fatigue
• decreased appetite
• nausea and vomiting
• infection
• constipation
• fever
• diarrhea
• low white blood cell count
• cough

Be sure to report side effects to the healthcare team. Side effects can happen any time during, immediately after or a few days or weeks after immunotherapy. Sometimes late side effects develop months or years later. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.  

Your healthcare team is there to help. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Details on specific drugs change regularly. Find out more about sources of drug information and where to get details on specific drugs.

Find out more about immunotherapy. To make the decisions that are right for you, ask your healthcare team questions about immunotherapy.