Immunotherapy

What is immunotherapy?

The immune system is made up of cells and organs that protect the body from threats such as infections, toxins and abnormal cell growth. The immune system recognises when a foreign organism, such as a germ, enters the body and attacks it to stop it from harming the body.

Immunotherapy, or biologic therapy, is a type of treatment that uses your own immune system to fight cancer.

Even though the immune system can prevent or slow cancer growth, cancer cells have ways to avoid destruction by the immune system. For example, cancer cells may:

• have genetic changes that make them less visible to the immune system

• have proteins on their surface that turn off immune cells

• change the normal cells around the tumour so they interfere with how the immune system responds to the cancer cells

Immunotherapy helps the immune system to better act against cancer.

Types of immunotherapy treatments

There are many different kinds of immunotherapy which work in different ways.

• Cancer vaccines – medicines that trigger the body’s immune system to prevent cancer cells from developing or fight existing cancer cells.

• Monoclonal antibodies – also known as therapeutic antibodies, these are immune system proteins designed to attach to specific targets found on cancer cells so that they will be better seen and destroyed by the immune system.

• Checkpoint inhibitors – medicines that help the immune system respond more strongly to a tumour by releasing “brakes” that keep T cells (a type of white blood cell and part of the immune system) from killing cancer cells.

• CAR T-cell therapy – an emerging type of treatment in which a patient’s T-cells (a type of immune system cell) are made in the laboratory to have specific receptors that bind to their counterpart proteins on cancer cells. This allows the immune cells to attack the cancer cells when they are introduced back into the body.

What are the side effects of immunotherapy?

Immunotherapy side effects can affect people in different ways and will depend on how healthy you are before treatment, your type of cancer, how advanced it is, the type of therapy you are getting, and the dose.

The most common side effects are skin reactions at the needle site, which can include pain, swelling, soreness, redness, itchiness and a rash. You may experience flu-like symptoms, such as fever, chills, weakness, dizziness, nausea or vomiting, muscle or joint aches, fatigue, headache, trouble breathing, and low or high blood pressure.

Other side effects might include swelling and weight gain from fluid retention, heart palpitations, sinus congestion, diarrhoea and risk of infection. Immunotherapy can cause side effects, many of which happen when the immune system that has been revved up to act against the cancer also act against healthy cells and tissues in your body.

Rarer side effects of some immunotherapies, such as immune checkpoint inhibitors can include widespread inflammation.

Depending on the organ of your body that is affected, inflammation can lead to:

• changes in skin colour, rash, and feeling itchy, caused by skin inflammation

• cough and chest pains, caused by inflammation in the lungs

• belly pain and diarrhoea, caused by inflammation in the colon

• diabetes, caused by inflammation in the pancreas

• hepatitis (inflammation of the liver)

• hypophysitis (inflammation of the pituitary gland)

• myocarditis (inflammation of the heart muscle)

• nephritis (inflammation of the kidney) and impaired kidney function

• overactive or underactive thyroid

• nervous system problems such as muscle weakness, numbness, and trouble breathing