What is immunotherapy?

What is the immune system?

Your immune system is your body’s natural defence system. It’s made up of cells, tissues, and organs that work together to protect your body from harmful substances known as pathogens. Pathogens include bacteria, viruses, and fungi that can cause diseases.

Your immune system reacts when your body comes into contact with a pathogen. One example of an immune response is inflammation. White blood cells called B-cells and T-cells are also activated to find and destroy pathogens.

Your immune system also remembers pathogens. If you are infected again, your immune system makes antibodies. These antibodies recognise and neutralise pathogens before they can make you ill. This is known as having immunity. Vaccines help you gain immunity to diseases without having to experience the illness.

Your immune system is only supposed to target foreign substances, and not your own cells. In autoimmune diseases your immune system mistakenly attacks your healthy cells.

You might be wondering why the immune system doesn’t attack cancer cells. Cancer cells can evade your immune system or weaken it. This allows cancer to develop.

How does immunotherapy work?

The aim of immunotherapy is to help the immune system fight cancer. This can be through enhancing your own immune system response or by marking cancer cells to be destroyed.

Here are different types of immunotherapy treatment and how they work.

• Monoclonal antibodies are made to recognise cancer cells and attach to them. This can then help make the cancer cells more visible to the immune system and mark them to be destroyed.
• Checkpoint inhibitors are a type of monoclonal antibody. They work by blocking brakes called immune checkpoints, which usually stop the immune system from overreacting. By turning off these brakes, the immune system can better find and destroy cancer cells.
• Immune system modulators are used to boost your immune response. These may be drugs you take as tablets. Cytokines are also a type of immune system modulator. These are proteins made naturally in your body. Cytokine treatment can promote the immune response and slow cancer growth.
• Chimeric antigen receptor (CAR) T-Cell therapy involves using your own T-cells. It’s also known as an advanced therapy. Your T-cells are taken from your body and used to create modified T-cells. They are then put back in your body to target and kill cancer cells.
• Cancer vaccines help your immune system recognise and attack cancer cells. Bladder cancer for example can be treated with a vaccine. But cancer vaccines are mostly still under study in clinical trials.

How is immunotherapy administered?

The way immunotherapy is given depends on the type you’re having. You might receive immunotherapy treatment:

• via an injection in your skin
• via infusion in your vein (through a drip)
• orally (by mouth) as tablets or capsules
• as a cream
• directly into your bladder via a catheter (for bladder cancer)

Immunotherapy may be given in combination with other cancer treatments such as chemotherapy.

What types of cancer can be treated with immunotherapy?

Immunotherapy is not as widely used as chemotherapy, surgery, and radiotherapy. Some of the cancers it can be used to treat may include:

• breast cancer
• lung cancer
• cervical cancer
• leukaemia
• prostate cancer
• ovarian cancer
• bladder cancer

Your doctor can advise whether immunotherapy is an option for you as a cancer treatment. This will depend on:

• the type of cancer you have
• if and where the cancer has spread
• genetic changes in your own genes or the cancer’s
• your general health

How long does immunotherapy take?

How long an immunotherapy treatment session takes depends on the type you are having. An injection can take at least 10 minutes. If you are having intravenous treatment (through a vein), this can be a few hours.

Immunotherapy is usually given in cycles. You have a few treatment sessions, then a break so your body can recover. The treatment session and the rest period make up one treatment cycle. Your cancer team can explain how many treatment cycles you will have.

What are the side effects of immunotherapy?

All treatments can have side effects. The side effects of immunotherapy can depend on which type you are having. Some people may have mild side effects, but others may have more severe ones.

Some sides effects include flu-like symptoms such as fever, chills, headache, and feeling tired. You might also have diarrhoea and muscle pain. Immunotherapy via injection may lead to a rash or swelling at the injection site. Immunotherapy can cause hair thinning or in some cases hair loss, but less commonly compared to chemotherapy.

Immunotherapy can increase the activity of your immune system. This may lead to inflammation and autoimmune complications (where your immune system attacks your own healthy cells) in any part of your body.

Your healthcare team will talk to you about the possible side effects before you have immunotherapy treatment. They will help you cope with any side effects and reduce them, for example by using steroids.