What is cancer immunotherapy?

Immunotherapy, sometimes called biological therapy, is a type of cancer treatment that works by boosting a person's own immune system to fight the cancer. Immunotherapy is currently approved in Australia for some types of cancers, and is also being trialled for other cancers.

The therapy is not right for everyone so if you have cancer, you will need to discuss with your doctor whether it could benefit you.

How does immunotherapy work?

Usually, your immune system fights 'foreign' cells that cause illnesses and disease. However, some bacteria, viruses and cancer cells find a way to stop your immune system from destroying them and then spread through your body.

Immunotherapy works by either:

• improving your immune system to attack the foreign cells; or
• removing whatever is preventing your immune system from attacking the cells

The treatment of cancer is one important area in which immunotherapy is used.

When is immunotherapy used to treat cancer?

In Australia, immunotherapy is currently not used as often as other cancer treatments such as radiotherapy, surgery or chemotherapy.

Depending on whether it is suitable for a person and their circumstances, immunotherapy may be used to treat:

• some types of cancer in the head, neck, lung, kidney, liver or bladder
• melanoma
• Hodgkin lymphoma
• Merkel cell carcinoma (a rare type of skin cancer)

It is also being trialled for other cancers, including leukaemia and breast cancer.

Immunotherapy is mostly used for cancer that is already advanced when diagnosed, or that has come back and spread after treatment. At this stage, it appears that immunotherapy may work better for people who have fewer or no symptoms of cancer.

When considering whether immunotherapy is right for you, your doctor will look at:

• your general health
• what type of cancer you have
• how much the cancer has grown or spread
• what kind of treatment you've had already

What are the types of cancer immunotherapy?

Monoclonal antibodies (mAbs)

These either:

• attach to cancer cells and alert your immune system to destroy them
• block parts of the cancer cell to slow down its growth
• carry radiotherapy or chemotherapy therapy directly to the cancer cell to attack it

The most common type of immunotherapy used in Australia is a type of mAb known as checkpoint inhibitors. Checkpoint inhibitors produce a type of protein which exposes cancer cells that have been hiding from your immune system. Your T-cells (fighter cells) can then notice and attack the cancer.

Other types of immunotherapy

• Immune stimulants: stimulate the immune system to attack the cancer.
• Adoptive cell transfer: this experimental therapy boosts the ability of the T-cells to find cancer.
• Oncolytic viruses: infect tumour cells and cause an immune response against the infected cells.

Cancer vaccines

Cancer vaccines help your body discover cancer cells. There are 2 types:

• preventative cancer vaccines, to prevent some types of cancer caused by infections
• treatment vaccines, to help your body fight cancer that already exists

Read more about the different types of immunotherapy on the Cancer Council website.

How is immunotherapy given?

Depending on the type of immunotherapy, it can be administered by:

• swallowing a pill or liquid (orally)
• injecting into your vein (intravenously)
• rubbing a cream onto your skin (topically)
• putting it directly into your bladder (intravesically)

How often and how long you have immunotherapy depends on:

• the type and stage of cancer
• the type of immunotherapy and how you respond to it
• what side effects you experience

What are the benefits of immunotherapy for cancer?

Although response to immunotherapy can vary from person to person, compared to other cancer treatments, benefits of immunotherapy such as checkpoint inhibitors can be:

• targeting cancer cells without harming your healthy cells
• improving outcomes in some types of cancer
• the side effects are generally thought to be milder
• sometimes shrinking a tumour to a size, or moving it to a location, where it can be surgically removed

What are the possible side effects of immunotherapy?

Common side effects include:

• eye inflammation, causing dry, irritated eyes
• joint inflammation, causing joint pain
• bowel inflammation, causing stomach pain, blood in the faeces (poo), bloating and diarrhoea
• dermatitis, causing skin rashes
• tiredness
• thyroid problems, leading to weight loss or weight gain
• diarrhoea, abdominal pain and bloating

Less common side effects:

• headache and changes in eyesight
• dry eyes
• lung inflammation, causing coughing and shortness of breath
• liver inflammation, causing yellow skin, dark urine and abdominal pain
• excessive thirst or urination

More information

• Read the Cancer Council's factsheet on immunotherapy
• Watch the Peter MacCallum Cancer Centre videos on what to expect from immunotherapy