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Cancer immunotherapy explained

Your doctor may discuss immunotherapy as a treatment option, depending on the stage and type of cancer you have. The video and other information below may help you understand more about immunotherapy.

The information on this website should be discussed with your healthcare professional and does not replace their advice.

What is Immunotherapy?

Your immune system is your body’s natural defence against diseases, including cancer. Cancer immunotherapy helps your immune system do what it is designed to do: help your own body fight cancer.

Watch our Introduction to Cancer Immunotherapy video.

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The immune system and cancer

You may know that your body can find and fight germs, such as a virus that causes a cold. This is known as an immune response.

In the same way, our immune response protects us from cancer. It usually detects and destroys abnormal cells before they can develop into cancer.

The problem is that some cancer cells can hide from our immune system. They survive and grow by setting up barriers that make it difficult for the immune system to find them.

An icon of a shield blocking a cancer cell.

How does immunotherapy work?

There are different types of immunotherapies. Some may help strengthen the immune system to fight cancer. Others are designed to enable the immune system to find and fight cancer.

This type of immunotherapy is known as a checkpoint inhibitor. Checkpoint inhibitors remove the barriers cancer cells set up to help them hide from the immune system.

KEYTRUDA® (pembrolizumab) is a checkpoint inhibitor. Click here to read more about KEYTRUDA.

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When is immunotherapy used?

Immunotherapy may be given to patients who have just been diagnosed with certain types of advanced cancer or in some cases to patients whose cancer has come back after the initial treatment.

In other cases, it may be given to patients with certain earlier-stage cancers.

Immunotherapy may be given alone or in combination with other treatments, such as chemotherapy.

An icon of an IV drip bag.


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Patient Resources


Cancer Council Australia. 2021. Understanding Immunotherapy. A guide for people affected by cancer.
Available at:
Accessed on 02/06/2022

Cancer Society New Zealand. 2023. Immunotherapy.
Available at:
Accessed on 01/09/2023


NZ-KEY-00864. TAPS DA 2339KN TAPS NP20132. First Issued February 2024.