How Does Immunotherapy Work?

How does immunotherapy work against cancer? 

Immunotherapy is a treatment that uses the body’s own immune system (a collection of organs, special cells and substances that help protect from infections and some other diseases) to treat cancer. There are several types of immunotherapy, and each works differently. 

Checkpoint inhibitors are drugs that allow the therapy or T-cells (the immune system’s T-cells circulate throughout the body looking for abnormal cells to destroy) to find and reduce the cancer. Other types stimulate the immune system to help it work better against cancer.

What happens to the body during immunotherapy?

Modern immunotherapy drugs try to help the immune system in very specific ways. The white blood cells known as lymphocytes are an important part of the immune system. There are two main types of lymphocytes – T-cells and B-cells. They travel throughout the body looking for abnormal cells and work together to remove them.

Checkpoint inhibitors help T-cells to recognise and remove or reduce the cancer. Checkpoint inhibitors are drugs that block checkpoints so that the T-cells can once again find the cancer cells. 

Checkpoint inhibitors trigger an immune response that can lead to redness, swelling or pain (inflammation) anywhere in the body. Side effects will depend on which part of the body becomes inflamed and often depend on the drug used and how the body responds. While some people have serious side effects, others have just one or two mild side effects.

How long does it take for immunotherapy to start working against cancer?

Immunotherapy is usually administered to an outpatient, which means the patient visits the hospital or treatment centre for the infusion and then can go home after. Treatment is commonly given in repeating cycles, with rest periods of 2–6 weeks in between. 

The length of treatment or how often it occurs can depend on how advanced the cancer is, the type of cancer, the side effects experienced and the type of immunotherapy treatment. Many people stay on immunotherapy for up to two years. Immunotherapy can take weeks or months to start working, depending on how the immune system and the cancer respond. 

Most cancers have treatment protocols that set out which drugs to have, how much and how often the body can tolerate. 

What are the signs that immunotherapy is working?

It may take some time to know if immunotherapy has worked because people often have a delayed response. In some cases, the cancer may appear to get worse before improving. 

You may wonder whether having side effects means the immunotherapy is working. Side effects are a sign that the treatment is affecting your immune system in some way, but this may or may not mean the treatment is affecting the cancer. 

Many people with mild side effects have still seen improvements. A good response seen from immunotherapy is when the cancer has shrunk or disappeared. In some cases, the cancer will also remain stable, where it does not grow but also does not shrink or disappear. People with stable disease often continue to have a good quality of life.

Related reading: Immunotherapy for Cancer Treatment: A Clear Guide

Are there any disadvantages of immunotherapy for cancer?

Not everyone is able to receive immunotherapy. Unfortunately, immunotherapy and checkpoint inhibitors do not work for everyone. Some cancers will not respond to the treatment at all, or the cancer cells can become resistant to the treatment even if it works at first. This can be very disappointing, however there are other treatment options to explore as well.

Like all cancer treatments, side effects can be quite common. If left untreated, side effects can become serious and may even be life-threatening. If this is the case, it is always best to inform your doctor. Common side effects include headaches, nausea, vomiting, change in weight, and dizziness.

Back brilliant cancer treatments like immunotherapy today

ACRF is committed to backing the brilliant ideas needed to find new ways to prevent, detect and treat all types of cancer, so that we can reach our vision of a world without this devastating disease.

For example, ACRF awarded a $3 million grant to help establish the ACRF Centre for Intravital Imaging of Niches for Cancer Immune Therapy at Sydney’s Garvan Institute of Medical Research. Learn more about the cutting-edge cancer research project working to address a major challenge in the treatment of cancer: why some patients have a remarkable clinical response to cancer immunotherapies, while other patients do not respond to this treatment. 

By donating to ACRF, you are helping to provide scientists with the tools, technology and infrastructure they need to accelerate cancer research. Click here to see donation options or make a donation today.


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