Immunotherapy treatment for cancer – Everything you need to know
What is immunotherapy?
Immunotherapy is a treatment that uses certain parts of a person’s immune system to treat cancer. Immunotherapies work by slowing the growth and spread of cancer cells, and by aiding the immune system to destroy existing cancer cells.
Immunotherapy for cancer: How does it work?
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 of immunotherapy stimulate and use the immune system to treat the cancer.
What are ‘checkpoint’ immunotherapy drugs?
Cancer cells find ways to stop the immune system from destroying them, by setting up barriers or ‘checkpoints’ so the immune system cannot recognise them. Cancer cells also mutate to avoid being found by the immune system.
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 germs and abnormal cells and work together to remove them. Checkpoint inhibitors help T-cells to recognise and remove or reduce cancer.
Checkpoint immunotherapy drugs or checkpoint inhibitors are drugs that block these checkpoints so that the T-cells can once again find the cancer cells.
What types of cancer can be treated with immunotherapy?
To treat cancer using immunotherapy, a cancer specialist will consider the type and stage of cancer, the patient’s treatment history, the future treatment options and the patient’s overall health.
Immunotherapy is available for some types of cancer, including bladder cancer, head and neck cancer, Hodgkin and non-Hodgkin lymphoma, kidney cancer, liver cancer, lung cancer, melanoma and Merkel cell carcinoma. So far, most people who have been treated with checkpoint inhibitors have had advanced cancer. Advanced cancer means either the cancer has come back and spread after the initial treatment, or it was at an advanced stage when first diagnosed. For some cancer types, such as melanoma, immunotherapy is starting to become available for earlier-stage cancers.
Unfortunately, immunotherapy is not yet an option for most people living with cancer. Right now, it’s only effective for 30% of people with advanced lymphoma, kidney, bladder, or lung cancer. The percentage is higher for advanced melanoma, at 50% – but people with breast, prostate and pancreatic cancer rarely respond.
What are the different types of immunotherapy?
There are three main groups of immunotherapy treatments which include monoclonal antibodies, nonspecific immunotherapies, and cancer vaccines.
When the body detects harmful viruses, bacteria, and/or other substances that cause diseases, antibodies are naturally produced. Antibodies fight infection or disease by targeting parts of cancer cells to alter their growth. Monoclonal antibodies are made in a laboratory to work and mirror this process. They are usually given intravenously, injected into a vein.
Monoclonal antibodies may be designed to change cancer cells in different ways, including:
- Antibodies can attach to cancer cells to alert your immune system to destroy that cell.
- Antibodies can slow the growth of cancer cells by blocking parts of the cell, preventing growth.
- Radioimmunotherapy uses antibodies to deliver radiotherapy to cancer cells without damaging healthy cells. This is done by attaching radioactive molecules to antibodies in a medical laboratory. These kinds of antibodies can also be used to diagnose some cancers by flagging where cancer cells exist in the body.
- The antibody may carry medicine directly to cancer cells, for example chemotherapy.
Nonspecific immunotherapies refer to the use of cytokines (proteins produced by white blood cells to control immune responses) to help the body’s immune system destroy cancer cells. Nonspecific immunotherapies are typically given in combination with other cancer treatments, such as chemotherapy or radiation therapy.
Types of cytokines that are made in a laboratory to treat cancer include:
- Interferons, which can help the immune system to slow the growth of cancer cells.
- Interleukins, which can increase the production white blood cells and antibodies to treat cancer.
- Hematopoietic growth factors, which may be used to counteract some side effects of chemotherapy.
How effective is immunotherapy for cancer?
The most challenging issue is that immunotherapy and checkpoint inhibitors don’t work for everyone. If immunotherapy is recommended as a treatment, it is often difficult to predict whether it will work. The immunotherapy success rate varies greatly depending on the type of cancer and many individual factors, such as the stage of cancer, the patient’s treatment history and future treatment options, and the patient’s overall health.
Currently, immunotherapy is only effective for 30% of people with advanced lymphoma, kidney, bladder, or lung cancer. To make immunotherapy available to more people in the future, researchers are trying to understand why some people’s cancers respond better than others.
How long can you stay on immunotherapy for 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 afterwards. 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.
What are the side effects of immunotherapy?
Immunotherapy side effects are different to the side effects of other cancer treatments and need to be managed differently. Side effects can begin within days of starting treatment, but more commonly they occur several weeks or months after starting treatment. In some rare cases, new side effects can appear months after finishing treatment. Side effects are more likely to be severe if received in higher doses, in combination with multiple immunotherapy drugs, or if paired with other cancer treatments. Possible side effects of immunotherapy include:
- fever
- chills
- weakness
- dizziness
- headache
- nausea, vomiting and diarrhoea
- muscle or joint aches
- changes in weight
- low blood pressure
- fatigue
- breathing difficulties
- allergic reactions (rarely).
Skin reactions at the site of injection can also be experienced if immunotherapy is given intravenously. These include:
- pain
- swelling
- soreness
- redness
- itchiness
- rashes.
What is the difference between chemotherapy and immunotherapy?
Chemotherapy, targeted therapy, immunotherapy and hormone therapy are all drug therapies. They are known as systemic treatment because the drugs circulate throughout the body. The difference between chemotherapy and immunotherapy is that chemotherapy involves the use of specialised drugs to slow the growth of cancer cells directly whereas immunotherapy uses certain parts of a person’s immune system to treat cancer.
Read more about the different types of cancer treatment here.
How is immunotherapy administered?
Immunotherapy can be given in different ways, including:
- Orally, as pills (tablets, capsules) or liquid.
- Intravenously (injected into a vein).
- Topically, as a cream to rub onto skin.
- Intravesically, administered directly into the bladder.
Immunotherapy can be given in a clinic, a doctor’s office, or at a hospital. Like other cancer treatments, immunotherapies can be given in cycles. This is a period of treatment followed by a period of rest.
Did you know you can support breakthrough immunotherapy treatments?
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.
This world-first Australian-designed custom intravital microscopy centre at Garvan Institute will overcome the limitations of conventional microscopes in viewing the interactions between the immune system and cancer, below the surface of tumours and deep inside tissues. This work will 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.
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.
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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