Immunotherapy treatment for cancer

Find out more about immunotherapy treatment, how it works and, what side effects you might experience.   

  • immunotherapy is a type of cancer treatment that helps your immune system find and destroy cancer  

  • immunotherapy is not used to treat all types of cancer 

  • if you have any questions about immunotherapy or about the information you’ve been given you should speak to your care team 

What is immunotherapy? 

Immunotherapy is a type of cancer treatment that helps your immune system find and destroy cancer cells. Immunotherapy is not just one type of treatment, it’s the name used for a group of treatments.  

Our immune system protects our body from infection, illness and diseases. Usually, your immune system finds and destroys cells that are harming you, but cancer cells can sometimes get around it and keep growing. This might be because the cancer cells aren’t noticed by the immune system or because the immune system isn’t strong enough to destroy them.  

How does immunotherapy work? 

There are different types of immunotherapy which work in different ways.  

Some kinds of immunotherapy, like monoclonal antibodies, work by finding specific proteins on cancer cells or immune system cells, and they work in different ways depending on the protein they’re looking for.  

Checkpoint inhibitors work by blocking proteins that stop the immune system from destroying cancer cells. If you imagine the cancer cells hiding behind a rock so the immune system can’t find them, checkpoint inhibitors allow the immune system to find the cancer, take away the rock and attack the cancer.  

CAR T-cell therapy is a type of immunotherapy used to treat certain blood cancers, which makes your own white blood cells (also called T-cells) better at finding and destroying cancer cells.  

There are also proteins called cytokines which scientists have developed man-made versions of, that can be used to treat some types of cancer.  

When you’re told you’ll be having immunotherapy you should be given written information to help you understand. If you have any questions about immunotherapy or about the information you’ve been given you should speak to your care team and they’ll be able to help you.  

What are the side effects of immunotherapy?  

Everyone is different and people will experience different types and levels of side effects. It’s important to contact your care team if you feel different in any way.  


Immunotherapy can cause inflammation in any part of the body. Inflammation is the body’s reaction to injury or infection. You might see a visible change, like a rash, where your skin might become swollen, painful, itchy or more red than usual.  

Sometimes the inflammation might happen inside your body - you can’t see it but you might notice the effects. For example, if you have inflammation in your bowel (which helps your body digest food), you might get diarrhoea. 

Inflammation might also make you feel a bit strange or ill but you may not be able to tell why. It’s really important to know how you feel normally (also called your ‘baseline’) so that you can tell your care team if anything feels different. Even if you just feel a bit unwell, you should contact your care team straight away so they can decide on the best next steps. 

Your care team will need to understand where the inflammation is coming from, so usually you’ll be asked not to take any new medication (like anti-diarrhoea medication) until you’ve spoken to them. This is because it might make it difficult for them to find out what part of your body is affected if it’s also being impacted by medication, like pain relief.  

You should keep taking any regular medication that you’re already on. 

Your care team will give you a list of phone numbers and explain who you need to contact in different situations. It’s really important that you keep these in a safe place where you can find them. It might also be helpful to share the list with someone you’re close to, so they can help you if needed.  


Another common side effect of immunotherapy is fatigue. Fatigue means feeling exhausted and having no energy. Some people experience fatigue while they are having cancer treatment or after they have finished cancer treatment as a late effect.   

Sometimes fatigue could be a side effect due to inflammation or a hormone imbalance (when you have too much or too little of certain hormones). These imbalances can be treated with medication by your care team and they will also tell you when to contact them.  

Long term and late effects 

When you finish treatment you might still have side effects. You’ll keep having check-ups to monitor any side effects, and also to look out for late effects, which can sometimes appear more than a year after treatment.  

Some people might experience lifelong effects of immunotherapy. This might mean that you have to take regular medication to help with these effects. For example, immunotherapy might impact how your thyroid works, if this happens then you’ll be given medication to help. You can always speak to your care team if you’d like to know more about long-term and late effects of immunotherapy. 

How can I manage the side effects of immunotherapy? 

Usually steroids are used to manage inflammation as a side effect of immunotherapy.  

If your side effects are spotted early, they can usually be treated quickly and you can continue with your immunotherapy treatment. If the side effects are caught later or are more significant, then your immunotherapy treatment might have to be delayed. This is because taking steroids while you’re still having treatment will temporarily impact how the immunotherapy works. Carrying on with treatment when side effects have started can also make the side effects worse.  

While the idea of delaying your immunotherapy treatment might be worrying, this doesn’t mean that the immunotherapy won’t work. You should be able to continue with your immunotherapy treatment once your care team says you can. Sometimes, if side effects are really bad and making you very unwell, you might have to stop immunotherapy completely.  

What is the difference between immunotherapy and chemotherapy? 

There are a lot of different types of cancer treatment and sometimes it can be confusing to understand the differences. Immunotherapy and chemotherapy are different treatments. Immunotherapy involves making your immune system better at targeting and destroying cancer cells whereas chemotherapy (chemo) uses drugs to kill off the cells that cause cancer.  

Chemo works by attacking and destroying fast-growing cells, and the side effects are more predictable. For example, chemo kills cancer cells but can affect other fast-growing cells like hair cells, cells that line your mouth and cells that line your stomach. While losing your hair is a common side effect of chemo it’s not a common side effect of immunotherapy because immunotherapy does not affect fast-growing cells more generally.  

Immunotherapy doesn’t suppress your immune system in the same way chemo does, so it doesn’t make your immune system weaker. While the side effects might be different, you still need to contact your care team as soon as possible if you notice any changes. 

You can find out more about chemo here.  

Where will I have immunotherapy? 

Most of the time you will have immunotherapy in a clinic or hospital. There are some areas of the UK where there may be an option to receive some of your treatments at home. You’ll be told if this is an option for you.  

Why have I been offered immunotherapy? 

Immunotherapy isn’t  suitable for all types of cancer. Whether you are offered immunotherapy or not depends on the type of cancer you have, how far it has spread (the stage of the cancer) and other factors. Sometimes you need to have some tests to decide if the treatment is likely to work. Immunotherapy can also sometimes be used in combination with other treatments, like chemotherapy, depending on the type of cancer. 

How will I be given immunotherapy? 

Immunotherapy is generally given to you through an IV, or by an injection with a needle. Your care team will explain to you how you will have your treatment. 

Before each treatment, you’ll also have a blood test which looks for any inflammation inside your body.   

What impact will immunotherapy have on my fertility?  

Immunotherapy may affect your fertility. If you have any questions or concerns about your fertility, talk to your care team.  

It’s important to let them know if you think you might be pregnant as this might affect your treatment. You should use contraception if you’re having sex while having immunotherapy to avoid getting pregnant during treatment.  

You can find out more about how cancer treatment can affect your fertility, and fertility preservation options here.  

Questions to ask about immunotherapy

It’s OK if you don’t understand everything in your first appointment. Once you’ve had a chance to think through everything you’ve been told, you can ask any questions you have. You might want to ask someone in your care team for a phone call or another appointment to go through your questions, if you have a lot. Here’s some questions that might be helpful: 

  • how often is my treatment? 

  • what’s the name of my medication? 

  • what kind of immunotherapy am I having? 

  • what side effects should I look out for? 

  • who do I need to ring if I think I’m having side effects? 

  • are there any support groups specific to the kind of cancer I have? 

  • can someone come with me? 

  • will I be able to work during treatment? 

  • can I do exercise during treatment? 

  • will I be able to go on holiday?