Immunotherapy

Immunotherapy is a relatively new type of lung cancer treatment. It is currently available to people with certain types of lung cancer.

What is immunotherapy?

Immunotherapy, or immune-oncology (IO) as it is sometimes referred, is a type of treatment for non-small cell lung cancer (NSCLC). It works by helping the body’s immune system to recognise and destroy cancer cells.

Cancer cells can sometimes find ways to trick the immune system into thinking they are normal cells and should not be attacked. This allows them to grow and spread. One way this happens is through proteins called checkpoint proteins.

PD-L1 and PD-1 are types of checkpoint proteins. PD-LI is found on normal tissue surface and healthy cells, while PD-1 is often found on a type of white blood cells called T-cells. Some cancers disguise themselves by making their own PD-L1. When this happens, it binds to PD-1 on T-cells.

These cells are then not spotted by the checkpoints which means the immune system does not destroy them. Undetected, the cancer cells can continue to grow without being slowed down or stopped.

Immunotherapy treatments reactivates the immune system, helping it to recognise and attack the abnormal cancer cells. Some checkpoint inhibitors work by binding or sticking to the PD-1 on T-cells or PD-L1 on tumour cells.

Immunotherapies stop PD-1 from binding to the PD-L1 on cancer cells. When this happens, the cancer cells can no longer trick the immune system.

How can I receive immunotherapy for lung cancer?

At present, there are four immunotherapies licensed and approved for use in the UK to treat people diagnosed with advanced non-small cell lung cancer, either squamous or non-squamous. These are called:

• Atezolizumab
• Durvalumab
• Nivolumab
• Pembrolizumab.

Immunotherapy is an effective treatment for some people with lung cancer, but not for others. This is because the immune system can only recognise cancer cells that have particular genetic mutations. People with Epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) mutations, for example, don’t tend to respond positively to immunotherapies.

As a result, EGFR and ALK+ lung cancer patients are offered targeted therapy and chemotherapy before immunotherapy.

In order to see if immunotherapy is a possible treatment option, doctors may order biomarker tests. If this is the case, a biopsy of your tumour will be taken and tested for the proteins PD-L1 and/or PD-1. Your doctor will then discuss your results with you to see if you have the required expression.

How is immunotherapy given?

Immunotherapies are given to you through an infusion (drip) into a vein in your arm. Alternatively, it may be given through a long plastic tube into a vein in your chest. This is known as a port-a-cath or power-port.

Frequency of treatment will differ depending on which type of immunotherapy you are on. Nivolumab, for example, is given every two weeks, while Pembrolizumab is every three weeks. Each treatment session takes approximately 90 minutes.

Why is immunotherapy only given for two years?

Like most lung cancer treatments, immunotherapy is only given for a set period of time. Immunotherapy is given for a maximum of two years. After then, it will be stopped. This can naturally be a very anxious and scary time; to have a treatment that is working seemingly taken away from you.

Immunotherapies are very new ways of treating lung cancer and the data about them is still growing.

There is some evidence from other types of cancer, such as melanoma, that stopping treatment may not stop the patient’s response to it; the immune system becomes re-programmed to better recognise cancer cells.

Side effects of immunotherapy

Immunotherapy can cause many different side effects which can worsen or fail to improve over time. However, many people on immunotherapy experience much milder symptoms than those on other lung cancer treatments, like chemotherapy.

Common side effects include:

• Fatigue
• Itching
• Skin rash
• Loss of appetite
• Cough
• Nausea
• Constipation
• Joint pain
• Diarrhoea.

Immunotherapy can sometimes cause your immune system to become too active. This may cause your body to react against normal tissues, such as your lungs, liver and colon. Your thyroid function may be affected; hypothyroidism is the commonest immune-related toxicity.

If you have any questions about immunotherapy and if it is a suitable treatment for you, speak to your healthcare team.