Oxford Medical Oncologist, Dr Mark Tuthill specialises in immunotherapy cancer treatments, and here he explains how these medications work and their side effects.
What is the immune system?
The immune system defends the body against infections. It includes white blood cells and antibodies which can attack, incapacitate and destroy certain bacteria, viruses and abnormal cells such as cancer cells. Cancer cells arise from changes in the genetic code of a cell. These changes are called mutations. The changes in the genetic code can also lead to changes in the physical characteristics and behaviour of cells compared to normal healthy cells. Cancer cells that continue to grow will form tumours.
How does immunotherapy work?
The body’s immune system is often able to detect cancer cells and destroy them. However, in certain circumstances, cancer cells remain undetected by the immune system. Some cancer cells have a coating on the cell surface which shields the cancer cells from attacks by the body’s immune system. This enables the cancer cells to continue growing into a tumour even in the presence of a healthy immune system. Recently, scientists have developed medical treatments which can prevent cancer cells from hiding from the immune system.
What are checkpoint inhibitors?
The commonest and most widely used immunotherapy medications are called immune checkpoint inhibitors. These immune checkpoint inhibitors re-energise your immune system and allow it to see and attack the cancer cells. Examples of checkpoint inhibitors are Nivolumab, Pembrolizumab, Atezolizumab and Ipilimumab. These medicines are given intravenously via a drip into the arm.
Immune checkpoint inhibitors can be used to treat a wide variety of types of cancer, including those of the breast, bladder, kidney, lung, skin and many other forms of cancer.
Other forms of immunotherapy treatments and research
Cancer vaccines and immune cell treatment therapies, which use modified versions of your own immune system to attack the cancer cells. If you are interested in taking part in a research trial, please ask your cancer specialist to consider you for a trial or refer you to a specialist centre which has a suitable study open.
How are these medications taken and how often?
All immunotherapy medications are given intravenously every two to six weeks. They are given on an on-going basis if the tumour has responded to treatment. In certain cases, these medications have enabled some people to have a normal life expectancy after treatment, even for patients diagnosed with some forms of advanced cancers.
Are there any side effects of taking these drugs?
Immunotherapy is much better tolerated than chemotherapy. Most patients feel nearly normal during treatment and studies have shown that the quality of life is better for patients having immunotherapy rather than chemotherapy. The commonest side effects are tiredness, itching, skin rash and diarrhoea. A full list of the side effects will be provided when the treatment is discussed with you, including a detailed explanation of when the side effects may develop and the treatment for the side effects.
How long do you have to take these drugs for?
The usual recommendation is for as long as the treatment appears to be working. However, some treatments may be limited to up to two years.
What is the success rate of immunotherapy?
Immunotherapy has been proven to make patients live longer as many types of cancer are responsive to the treatment. The response rates vary between different types of cancer. Your oncologist will be able to explain this to you in more details when you discuss immunotherapy treatment with them.
When are the results felt and how are they monitored?
If the immunotherapy treatment is effective, there will often be a shrinkage of cancer on scans. Your oncologist will monitor the effectiveness of the immunotherapy by arranging for you to have regular scans and check-ups to ensure the treatment remains effective and to monitor you for side effects.
Immunotherapy treatments have revolutionised the treatment of many different types of cancer, including cancers of the breast, lung, bladder, kidney, skin, head and neck, lymphoma and many other types of cancer. If you are interested in immunotherapy for the treatment of cancer, ask your oncologist. If a form of immunotherapy is not available for your condition as a standard treatment, you can ask if you can take part in a clinical trial of a new medication.
Do not hesitate to book an appointment with Mr Tuthill if you're researching your cancer treatment options.