Immunotherapy and cancer: how does it work?
The body’s immune system is often able to detect cancer cells and destroy them, however, in certain circumstances, these cells can go undetected. This enables them to continually grow into a tumour. We’ve asked consultant medical oncologist Dr Mark Tuthill to explain how medical therapies known as immunotherapy work in treating certain forms of cancer.
What is immunotherapy?
Immunotherapy treatments for cancer are medical therapies that help a person's own immune system attack or fight cancer that they have unfortunately got. All of us have a variety of immune cells in our body, which can detect problems like infections but they can also pick up significant problems like cancer.
The problem in the past has always been that although the immune system has been able to detect cancer, it's always had difficulty destroying established tumours and these are the tumours that your doctor would have picked up.
Immunotherapy treatments stimulate your own immune system to get past these initial blocks and attack the cancer cells. This can lead to the eradication of advanced tumours and also prevents tumours from coming back.
How do immunotherapy medications work?
Immunotherapy therapy medications work in two distinct ways. The first is: they can stimulate your immune system to attack cancer that it's not seen before. So, an example of that would be a vaccine.
Other immunotherapy treatments work by essentially removing the sort of ‘molecular camouflage’ that the tumours use to hide from the immune system. An example of that would be an immune checkpoint inhibitor.
Immune checkpoints are like 'brakes' that stop the immune cells from attacking cancer cells and when we take the brakes off using medicine such as an antibody, it can stimulate the immune system to attack the cancer cells.
Once that process has been started, the immune system works a little bit like a cascade and more and more immune cells get recruited and essentially the fight is on between the tumour and the immune system.
Actually, as a result of these, the effect of ‘stimulating’ the immune system, means that the tumours can be controlled and even cured in some groups of patients.