It is a treatment which helps our immune system to combat cancer. It enables our system to recognise and attack the cancer.

The immune system defends the body against any type of attack.
 
When tumour cells develop, our immune system should identify them as foreign bodies and respond by activating and producing T lymphocytes to neutralise or eliminate these abnormal cells.
 
The problem is that the tumour releases a series of substances (PD-L1) which block the immune system (PD1 receptors) and the lymphocytes become inactive. As a result the cancer cells are not recognised as foreign.
 
Immunotherapy unblocks this action. The immune system recovers its defensive capability and the body therefore destroys the cells.
 

• They act on lymphocyte receptors and tumour cells.

 

• They prevent the tumour from paralysing the lymphocytes, allowing them to act as destructive elements.

 

• The immune system recovers the capacity to recognise and attack the tumour.

In the majority of cases it is a well-tolerated treatment with little toxicity.
 
Immunotoxicity can develop when stimulating the immune system, it can include:
 
Diseases related to the immune system, all of which involve inflammation: dermatitis, pneumonitis, colitis, hypophysitis…
 
With stimulation of the immune system, immune-mediated toxicity can manifest as:
 

• Skin breakouts or itching,
• Diarrhoea,
• Liver inflammation,
• Lung inflammation,
• Hormonal abnormalities,
• Muscle pain,
• Shortness of breath,
• Swollen legs (oedema),
• Paranasal sinus congestion,
• Headache…

It is very effective in some cancers and in some patients.
 
The action of immunotherapy drugs on some cancers, such as lung and melanoma, has already altered prognosis of the disease, proving to be more effective than traditional therapy on some occasions.

More and more cancers can be treated including: lung, kidney and bladder as well as subtypes of both breast and colorectal cancer.
 
There are indicators which can help us to understand sensitivity to immunotherapy treatment:
 

• PDL1- we measure the amount of PDL1 the tumour has, the effect of immunotherapy will vary depending on the percentage present.

 

• Microsatellite instability This is an abnormality in the DNA repair proteins involved in the solution of errors during cell division or cell growth.