Targeted therapy

Tumours need a blood supply to survive. Without a good blood supply, the tumour does not get the oxygen and nutrients it needs. This may slow the tumour’s growth, or sometimes cause it to shrink.

Angiogenesis inhibitors block the chemical signals that cells use to make blood vessels grow. This makes it difficult for a tumour to develop the network of blood vessels it needs to get a blood supply.

All cells have receptors on their surface. Receptors help cells send or receive signals. A receptor is a bit like a lock. Only the right key fits the lock. Another cell or substance can only connect to the receptor if it is the right fit.

Monoclonal antibodies are made so they can only connect to one type of receptor. Most monoclonal antibodies target receptors that are mainly found on cancer cells. Some target receptors that are found on other cells in the body.

By connecting to the cell’s receptor, a monoclonal antibody could:

• block signals that tell cancer cells to grow and divide (also called a cancer growth inhibitor)
• block signals that help cancer cells develop a blood supply (also called an angiogenesis inhibitor)
• block signals that stop white blood cells attacking cancer cells (also called a checkpoint inhibitor)
• help the immune system recognise cancer cells (also called an immunotherapy)
• block signals to protect the bones from damage causes by some types of cancer or cancer treatments – for example, denosumab (Xgeva^®, Prolia^®)
• carry a chemotherapy drug straight to the cancer cell.

A monoclonal antibody may also carry radiation directly to the cancer cell. This treatment is not widely used and may only be available as part of a research trial (clinical trial).

Before you have targeted therapy, you might have tests to find out if the treatment is likely to work for you.

The tests may check whether the cancer cells have a certain type of receptor for a monoclonal antibody to target.

You may have tests to look for genetic changes in your cancer cells. These include testing for HRD before PARP inhibitor treatment.

Doctors may check the cancer cells using a blood test, or by taking a sample of tissue (a biopsy). If you have had an operation, they may already have a sample of your tissue they can test. This kind of testing is not needed for all targeted therapies. If you need these tests, your doctor or nurse can tell you more.