Your blood tells a story
When we hear the word ‘biopsy’, we immediately tend to think of a minor procedure in which a small piece of tissue is removed from the patient for further investigation. But a ‘liquid biopsy’ is less invasive than a surgical biopsy. In fact, a liquid biopsy usually involves just taking a blood sample, although a urine or saliva sample also falls into the same category.
Liesbet Lagae: “Cancer specialists have discovered that the blood of cancer patients differs from the blood of healthy people. As a result, oncologists are able to detect all kinds of indications in this ‘different’ blood that can help with the diagnosis and treatment of cancer.”
“For instance, they may find tumor cells in the blood that have separated from the original tumor (that may be located in the lung tissue, for example). They are called ‘circulating tumor cells’, or CTCs. Another area of interest in the blood sample is blood platelets. We now know that the blood platelets in cancer patients are different from those in someone healthy. What the tumor appears to do is use the blood platelets to help itself grow. Phospholipids in the blood also contain information about cancer. For instance, determining the profile of the phospholipids present makes it possible to discover prostate cancer in the blood.”
Just why there are all these differences between 'healthy' and 'cancer' blood is still a mystery in the main. Shedding more light on this mystery, will help cancer experts to gain a greater insight into exactly how cancer goes to work in our body.
Why use a liquid biopsy?
A liquid biopsy has several benefits in comparison with a tissue biopsy: for a start, it is less invasive for the patient and it can be carried out as often as necessary, which makes it possible to track the patient’s progress better through the treatment process. The liquid biopsy also provides a ‘live’ picture of the cancer at that specific moment and there is never a problem in terms of being able to take the biopsy (for example when the patient is too weak to undergo a tissue biopsy, or if the primary tumor is difficult to reach).
Yet despite all these advantages, liquid biopsies will never be the only technique used. That’s because cancer is a highly complex disease and for doctors to obtain a full picture of the situation, various techniques need to be used alongside each other – liquid and tissue biopsies, imaging. Liesbet Lagae: “For example, we can see that the cancer cells in the blood often have properties that differ from the cancer cells in the original tumor. The tumor may also be made up of different types of cells (called a ‘heterogeneous’ tumor). This makes the liquid biopsy a welcome and excellent new adjunct in the toolbox of cancer specialists, in addition to tissue biopsies and imaging.”