Liquid biopsy, a non-invasive blood test used to detect, monitor and analyse cancers, is steadily gaining acceptance as a standard tool to assess progression and treatment in a range of cancers. Scientists Catherine Alix-Panabieres and Klaus Pantel, who coined the term “liquid biopsy” in 2010, were in Mumbai recently to meet top oncologists and unveil an indigenously developed liquid biopsy platform by Actorius Innovations. Alix-Panabieres is director, Laboratory of Rare Human Circulating Cells, University Medical Centre of Montpellier, France, and Pantel is director, Institute of Tumour Biology, University Medical Centre Hamburg-Eppendorf, Germany. They spoke with ET’s Vikas Dandekar on the growing adoption of liquid biopsy in detecting circulating tumour cells in clinical practice. Edited excerpts:How did you strike the term liquid biopsy?
Klaus Pantel: In tumour diagnosis, the routine method is to take a needle and put it into a solid tumour mass and that is called solid biopsy. How then to frame a word when we draw a blood sample or any other body fluid? So, we came up with the name liquid biopsy. We thought people may think it’s stupid. The famous science journal Nature mentioned it as one of the key discoveries of the last 20 years, and they quoted us as the mother and father of this term, liquid biopsy, in 2010.
How much have cancer treatments gained from the new method?
Catherine Alix-Panabieres: First nobody believed in detecting circulating tumour cells in the blood because it’s really a rare event, mostly seen in early stages or minimal residual disease state. It was not easy to prove that cell fragments from the tumours exist in blood. Then it was good to stimulate the scientific community to work on liquid biopsy analysis. The definition now is broad because we talk about circulating biomarkers derived from tumour cells. That means tumour cells release some specific information like DNA, RNA, EVs or extracellular vesicles and many others. These are not directly released by tumour cells, but induced like the immune system, speaking in the context of immunotherapy. It means that when you have a tumour cell, you must check what is the background of the host, and how the immunity is able to fight or counterbalance. Everybody would like to have such a test to personalise treatment or medicine and manage cancer patients. But we need to get more interventional clinical trials to prove the benefit for the patient and what clinicians can do to treat their patients better.
India has a rising cancer burden. Do you think using techniques to understand circulating tumour cells can lead to cost benefits?
Pantel: I think it will have a significant positive effect on the financial burden of the patients. First, if we detect cancer early, it can be cured and the patient can continue a normal life with a normal life expectancy. The patient can pay taxes and does not need any further treatment. I also think when we use the blood test to understand which patient needs which therapy, it is very important because then we do not use expensive therapies that do not work. We can just use expensive therapies for those patients on whom it works and that is also cost-effective. I would say that even if our test is $1,000, it would save probably $10,000 in therapy costs that are otherwise given in the wrong way. This has a strong economic impact as early detection and personalised cancer treatment will reduce costs.
If the benefits are so clear in terms of treatment and costs, why are circulating tumour cell tests and liquid biopsies not getting the due popularity?
Pantel: I guess if you want to develop a new field, it is always difficult. People who do imaging may not like our field. People that do pathology or tissue biopsy may be a bit afraid. If you come up as something new, the established fields get a little bit defensive. We need to create a new field with concerted efforts. In the European Liquid Biopsy Society, we say let’s forget for one moment that we are competitors and what we have as a common goal. We want to develop a whole field and if this field is developed, which means if it’s really used in the clinic, all of you will be happy. It’s good to have this competition because it also drives technology advances.
