Cancer prevention, screening and treatment are evolving quickly. Oncologists from around the world, gathered at ASCO 2018, speak a new language whose expressions quickly reach the language of patients. Why Doctor shares with you these new words of cancer. Today: the liquid biopsy.
Interview with Professor Frédérique Penault-Llorca, General Director of the Jean-Perrin Center in Clermont-Ferrand and Deputy President of Unicancer.
Dr. Jean-François Lemoine: The word "biopsy" is not very new?
Pr Penault-Llorca Biopsy is removing a small piece of the cancerous tumor for analysis. That is, it's not the whole tumor, just a fragment. In general, either to make a diagnosis, or to a secondary lesion, or before operating someone.
Dr. Jean-François Lemoine: It is understandable that going for a tumor in the liver, it is quite simple, but when it comes to get the tumor inside a lung problem. What do we do ?
Pr Penault-Llorca: It is indeed an act that is called "invasive". That is, one enters the body to remove a tumor fragment. In some cases, we have to do it under scanner or MRI. Sometimes with general anesthesia; there is a risk of hemorrhage ... It is therefore a heavy act. The parade today is what is called liquid biopsy. It is a simple blood test, which we will treat in a particular way. In this blood test, we will look for small pieces of the tumor's DNA, and analyze them, as if we were analyzing a piece of this tumor without having to take a sample.
Dr. Jean-François Lemoine: Why do not we talk about a "blood test" simply? Does medicine like to complicate to the extreme?
Pr Penault-Llorca: The technique is indeed a blood test. But the blood tests, usually, are made to look at blood sugar, blood cells, etc ... Here we do not do the same analysis, we do not treat the blood sample the same way. We are looking specifically at the DNA of the tumor circulating in the blood. And this DNA of the tumor, which walks in the blood, will allow us to tell us that there are tumors, we do not necessarily know where ... It allows to follow the evolution, to quantify the tumor mass that is present, and probably the most interesting today, in the limit of technologies that we have, to analyze these characteristics, without having to take, to repeat biopsies. It's a huge plus for patients ...
Dr. Jean-François Lemoine: We could dream a little by telling ourselves that with a blood test we could prevent! And to say to someone who is well: "be careful, you have a tumor that does not speak yet, but is present".
Pr Penault-Llorca: Today, not yet. But I hope that one day, it will be the case and that we will be able to anticipate for example in people at very high risk of cancer, smokers, or people who have a genetic risk ... the occurrence of their cancer thanks to these samples. But today, the tests are not yet sensitive enough, we may not yet know exactly what to look for. So we are going to say that today, it is not yet the case.
Dr. Jean-François Lemoine: Today, of course, but when?
Pr Penault-Llorca: For me, in 5 to 10 years.
Dr. Jean-François Lemoine: It's still not in a very long time! So, if I summarize, we still do not know how to say, "be careful, there is cancer coming". But rather, "there is a cancer that is there". The results of this liquid biopsy, what are the numbers? And can we quantify the evolution of this cancer?
Pr Penault-Llorca: For the moment we do not detect cancers. This biopsy is performed on patients who have known cancers, and who are in advanced stages, with metastases. So the liquid biopsy will help us to follow this metastasis, to actually look at whether there is progression, if we see an increase in DNA, and especially if this DNA changes, which could indicate resistance to treatment that we are doing.
Dr. Jean-François Lemoine: Let's talk about this factor that seems essential: you can say, predict the effectiveness of a treatment?
Pr Penault-Llorca: Exactly. This is not science fiction! Liquid biopsies are now used in lung cancer. Some lung cancers that are treated with drugs that are called anti-EGFR. Normally, the circulating tumor DNA must decrease or even disappear. But it can also reappear, showing progression, and in some cases, mutations appear, so a change in this DNA shows that the tumor is becoming resistant to the drug.
Dr. Jean-François Lemoine: So we have to stop treatment ...?
Pr Penault-Llorca: Yes, and give another one.
Dr. Jean-François Lemoine: Can we say one day - in the same way that we can predict, but it may seem simpler - that there is no more circulating DNA, so we are cured ?
Pr Penault-Llorca: Yes, but within the limit of sensitivity. That is, today a liquid biopsy is of value if it is positive, if one identifies circulating tumor DNA. But you should know that some tumors diffuse very little circulating tumor DNA, and today we may not have enough sensitive techniques. But again, it's a matter of months or years. Technology is going very, very, very fast.
Dr. Jean-François Lemoine: Who in France can benefit from this major technological advance?
Pr Penault-Llorca: Today, this technique, as it is associated with drugs, has developed on the platforms of the National Cancer Institute, INCA. There are 28 in France. Since it's just a blood sample, put in a special tube, it can be done at a doctor's or a hospital's, and sent to one of those platforms that has the devices to do it. liquid biopsies.
Dr. Jean-François Lemoine: That is to say that all people who have lung cancer and who are treated with these drugs benefit from the liquid biopsy?
Pr Penault-Llorca: They can benefit but it will depend on the doctor. In the vast majority of cases, they are informed and will do the liquid biopsies to follow these patients.