Cancer is a scourge as old as life, but progress in research has led to a better understanding of this disease, which causes nearly 10 million deaths a year worldwide. We now know that for the same organ, there is no ” and “, more ” of the » cancer. And that for the same type of cancer, there can be different tumors. There are, for example, three main types of breast cancer, which are not receptive to the same treatments.
Previously, chemotherapy was often the only treatment offered. However, by aiming to eliminate cancer cells, regardless of their location in the human body, it might cause side effects.
In the 2000s, a biological understanding of the disease allowed the emergence of targeted therapies, targeting a specific genetic mutation. Over the past ten years, immunotherapy has emerged as the most important progress in oncology. The principle: the patient becomes his own medicine. Unlike chemotherapy, we no longer target the cancer cells themselves, but the immune cells that surround them, in order to activate them. Reboosted, it is the latter that destroy the tumor cells.
This discovery won the 2018 Nobel Prize in Physiology and Medicine for James Allison of the University of Texas and Tasuku Honjo of Kyoto University.
For some cancers, this discovery was major. For example, before 2010, the survival rate for patients with metastatic melanoma (the most serious skin cancer) was very low. Thanks to immunotherapy, life expectancy has increased by up to ten years, compared to a few months previously. But not all tumors respond to this treatment, which can also cause side effects.
Another pillar on which to rely: the development of Artificial Intelligence (AI), which already allows a better definition of the prognosis of cancer. Breast cancer pioneered the use of AI (when interpreting x-ray images), which is now to benefit other cancers.
A simple blood test
Another hope lies in the ability to detect a tumor very early in the body: the ” liquid biopsy “. This is a simple blood test to identify very early in the blood of a patient fragments of DNA from the tumor or cancer cells.
This technique has considerable advantages, in particular it is much less invasive than a conventional biopsy, which takes tissues from the body. For certain cancers such as those of the lung, where the tumors are often difficult to access, this is a real breakthrough.
Above all, liquid biopsy contains very precise information on a patient’s cancer by detecting mutations for certain types of cancer, and thus adapts treatments accordingly. In the future, the analysis of a patient’s blood may, in many cases, make it possible to administer lighter or shorter treatments, but also detect possible recurrences.
Several teams and biotechs are working on it around the world. The idea: to be able to detect a tumor in an individual by taking a blood sample, even before symptoms appear or it is visible on an X-ray.
Recently, the results of a study by the American biotech Grail have been particularly noticed. In their trial, a blood test made it possible to detect cancers on individuals aged 50 and over who were a priori healthy. More than 6,600 people took the test. There was a suspicion of cancer for 92 of them. In the end, 35 actually had confirmed cancer during the year and 57 people therefore mistakenly believed that they had one. But the test made it possible to detect 9 cancers which would probably not have been detected by early conventional screening.
The results are however very mixed, and it will probably take years to improve the reliability of these tests, which are already marketed in the United States. And, even reliable, these tests will still raise certain questions, warns François-Clément Bidard, oncologist at the Curie Institute (France). ” One of them is the cost, this type of sequencing being extremely expensive. Another subject is the possible over-diagnosis induced by these tests, because a certain number of cancers detected have, in fact, an extremely slow evolution and do not necessarily call for treatment. “, he explains. It will also be necessary to prove that these tests represent a notable progress compared to those which are in force today.
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