Q: Another approach used in MCED tests is based on analyzing the size of DNA fragments in the blood. Can you explain how this works?
Dr. Delaloge: When cancer is not present, the size of DNA fragments in cells is much more homogeneous. Here also, the benefit of MCED based on this technique rests on the very early detection of cancers that are less common than those for which we already have good screening methods available.
Other approaches, still at the experimental stage, detect certain proteins, certain inflammatory molecules, RNA, etc. But for many researchers, the future will involve pairing tests on the basis of circulating DNA in the blood with the detection of specific molecules indicating the presence of cancer to obtain early screening tests that are even more effective or that possibly even allow us to identify an appropriate treatment at an early stage.
The development of a simple test based on a blood draw that allows us to screen early for all cancers and that would replace all current screening measures is, therefore, not imminent, although it could potentially be on the horizon in years to come. Alongside this, an important issue is the benefit of cancer screening in the general population vs. in a targeted population with a specific risk. The latter option is in development but requires an individualized screening pathway based on blood testing and current screening methods: imaging, etc. It also depends on an individual’s cancer risk profile such as age, personal and family medical history, genetic predisposition, and so on.
According to recent modeling, these multicancer tests could theoretically prevent a minimum of 2,000 deaths from cancer per 100,000 people between ages 50 and 79 years screened per year (17% fewer deaths from cancer per year).
This article was translated from the Medscape French Edition. A version appeared on Medscape.com.