Identifying cancer in a few milliliters of blood, thanks to small strands of tumor DNA, abnormal DNA strands circulating in the body, is a track that scientists have been exploring for several years.
A study, presented at the European Cancer Congress in Paris, is particularly encouraging: with a simple blood test and a test (called MCED) developed in the United States, it was possible to detect cases of cancer in adults over 50 years old, who were all a priori in good health.
In detail, 6,621 volunteers accepted the blood test. The blood test came back positive for 92 of them, making a suspicion of cancer for 1.5% of the group. And finally, after verification, cancer was confirmed in 35 of these volunteers. However, with this blood test, some volunteers may have mistakenly believed that they were developing cancer: this is the big limit of this blood test currently, which displays, for the moment, 60% false positives. In this trial, 57 patients were unnecessarily stressed and mistakenly believed for a few weeks that they had cancer.
According to Professor Fabrice André, oncologist, research director at the Gustave Roussy Institute, it will take another 5 to 10 years to improve the reliability of the test, but this study opens the beginning of a new scientific story, he says. Because this blood test still made it possible to discover 35 silent cancers on different organs. And, among them, 26 could not have been detected early by standard screening, in particular medical imaging.
In theory, about fifty cancers are potentially detectable by blood testBut these blood tests are not intended to replace existing screenings, such as those for colon or breast cancer. The idea would rather be to use them in a targeted way to screen for cancers with poor prognoses, such as that of the pancreas, for example, which is often detected too late. Because with early treatment, doctors hope to increase the survival of these patients.