Researchers in the U.S. and the U.K. have developed a new blood test to detect cancer. The test, which may revolutionize cancer diagnosis, can detect 50 different types of cancer which have not yet manifested themselves in symptoms. And it uses only a single drop of blood.

The test works by detecting “cell-free DNA” released by tumor cells. Because many non-cancer cells also release DNA into the blood, the test can detect a chemical called a “methyl group” which is associated with tumor growth. After isolating the DNA from the blood sample and sequencing it to find the methylated parts, the result is fed into a computer. This computer can then can use artificial intelligence to differentiate cancer from non-cancer cells.

The researchers’ findings were recently published in Annals of Oncology. For the study — which is part of a larger study of 15,000 people — researchers tested the blood of more than 4,000 people, roughly half of whom had cancer. The researchers included over 50 types of cancer in the study. The test was accurate in 93% of the samples. It could accurately predict where in the body the cancer first developed in 96% of the samples.

The false-positive rate was lower than that of many cancers screening tests, including those for breast cancer and colon cancer.  The test still needs to be validated in larger, population-level studies. Many of those studies are underway with results pending, but the researchers are optimistic.

A way to detect cancer earlier?

Prof. Fabrice André, editor-in-chief of Annals of Oncology, stated: “This is a landmark study and a first step toward the development of easy-to-perform screening tools. Earlier detection of more than 50% of cancers could save millions of lives every year worldwide and could dramatically reduce morbidity induced by aggressive treatments.”         

A particularly important aspect of the blood test is that it can pick up cancers that are typically very slow-growing and where symptoms only appear when the cancer is most dangerous, such as pancreatic, lung, and ovarian cancers. These cancers account for over 60% of all cancer-related deaths every year in the U.S.  

Read the study here: Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA

Read some of our other coverage of cancer diagnosis and treatment.