New blood test detects more than 50 types of cancer

A new type of blood test that detects dozens of cancers could help doctors treat patients at an earlier stage, according to results of a study published this week. The method was used to identify more than 50 types of cancer in patients, including particularly deadly variants such as that affecting the pancreas, ovaries, intestine, and brain.

The researchers say the method is able to detect cancer mutations before symptoms appear, and also to locate particularly dangerous tumors that would otherwise go unnoticed.

The test looks for major changes in the DNA of dead cancer cells that leak into the blood, as diseased tissues break down.

In the study on the scientific finding, published in Annals of Oncology, experts acknowledge that the procedure is more suitable for detecting cancer in later stages of the disease. However, the authors claim that following their research could result in tests that diagnose cancer at a much earlier stage than with other methods.

Tracking molecules

The test, developed by the Dana-Faber Cancer Institute and the Mayo Clinic, looks for molecules known as methyl groups, which cause mutations in healthy cells and make them cancerous. It marks a change from more traditional methods involving DNA sequencing.

The research consisted of taking samples from almost 7,000 participants. In 96 percent of the tests, the samples correctly identified the tissue from which the cancer came.

More evidence is needed

"Our results show that this approach to analyzing cell-free DNA in the blood can detect a wide range of cancer types at virtually any stage of the disease, with specificity and sensitivity close to the level necessary for detection at the level of population, "said Geoffrey Oxnard, co-author of the study. "The test may be an important part of clinical trials for the early detection of cancer."

However, experts admit that more research is needed. Today, they said, the chance that tests will not detect cancer in its early stages is still too high.