How close are blood tests for cancer to widespread deployment for screening? Elizabeth Tracey reports


Simply analyzing a blood test to screen for cancer is becoming closer to reality as many more assays come online, with a new one improving lung cancer detection by about 9% when used with CT scanning. William Nelson, director of the Kimmel Cancer Center at Johns Hopkins, says their underlying strategy is simple.

Nelson: Many of them are from the turnover of cancer cells in the body, DNA, RNA, protein and things in them, they swim around for some period of time and give you a chance to build detection strategies that scientists will call assays. The ideal test will have a high positive predictive value, that’s when the test is positive you have a high chance of having the condition, and also have a high negative predictive value, so if they say it doesn’t seem to be a problem you really can sleep easier as opposed to maybe they missed something.  :30

Nelson says current screening methods often identify possible cancers that turn out to be benign and miss a certain number, and blood testing may improve that. At Johns Hopkins, I’m Elizabeth Tracey.