Being able to detect hints of cancer within blood samples could help identify patients in the early stages of disease, but Buzzfeed News writes that amassing the data needed to prove such an ability will take time.
BuzzFeed notes that companies like Freenome, Grail, and Guardant Health have raised millions and even billions to do just that. However, it adds that none have yet published any results showing that liquid biopsy tests can detect cancer prior to a patient exhibiting symptoms. Still, the hope is that early detection will lead to higher cure rates.
There are a number of challenges to overcome to be able to do that, it adds. Researchers tell it that concentrations of tumor-produced DNA are often low within blood samples, differences between benign and harmful changes have to be known, and variations between and within people have to be accounted for. Additionally, showing that it works in people will take years, it says.
"You have to test thousands of patients, wait long enough that enough of them get cancer and enough of them ultimately die of the disease, to be able to really evaluate if a new test is a useful screening test," Stanford's Max Diehn, who is also a Roche consultant, adds at Buzzfeed.