mind & bodyanalysisThe Conversation (US)

New blood test claims to detect 50-plus cancers before symptoms – but there’s no evidence it can reduce your risk of dying from cancer

the gist

The Galleri blood test, made by the biotech company GRAIL, claims to screen for more than 50 cancers at once in a single blood draw before symptoms appear. It sounds like a breakthrough, since cancer is widely feared, accounts for more years of potential life lost than heart disease and is increasingly striking younger people. But a physician who helps devise screening guidelines for the American Cancer Society points out that there is no evidence it reduces the risk of dying from cancer. A blood test may be safe, but its results can lead to anxiety, follow-up scans and biopsies, and overtreatment.

so what

A screening test is valuable only if finding cancer earlier saves lives, and that has to be shown in trials, not assumed.

fun fact

Heart disease, not cancer, is the leading cause of death in the United States.