Human blood is rich with genetic material, and scientists have in recent years taken many steps forward in decoding it. The latest announcement—that a blood test can spot cancer at its earliest stages—has the potential to save millions of lives as treatment is administered earlier in the disease's progression, reports Reuters. Reporting in the journal Science Translational Medicine, scientists say that by analyzing DNA fragments in blood to look for several dozen cancer-driver genes, they spotted 86 out of 138 stage 1 and stage 2 cancers; they also confirmed no trace of cancer in 44 healthy patients (in other words, there were zero false positives). Some call this minimally invasive test a "liquid biopsy."
"This is one of the first studies that has looked directly at early-stage cancers," says lead author Dr. Victor Velculescu, an oncologist at Johns Hopkins Kimmel Cancer Center. While the test is proof-of-concept and not yet ready for prime time, detecting 62% of cancers that were only in stages 1 or 2 is a major milestone, experts say. For instance, less than one in five ovarian cancers are caught that early, when the survival rate is higher than 90%; those that are caught after the cancer has spread face a dramatically lower 40% survival rate five years out, per HealthDay News. For this study, however, the blood test caught early-stage ovarian cancer 68% of the time. Scientists hope they can get the test much closer to a 100% detection rate. (This cancer treatment is being hailed as the most exciting in a lifetime.)