Experimental blood test detects 8 common cancers

Overall, the test identified 70 percent of the cancers correctly.

"So, it's very promising," Bergquist says. "But this was in people who already had the cancer, and they're going to have a higher amount of the circulating tumor DNA and circulating tumor markers than in healthy people. So the next question is, if you took healthy people and tried to use the same blood test to screen this in healthy people for early diagnosis of cancer, are the numbers going to be as promising?"

It's a simple, but powerful idea: you go in for a checkup, get a quick blood test, and find out if you have one of 8 common cancers before the disease has a chance to spread.

The non-invasive test, known as CancerSEEK, is still experimental, but Emory internist Dr. Sharon Bergquist says the potential is huge.

"I think it would be very exciting to have a way of catching cancer at an earlier stage," Dr. Bergquist says. "I think it would be a big step in winning the battle over cancer."

Researchers at Johns Hopkins Kimmel School of Medicine tested CancerSEEK in 1,005 women who had one of 8 early-stage cancers that had not yet spread.

The test is designed to detect ovarian, liver, esophageal, pancreatic, stomach, colorectal, lung and breast cancer. Those 8 cancers make up about 60% of cancer deaths in the U.S. And, Bergquist says, there is no screening test to detect 5 out of the 8 cancers included in CancerSEEK.

"Currently we wait until people have symptoms, and by the time people have symptoms, we've missed that window where we can have the greatest impact on their long-term prognosis," she says.

CancerSEEK measures tumor proteins and traces of cancer DNA in the bloodstream.