Johnson & Johnson "Liquid Biopsy" Cancer Blood Test: What It Would Mean for Patients

(CBS/AP) A revolution in cancer care may be in the offing, thanks to a new blood test said to be so sensitive it can spot a single cancer cell lurking among a billion healthy ones.

The Boston-based scientists who invented the experimental test and health-care giant Johnson & Johnson were scheduled to announce today that they are joining forces to bring the test to market.

"This is like a liquid biopsy" that avoids painful tissue sampling and may give a better way to monitor patients than periodic imaging scans, said Dr. Daniel Haber, chief of Massachusetts General Hospital's cancer center and one of the test's inventors.

The test could transform care for several types of cancer, including breast, prostate, colon, and lung. Initially, doctors want to use it to try to predict what treatments would be best for each patient's tumor and find out quickly if they are working. The ultimate goal is to substitute the test for mammograms, colonoscopies and other less-than-ideal methods used now.

Doctors typically give a drug or radiation treatment and then do a CT scan two months later to look for tumor shrinkage. Some patients only live long enough to try one or two treatments, so a test that can gauge success sooner, by looking at cancer cells in the blood, could give patients more options.

"If you could find out quickly, 'this drug is working, stay on it,' or 'this drug is not working, try something else,' that would be huge," Haber said.

The test uses a microchip that resembles a lab slide covered in 78,000 tiny posts, like bristles on a brush. The posts are coated with antibodies that bind to tumor cells. When blood is forced across the chip, cells ping off the posts like balls in a pinball machine. The cancer cells stick, and stains make them glow so researchers can count and capture them for study.

For doctors who treat breast cancer, the dream is "a woman comes in for her mammogram and gets a tube of blood drawn" so doctors can look for cancer cells in her blood as well as tumors on the imaging exam, said Dr. Minetta Liu, a breast cancer specialist at Georgetown University's Lombardi Comprehensive Cancer Center.

That's still far off, but Mass General's test already is letting doctors monitor patients without painful biopsies. Like Greg Vrettos, who suffered a collapsed lung from a biopsy in 2004, when he was diagnosed with lung cancer.

"It had spread to both lungs and they couldn't operate," said Vrettos, 63, a nonsmoker and retired electrical engineer from Durham, N.H. Tests from the biopsy showed that he was a good candidate for the drug Iressa, which he has taken ever since. He goes to Boston every three months for CT scans and the blood test.

"They could look at the number of cancer cells and see that it dropped over time. It corresponded with what the scans were showing," Vrettos said of doctors looking at his blood tests.

"I think it's going to be revolutionary," he said of the test.