New Blood Test Finds Cancer Cells

Dec. 19, 2007 -- A new cancer blood test may help doctors find cancers earlier and monitor cancer treatment.

The new blood test uses microchip technology to sift blood to search for circulating tumor cells (CTCs), which come from solid tumors and roam through the blood.

The developers of the test call it a "new and effective tool" that has "broad implications" for cancer research, detection, diagnosis, and management.

"While much work remains to be done, this approach raises the possibility of rapidly and noninvasively monitoring tumor response to treatment, allowing changes if the treatment is not effective, and the potential of early detection screening in people at increased risk for cancer," Daniel Haber, MD, says in a news release.

Haber directs the Massachusetts General Hospital Cancer Center. He worked on the study with researchers including Sunitha Nagrath, PhD, and Mehmet Toner, PhD, of Massachusetts General Hospital.

New Cancer Blood Test

CTCs are hard to find because they're rare, accounting for one in a billion in cancer patients' blood, according to the scientists who designed the CTC blood test.

"We developed a counterintuitive approach, using a tiny chip with critical geometrical features smaller than a human hair to process large volumes of blood in a very gentle and uniform manner -- almost like putting a 'hose' through a microchip," Toner says in a news release.

The scientists tested the CTC blood test on 116 cancer patients, including people with lung cancer, breast cancer, prostate cancer, pancreatic cancer, and colon cancer.

The test spotted CTCs in the blood samples from 99% of the cancer patients. The test detected CTCs even when there were only 5 CTCs in a milliliter of a patient's blood.

The test found no CTCs in blood samples from 20 healthy people.

In another experiment, the researchers used the blood test to monitor changes in CTC levels in cancer patients undergoing treatment.

"The chip seems to be highly sensitive," says Jonathan Uhr, MD, in an editorial published with the study in tomorrow's edition of Nature.

Uhr works at the University of Texas Southwestern Medical Center in Dallas.