CHICAGO: A highly sensitive microchip may help doctors detect rare traces of cancer circulating in the bloodstream, offering a way to better manage treatment, US researchers said on Wednesday.

The device can isolate, count and analyze circulating tumor cells from a blood sample, the team at Massachusetts General Hospital and Harvard Medical School in Boston said.

These circulating tumor cells, or CTCs, are the tiniest fragments of tumors, which are carried in the blood. Doctors have known about them for some time, but because they are so rare and so fragile, they have been hard to trap and study in a meaningful way.

"What our technology does is increase the sensitivity many, many fold, to a point where it can become a tool that can be used clinically," said Mehmet Toner, whose group developed the device. He said routine monitoring of these cells could help doctors tailor treatments to patients and may one day aid with diagnosis.