Sniffing out cancer.

A clinic in California claims that it has trained five dogs to detect lung cancer in patients' breath samples with 99 percent accuracy. The Pine Street Foundation in San Anselmo borrowed the dogs from their owners and Guide Dogs for the Blind and trained them like bomb-sniffing dogs: The canines would get a treat whenever they found the desired smell. Then, breath samples taken from cancer patients and healthy people were placed in plastic containers and presented to the dogs. If a dog smelled cancer, it would sit. The dogs sat correctly 564 times and did not sit 10 times for breath from cancer patients. For samples from healthy people, they did not sit 708 times and sat 4 times. Some experts said that smells from chemotherapy or smoking might have clued in the dogs. But Michael McCulloch, the lead researcher, says patients on chemotherapy were excluded and there were smokers in both groups. The next step is to repeat the study with other dogs and do chemical analysis of the breath samples. "It's biologically plausible," says Dr. Ted Gansler of the American Cancer Society. "But there has to be a lot more study and confirmation of effectiveness."