Aug. 17, 2011 -- German researchers say that highly trained dogs are able to reliably sniff out lung cancer in human breath.

In its early stages, lung cancer has few symptoms, making it difficult for doctors to catch it early, when it's still treatable.

"This is the holy grail," says Suresh S. Ramalingam, MD, associate professor and director of the lung program at Emory University's Winship Cancer Institute in Atlanta.

"The whole field is focused on using something that's readily available that does not involve an expensive surgery or scan that would allow us to find early cancers," says Ramalingam, who is developing technology that aims to replicate the ability of dogs to smell trace amount of chemicals produced by cancerous tumors. He was not involved in the research.

Recently a large, government-funded study found that longtime smokers at high risk for lung cancer who received annual rapid computed tomography (CT) scans of their lungs cut their risk of dying of the disease by 20%.

But that test has caused controversy because it falsely detects cancer in about one out of four people, leading to further invasive procedures.