Scientists are developing a breath test for of lung cancer, which they hope will help them detect the all to often deadly disease in time to cure it.

Researchers at the University of Louisville say they have discovered a “signature” in the exhaled breaths of lung cancer patients, which can be used to monitor the disease for recurrence – and hopefully detect it earlier as well.

Lung cancer is the leading cause of cancer death. More than 224,000 Americans will be diagnosed with lung cancer this year, and more than 158,000 lung cancer patients will die, which translates to 433 lung cancer deaths per day in the U.S., the American Cancer Society says.

Exhaled breath contains thousands of volatile organic compounds (VOCs) that vary in composition and pattern depending on a person’s health status. A subset of four VOCs—called carbonyl compounds because of their carbon base—have been discovered in the exhaled breath of lung cancer patients, the researchers say.

The team analyzed breath samples collected before and after surgery from 31 lung cancer patients and compared their carbonyl VOCs levels with samples from 187 healthy patients.

The researchers found a significant decrease in overall carbonyl VOC levels following surgery; in fact, three of the four carbonyl VOCs normalized after surgery, matching levels in the control group. They believe the rapid normalization of these compounds provides strong evidence this is occuring because of the presence of a tumor, the researchers say.

“We hope that breath analysis will allow us to diagnose patients with primary or recurrent lung cancer long before they suffer from symptoms, when we have more options for treating them, giving them the best chance for cure,” says Dr. Eric Schumer, lead author of the study, which appears in the Annals of Thoracic Surgery.