Doctors develop test that may smell cancer

Tiny particles — way too small for a human to see or smell — float from the mouth, through a tube and into a plastic bag.

At a lab halfway across the world from Colorado, scientists will determine whether those tiny compounds have the distinct smell of lung cancer.

It's called a "smell print," and it could revolutionize the diagnosis of a disease that kills tens of thousands of Americans each year.

Instead of a body scan or a bronchoscopy — in which an instrument is inserted down the windpipe — patients eventually could blow into the cancer-detecting device during a checkup at the doctor's office.

"It's a bedside tool," said Dr. Nir Peled, an Israeli medical oncologist researching the cancer breath test at the University of Colorado Denver's medical campus in Aurora.

With earlier diagnosis, doctors could save more lives.

Lung-cancer rates are rising in the U.S., despite the fact that smoking rates are declining. Scientists are particularly puzzled about why the disease is striking more young women who have never smoked.

Each year in the United States, about 216,000 people are diagnosed with lung cancer and more than 160,000 people die of the disease.

Just 16 percent of lung cancer patients survive at least five years.

The reason is that two-thirds of patients are diagnosed after the cancer has spread to other parts of the body, such as the lymph nodes or other organs.

"If detected in the early stages, then we can start talking about a curable disease," said Dr. Fred Hirsch, another medical oncology professor at UCD. "It is our hope that this research could give us a tool for early detection."

The breath test works with one exhale.

Air flows into a tube and through an anti-bacterial filter that eliminates environmental scents, which would interfere with the results.

"I don't want to get the analysis that this patient put on in the morning Chanel No. 5," Peled said.

Then the air pushed out of the patient's upper-respiratory tract is captured in one of two plastic bags on the device. The rest of the air — expelled from deep in the lungs, where a cancerous tumor could be growing — is trapped in a second bag that expands like microwaved popcorn.

The second bag is removed from the device, and the particles inside are absorbed into a small vial, which is shipped to Israel for analysis.

Scientists at Technion — Israel Institute of Technology, where the device was invented, have a nanoparticle laboratory that "smells" the volatile organic compounds in a person's breath.

Breath tests might someday tell doctors not only whether a person has cancer but the exact type of cancer. Breast cancer, for example, has a different "smell print" than lung cancer, Peled said.

Scientists already have used dogs to sniff out the scent emitted by tumorous cells.

At the UCD lab, doctors are trapping air released from cancer cells growing in petri dishes and in mice with tumors. And they are collecting breath from 200 people — half of whom have lung cancer.

Among them is a Denver woman who recently had a cancerous tumor in her lung removed. She was diagnosed with cancer after a CT scan of her kidneys revealed a tumor in her lungs.

"It would be wonderful if they could diagnose us like that," said Barbara, who did not want her last name used because she has not told her friends about her disease. "They can have as many blows as they want from me. They told me it won't help me at all, but I want to help others."

Dr. Stephen Lam, professor of medicine at the University of British Columbia and one of the leading scientists in early cancer detection, said the work at UCD is significant but that it will take several years before doctors can use breath tests.

"If it works out the way it supposed to do, it will be a good first-step screening tool for high-risk patients," he said. "If you try to scan everyone who smokes at a certain age, you end up doing a lot of tests and scans on people who don't have cancer."