Rethinking Healthcare

Dogs sniff out early-stage lung cancer

Posting in Cancer

Two German shepherds, a Lab and an Aussie shepherd smell 220 people's breaths. And they identified lung cancer reliably, despite tobacco smoke and food smells.

Ruh huh! Sniffer dogs could be used for the early detection of lung cancer, German scientists show.

Still the most common cause of death from cancer worldwide, lung cancer isn’t strongly associated with any symptoms, and early detection is usually by chance.

Oftentimes, the presence of cancer is linked to volatile organic compounds (VOCs) produced by tumors. However, no lung cancer-specific VOCs have ever been identified because patients aren't allowed to eat or smoke before the test, analyses take a long time, and the risk of interference is high.

So a team led by Thorsten Walles of Schillerhoehe Hospital wanted to see if trained sniffer dogs could identify a VOC in the breath of patients.

In particular, 2 German shepherds, an Australian shepherd and a Labrador were given exhaled breath specimens from 220 cancer patients, chronic obstructive pulmonary disease (COPD) patients, and healthy volunteers.

The participants breathed into glass tubes filled with fleece that absorbed smells, and the dogs sniffed the tubes, sitting down in front of those they detect lung cancer in.

  • The dogs successfully identified 71% of the samples with lung cancer.
  • They correctly detected 372 samples that didn’t have lung cancer out of 400. That’s a 93% success rate... nearly no false positives!
  • The dogs even detected lung cancer independently from COPD, tobacco smoke, medication, and even food odors. (Current lab tests can’t even do this.)

First of all, these results confirm that there IS a specific marker for lung cancer separate from COPD and the rest. And second… dogs are reliable (and amazing).

Their keen sense of smell, according to Walles, detects the chemical differences between healthy people and lung cancer patients at an early stage of the disease. Only 15% of lung cancers are currently diagnosed before the disease spreads to other organs… at that point, the 5-year survival rate is 2%.

Dogs have been shown to detect colon cancer, breast cancer, melanoma, and even bombs. With this new study, canine breathalyzers not only smelled lung cancer even when a patient had recently eaten or smoked a cigarette, they also didn’t mistake other scents for cancer.

“This is a big step forward in the diagnosis of lung cancer, but we still need to precisely identify the compounds observed in the exhaled breath of patients,” Walles says. “It is unfortunate that dogs cannot communicate the biochemistry of the scent of cancer!”

Once they figure out the chemical the dogs are detecting, researchers can develop a screening method. Some are already working on ‘electronic noses’ that would be able to detect the same chemical as dogs.

The study was published in the European Respiratory Journal.

Via BBC, European Lung Foundation.

Image by xandert via morgueFile

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Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure