Man’s Best Friend: a Canine Biosensor for Cancer?

Reading time: 3 – 5 minutes

Man’s best friend may someday turn out to be a physician’s tool for the detection of several types of cancer.

NBC Nightly News aired an intriguing story last night about dogs who have the ability to detect ovarian cancer [1]. The story referenced a new study published in the European Respiratory Journal that focused on canine scent detection for the diagnosis of lung cancer [2].

The outcome of a patient with lung cancer, like many other cancers, depends in large part on early diagnosis. Exhaled breath of patients may represent the ideal lab specimen for cancer screening. However, current diagnostic sensor technologies are unable to identify a clear target. German scientists used four sniffer dogs to test the strength of the presence of an as-of-yet unknown compound in the breath of patients with lung cancer.

That as-of-yet unknown compound is a biomarker — a protein or set of proteins specific to lung cancer that, by nature of the tumor being in a patient’s lungs, is exhaled.

In the study, researchers had patients with blow into test tubes filled with a fleece material that absorbs compounds suspended in the breath. Following a rigid scientific protocol, sniffer dogs were presented with exhalation samples from either 110 healthy individuals, 60 patients with confirmed lung cancer or 50 patients with chronic obstructive pulmonary disease (COPD). The dogs were trained to lie down next to test tubes that came from patients with lung cancer. Scientists analyzed patient history, drug administration and clinicopathological data to identify potential bias or confounders.

The results are impressive. Lung cancer was identified by the four dogs with an overall sensitivity of 71% and a specificity of 93%.

Sensitivity: the proportion of samples correctly identified as positive (i.e. having lung cancer).
Specificity: the proportion of samples correctly identified as negative (i.e. not lung cancer).

The detection of lung cancer was independent of the patient having COPD as well as the presence of tobacco smoke and food odors.

Although two drugs were identified as potential cofounders — meaning the dogs may have been detecting drugs used to treat lung cancer rather than the cancer itself — the results are still intriguing. Researchers are working on a follow-up study to determine if the dogs react to other types of cancer [3].

Check out a video of the NBC News story below:

References

  1. Trained dogs can help detect cancer. NBC Nightly News. 2011 Aug 18.
  2. Ehmann et al. Canine scent detection in the diagnosis of lung cancer: Revisiting a puzzling phenomenon. Eur Respir J 2011. Published ahead of print.
  3. Fine dog noses sniff out lung cancer. Robert-Bosch-Krankenhaus. 2011 Aug 18.
About the Author

Walter Jessen is a senior writer for Highlight HEALTH Media.