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Lung Cancer Successfully Diagnosed By Beagles Sense Of Smell

Lung cancer is the second most common cancer diagnosed among patients in the United States. This type of cancer is also responsible for the largest number of cancer-related deaths.
With lung cancer, early diagnosis is critical. Currently, the most common methods of diagnosing lung cancer are through CT and PET scans. These diagnostics are very costly and can sometimes be inaccurate or unreliable.
A recent study reported that beagles, who have a very sensitive sense of smell, can “sniff” out lung cancer with a very high degree of accuracy.   

lung cancer



Lung Cancer: Detecting Disease Through Smell

As current diagnostic tools used detect cancer of the lungs can at times be inaccurate, researchers are looking for better tools. The smell acuity of dogs and beagles in particular is very sensitive.


The olfactory acuity of a dog is at least 10,000 times more sensitive than that of a human. This may be due to their larger olfactory lobe and greater number of smell receptors. Indeed, the differences are incredible. Beagles have 225 million olfactory receptors. In comparison, humans have 5 million olfactory receptors.

Beagles are also able to retain air in their nasal passages for longer periods of time during exhalation. This helps them identify odors.

Lung Cancer: Results of Cancer Detection By Beagles 

The research team worked with three beagles, whom they trained to “sniff out” lung cancer cells in plasma (blood) samples. They specifically chose beagles because they are scent hounds  — traditionally bred to chase small game animals during a hunt.


Beagles were trained for 8 weeks. After the training period, the beagles were required to correctly distinguish between blood samples collected from individuals with non-small cell lung cancer. They also sniffed a set of blood samples from healthy individuals.


All samples were placed in one room, at a height at which the dogs could comfortably sniff them. The beagles were trained to sit down when they could smell cancer, or move away if the sample was from a healthy person.


Incredibly, The dogs successfully chose between the two samples. They identified the presence of cancer with 97.5% specificity, and 96.7% sensitivity.

At present, researchers are completing a study testing the dogs’ ability to identify several other forms of cancer, including breast cancer and colorectal cancer.

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