Cancer Sniffing Dogs

From Huffingtonpost:

Scientists have put the incredible smelling powers of a dog to good medical use.

Sniffing out cancer.

Japanese scientists trained a black Labrador Retriever, named Marine, that they say can sniff out colorectal cancer with up to 98 percent accuracy, according to CTV News. Better yet perhaps, her abilities are more accurate than some tests currently used to diagnose the cancer, namely the fecal occult blood test, which accurately predicts the cancer only 10 percent of the time.

This isn't the first time dogs have been used to diagnose malignancies like this either. The idea has also been used to test for skin, bladder, lung, breast and ovarian cancers as well, according to ABC News.

So how were they able to hone Marine's predicting abilities?

Previous studies have shown that dogs have the ability to sniff out cancer in patients' breath, according to National Geographic. Using this idea, the female Lab was trained to sit in front of samples that contained signs of cancer.

From CTV:

Marine was taught to sniff cups of exhaled breath samples and then to sit down in front of the cup that contained the sample from the patient with cancer. When Marine got it right, she was rewarded with a tennis ball.

A dog's sense of smell is up to 1 million times better than a human being's. However, not all dogs have the same abilities.


From Bloomberg Businessweek:

A dog trained to sniff out colorectal cancer was almost as accurate as a colonoscopy in a study that suggests less invasive tests for the disease may be developed.

The Labrador retriever was at least 95 percent as accurate as colonoscopy when smelling breath samples, and 98 percent correct with stool samples, according to the study, published today in the medical journal Gut. The dog’s sense of smell was especially effective in early-stage cancer, and could discern polyps from malignancies, which colonoscopy can’t.

“Most striking is the ability of the dogs to detect bowel cancer at its earliest stages,” Trevor Lockett, a bowel cancer researcher with the Commonwealth Scientific and Industrial Research Organisation in Australia.

Most current non-invasive tests for bowel cancer identify later-stage disease far more efficiently than early-stage, Lockett said.

“Detection of early-stage cancers is the real holy grail in bowel cancer diagnosis because surgery can cure up to 90 percent of patients who present with early-stage disease,” he said.

Sniffing Samples

In the study, the dog sniffed samples from 48 people with confirmed bowel cancer and 258 volunteers who were either healthy or had survived cancer. The dog was asked by his handler to find the one malignant sample in a set of five.

“This study shows that a specific cancer smell does indeed exist,” the researchers said in the study. “These odor materials may become effective tools in screening.”

While dogs have previously been shown to identify skin, bladder, lung, breast and ovarian malignancies, canines are too expensive and too fickle to rely on for routine cancer diagnoses, the researchers said.

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