Dogs found to have a nose for sniffing out cancer

Dogs can accurately sniff out the early stages of bowel cancer, according to a new study.

Chemical compounds specific to some cancers are thought to be contained in breath and stool samples, which dogs can detect with a high degree of accuracy.

The finding could pave the way for a screening test to pick up signs of the disease before it has spread around the body.

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The current NHS screening programme uses a faecal blood test, which detects minute amounts of blood in stools – a sign of bowel cancer.

But researchers behind the latest study say this only picks up one in 10 cases of early stage bowel cancer.

For their research, published in the journal Gut, a Labrador Retriever completed 74 sniff tests.

These included samples of exhaled breath and stools obtained from 48 people with bowel cancer and from 258 healthy volunteers who have never had cancer or who had it in the past.

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Each test group consisted of one sample from a patient with bowel cancer, and four control samples from those without cancer.

These five samples were then randomly and separately placed into five boxes.

The Labrador, which had been specifically trained in scent detection for cancer, first smelled a breath sample from a patient known to have bowel cancer.

The dog then walked along the boxes, sitting down in front of the sample which it believed matched the cancer scent.

The test was then repeated with different boxes.

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The Labrador's ability to detect cancer in breath samples was 95 per cent accurate overall, and was 98 per cent accurate for stool samples.

"The accuracy of canine scent detection was high even for early cancer," said the researchers, from universities and hospitals in Japan. They said they thought dogs may be able to sniff out other cancers too.

While it may be difficult to use dogs in clinical practice because of the expense and the time it takes to train them, cancer-specific compounds detected by dogs could be incorporated into a new test, they said.

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