Sniffing out cancer

Claire visits the team at K9 Medical Detection Charitable Trust to learn how their dogs are being trained to detect bowel and prostate cancer.

Levi loves what he does. He gets picked up each morning at 8:30am, happy and excited to go to work. He spends his time investigating samples, figuring out whether they contain cancer or not. His payment - toys and play time.

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Levi is a German Shephard with a finely tuned olfactory system - a nose perfectly adapted to smelling, around 225 million scent receptors and a large part of the brain designated to distinguishing smells.

He is part of the K9 Medical Detection Charitable Trust team based at AgResearch in Invermay. Alongside his colleagues Wētā, Frieda, Magic and puppy Ace, Levi has been training to do one job extremely well - sniff out bowel cancer.

Trainer Courtney Moore works with the dogs - helping them to 'imprint' on the cancer scent from an early stage. It is unclear exactly what the dogs are sniffing out - it is likely to be metabolites or volatile organic compounds released by the cancer cells into the solutions they are in - but the dogs are able to distinguish a unique cancer 'scent'. The imprinting is part of the first 'proof of concept' phase, a validation step that the dogs must pass through where they show they can selectively pick which of the saline samples contain the cancer cells, and ignore those that contain healthy cells.

Levi has already passed this validation step with flying colours with regards detecting bowel cancer, and the team hope that Wētā will soon follow. Frieda has recently passed for prostate cancer detection with 100% selectively and specificity. The next phase is a test of diagnostic accuracy, says director Pauline Blomfield. This would involve the dogs investigating urine samples from patients.

The goal is to provide a non-invasive, value-added tool to existing cancer screening methods. In addition, identifying the volatile organic compounds the dogs are detecting could provide a further opportunity to develop specific and selective diagnostic tests based on these molecules, says Professor Sarah Young of the University of Sydney, one of the scientists who work with K9 Medical Detection.

While it is still relatively early days in terms of the dogs providing help with cancer diagnoses, the dogs have achieved good results so far and the team have faith in their strong work ethic and amazing noses. Levi is just happy to do something he loves each day.

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Go to this episode on rnz.co.nz for more details