How accurate are cancer-sniffing dogs?

Dogs are used for many amazing purposes, from search-and-rescue missions to sniffing out bombs. A well-trained dog can do almost anything — including using its powerful sense of scent for medical reasons.

Dogs’ noses have hundreds of millions of scent receptors, while humans only have about 400. A dog’s nose is so sharp that it can pick up even the most subtle traces of scent. Now, the medical world is turning to dogs to detect and locate a main cause of death in the U.S. — cancer.

How does canine cancer detection work?

Dogs have an incredible sense of smell. They can differentiate between millions of scents – including the odors given off by different types of cancer cells and biomarkers in patients with cancer.

When properly trained to detect odor signatures from cancer cells, cancer-sniffing dogs can accurately distinguish a cancer sample from a noncancerous sample. These dogs can work off of many different types of samples.

• Blood
• Blood plasma
• Breath
• Skin
• Stool
• Sweat
• Urine

Medical detection dogs can alert physicians to the presence of cancer odors in a sample – even samples that contain very low concentrations. Canine cancer detection has been successfully used to detect melanoma, lung cancer, colorectal cancer, colon cancer, ovarian cancer, prostate cancer, and breast cancer.

Studies support the accuracy of cancer-sniffing dogs

Cancer-sniffing dogs first started when dogs that were not trained to seek out cancer kept pestering their owners – for example, a dog kept sniffing and even biting at one woman’s mole, only to find that it was malignant melanoma. From then on, trainers began intentionally teaching dogs to sniff out cancer. Over the years, several studies have supported the accuracy of canine cancer detection.

• Science Daily. A study published on April 8, 2019, found that cancer-sniffing dogs can use their noses to pick out which blood samples are from people with cancer with an accuracy of about 97%.
• BMC Cancer. An older study from 2013 found positive results when testing whether trained dogs can detect cancer cells in blood samples. This study found both a 97% and a 99% success rate for detecting cancer cells or biomarkers in blood and blood plasma.
• Front Vet Sci. On March 14, 2018, Front Vet Sci published a study on cancer-sniffing dogs. The study used breath samples to test a dog’s ability to detect lung cancer. The results found that both test subjects chose the correct samples, providing proof of concept.

The medical field has had enough success using cancer-sniffing dogs to view canine cancer detection as a viable alternative medicine form. The benefits that come with cancer-sniffing dogs include a low-risk noninvasive procedure, fast results, and less money spent on medical tests. Further research is required, however, to prove the reliability of canine cancer detection.

How are cancer-sniffing dogs trained?

Dog breeds genetically predisposed to have heightened senses of smell, such as bloodhounds, Labradors, and German Shepherds, undergo significant training to become cancer-sniffing canines.

They go through dozens of training sessions over several months to distinguish control samples from cancer-positive samples. They also undergo training sessions for odor discrimination. Positive reinforcement is the most common form of training for detection dogs.

At the end of their training, cancer-sniffing dogs have to pass a final test before working on actual samples. Currently, canine cancer detection is only used on samples, not on people. The dogs that pass the training and test can move onto being used to detect cancer in patient samples as an alternative form of medicine.

Next steps 

Modern science wishes to ultimately replace cancer-sniffing dogs with electronic sensors to eliminate errors and biases. Today, however, it may be possible to use a cancer-sniffing dog to detect cancer in you or a loved one by contacting a provider of this service, such as the In Situ Foundation or BioScentDX, Inc.

Alana Redmond is a content writer that specializes in law and consumer safety. She also works with Torgenson Law, a Phoenix personal injury law firm that specializes in dog bite injuries.

 

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