Can Dogs Smell Cancer?

It’s long been a “given” that canines have a superior sense of smell–which is why we depend upon them for safety monitoring and search and rescue. Highly trained dogs can detect danger and have been historically relied upon to identify prey. But, can dogs also use their noses to identify cancer?

The answer is: yes.

Multiple scientific studies have determined that dogs can be trained to detect cancer after examining breath and urine samples from cancer patients. Individual studies have assessed dogs’ ability to specifically identify non-small cell lung cancer, prostate cancer, breast cancer, ovarian cancer, colorectal cancer, melanoma, and more. In some instances, trained dogs have identified cancer correctly 100% of the time.

How do dogs smell cancer, exactly? Cancer cells emit volatile organic compounds (VOCs); dogs can then be trained to identify VOCs by assessing urine or skin samples of cancer patients, for example. 

This is amazing, right? There’s a dream scenario: dogs are ubiquitous and even if someone’s missed their annual screening, they can’t avoid being around dogs who might determine their cancer–or so we might hope. 

Unfortunately, like any dog relied upon for screening duties, medical detection dogs must be highly trained, and there are still many unknowns surrounding dogs’ ability to contribute to cancer screening at scale. For example: are specific breeds better suited to this work than others?

But, the individual examples of amazing pets who have seemingly identified their owners’ cancer are awe-inspiring. Consider:

• Sierra, a Husky from Wisconsin, sniffed her owner’s stomach and grew incredibly upset–causing her owner Stephanie to seek a second opinion for abdominal symptoms she had been experiencing. Ultimately, Stephanie was diagnosed with Stage III ovarian cancer–and Sierra correctly “sniffed” two separate recurrences.
• Daisy, a Fox-red Labrador, kept pawing at her owner’s chest, who ultimately learned she had a tumor in her breast.
• Sox, a Jack Russell Terrier, consistently licked his owner’s head–for years before his owner was diagnosed with a brain tumor, on the same side of his head that Sox always licked and pawed at.

While we can’t rely on our favorite furry friends to diagnose cancer at scale, dogs (and pets of all kinds) can be a wonderful support during cancer treatment and survivorship; you can learn more about how to engage with a support animal during your cancer experience from the American Cancer Society.

Download the Outcomes4Me app for tips and resources about how to navigate your cancer care with confidence.