Chapter 1: The Science Behind Canine Smell

Dogs possess a staggering 300 million olfactory receptors, which raises the intriguing question: can they sniff out cancer?

Photo by Alvan Nee on Unsplash

Canine companionship comes with numerous scientifically proven advantages. For instance, my dog Quincy helps alleviate feelings of loneliness, a phenomenon supported by a small-scale study from Australia suggesting that having a dog can diminish isolation.

Interestingly, owning a dog might even extend your lifespan. A thorough review has shown that dog owners often experience a reduced mortality risk, potentially due to better stress management and improved blood pressure.

Do dogs really help in reducing stress? Absolutely! Various studies confirm that dogs can effectively lower anxiety levels. These are just a few of the many perks associated with dog ownership and therapy. Today, however, I want to explore a fascinating development in the field of cancer research: the ability of dogs to detect cancer.

As you may know, dogs are renowned for their exceptional sense of smell. Their olfactory prowess has been harnessed in various scenarios, such as identifying explosives and narcotics at airports. Today, we will delve into the scientific evidence supporting dogs' capabilities in identifying various forms of cancer.

Humans have capitalized on dogs' extraordinary olfactory talents, training them to sniff out not just drugs and explosives, but also to detect viruses, bacteria, and even the presence of cancer in bodily fluids or tissues. Canine noses are adept at sensing volatile organic compounds, which can indicate health issues.

Potential samples for dogs to sniff include breath, urine, feces, skin, and sweat. In fact, dogs have been known to identify skin cancer, specifically malignant melanoma. In one notable case, a 43-year-old woman noticed her rescue dog frequently sniffing a mole on her back. This mole, which had been present since her youth, had recently started to grow.

Due to her dog's unusual behavior, the woman sought medical advice. Upon examination, the doctor found an ulcerated nodule at the edge of the brown patch.

A biopsy of the 1.5-centimeter lesion confirmed melanoma. Following surgery, the previously untrained dog would gently sniff her back and rest his head on her lap. Remarkably, at the seven-year follow-up, she remained cancer-free.

Dogs can detect odorant molecules at concentrations as low as one part per trillion, making their sense of smell more powerful than some of the most advanced technological devices, including gas chromatography-mass spectrometry.

You might wonder if dogs can also sense lung cancer. Given that we exhale air from our lungs, which likely contains detectable odorants, the answer is yes. In a research study, a 3-year-old Labrador Retriever and Pitbull mix was trained to identify lung cancer in exhaled gas samples.

The researchers conducted 785 trials using 390 samples collected from 113 individuals, including 28 control subjects. The results were impressive: the trained dog accurately identified lung cancer in 95% of the samples and correctly identified non-cancerous samples 98% of the time.

Another study assessed the ability of trained dogs to distinguish breast cancer cell cultures from normal cells, as well as to identify melanoma and lung cancer cells. In this study, two Belgian Shepherds were trained to detect these specific cancer cells and achieved a perfect accuracy rate in identifying both cancerous and non-cancerous specimens.

This small-scale study reinforces the hypothesis that cancer cells emit a distinct odor, which can be recognized across various types of cancer. Furthermore, dogs have been trained to detect prostate and ovarian cancer through urine samples.

With their incredibly sensitive olfactory systems, dogs offer a non-invasive method for detecting human cancers, including breast cancer, colorectal cancer, and melanoma. I am eager to see advancements in technology, such as the development of electronic noses that can reliably identify cancer signatures, as research in this area continues.

Chapter 2: Videos on Canine Cancer Detection

This video titled "Dogs That Smell Cancer" explores how dogs are trained to detect cancer through their extraordinary sense of smell, showcasing real-life cases.

The second video, "Dogs Can Smell Cancer | Secret Life of Dogs | BBC Earth," delves into the scientific studies that highlight the remarkable abilities of dogs in identifying cancerous cells.