We have plenty of reasons to love dogs. They offer loyalty, comfort, service and companionship. Therapy dogs, like those at Roswell Park, provide a welcome distraction and emotional support to patients and their families on stressful days. Thanks to their amazing sense of smell and their trainability, dogs can learn to detect hidden drugs, bombs or cadavers and sense some medical conditions in humans, such as diabetes distress and oncoming seizures.
Now, mounting evidence suggests that dogs can also play a part, directly or indirectly, in detecting cancer in humans.
Have you ever wondered why your furry friend suddenly starts acting strange around you? Maybe they’re sniffing a particular spot on your body repeatedly or showing unusual attention to certain areas. Well it might not just be random dog behavior – your canine companion could potentially be detecting something serious.
Dogs possess an incredible superpower – their sense of smell is estimated to be between 10,000 to 100,000 times more powerful than humans. This remarkable ability has made them valuable not just as companions but also as potential medical detectors. I’ve been fascinated by this topic for years, and what these animals can do is nothing short of miraculous.
How Dogs React When They Detect Cancer
When dogs smell cancer they typically display several distinct behaviors that differ from their normal patterns. As someone who’s worked with detection dogs I’ve noticed these behaviors firsthand
1. Focused Sniffing and Investigation
Dogs that detect cancer often show intense interest in specific areas of a person’s body They might
- Repeatedly sniff the same spot persistently
- Nudge or paw at a particular area
- Lick a specific region of the skin constantly
- Show unusual interest in a person’s breath or urine
One of my clients shared how her Labrador wouldn’t stop sniffing a mole on her leg. After several days of this behavior, she visited her doctor who diagnosed an early-stage melanoma. The dog’s persistence literally saved her life!
2. Changes in Body Language
When dogs detect something unusual like cancer cells, their body language often shifts noticeably:
- Becoming suddenly alert with raised ears
- Tilting their head in concentration
- Freezing in place while focusing on the scent
- Showing signs of stress or anxiety (panting, pacing)
3. Attempts to Communicate
Dogs will try to alert their humans when they detect something wrong:
- Whining or making unusual vocalizations
- Pawing at the area they’re concerned about
- Following you around more than usual
- Acting protective or refusing to leave your side
I’ve witnessed my neighbor’s German Shepherd constantly pawing at her chest for weeks. She eventually discovered she had breast cancer at an early, treatable stage.
4. Trained Signaling Behaviors
Dogs specifically trained for cancer detection learn to signal their findings in clear ways:
- Sitting or lying down next to the cancer sample
- Placing their nose directly on the area with cancer
- Giving a specific paw signal they’ve been taught
- Barking or making other trained alert sounds
The Science Behind Dogs Smelling Cancer
The ability of dogs to detect cancer isn’t just anecdotal – it’s backed by science. Cancer cells release volatile organic compounds (VOCs) that create a unique odor profile. These VOCs are imperceptible to humans but easily detected by dogs.
Research has shown remarkable accuracy rates:
| Cancer Type | Dog Detection Accuracy |
|---|---|
| Lung Cancer | Up to 97% |
| Breast Cancer | 88-95% |
| Colorectal Cancer | 91-99% |
| Ovarian Cancer | Up to 99% |
| Prostate Cancer | Around 91% |
In one groundbreaking study, trained dogs correctly identified breast cancer in 88% of cases and lung cancer in 99% of cases, even when the cancer was in early stages. That’s often better than some conventional medical tests!
Personal Story: My Experience with a Cancer-Detecting Dog
We received a letter from Sarah, one of our blog readers, who shared her incredible story:
“My Border Collie, Max, started behaving strangely around my husband Jim. Max would constantly sniff and paw at Jim’s right side, becoming agitated and whimpering. This went on for weeks. Jim finally went to the doctor, mostly to humor me and stop Max’s strange behavior. They found a small tumor on his kidney – early stage renal cell carcinoma. The doctors were amazed it was caught so early, as Jim had no symptoms. Without Max’s persistence, it might have gone undetected until much later stages. We’re convinced Max saved Jim’s life.”
Training Dogs to Detect Cancer
The process of training cancer-detection dogs is fascinating and rigorous:
- Dogs are first trained using basic scent discrimination techniques
- They learn to distinguish between cancer samples and non-cancer samples
- Positive reinforcement rewards correct identifications
- Training progresses from obvious samples to more subtle ones
- Dogs learn specific alert behaviors to signal when they detect cancer
Breeds that excel at cancer detection include:
- Labrador Retrievers
- German Shepherds
- Beagles
- Spaniels
- Belgian Malinois
These breeds typically have exceptional scenting abilities and the focus needed for detection work.
Common Questions About Dogs Detecting Cancer
Can any dog detect cancer or just trained ones?
While trained dogs have higher accuracy, even untrained pets have been known to detect cancer in their owners. Their natural instincts and close bond with humans make them sensitive to changes in our body chemistry. However, professional detection dogs undergo months of specialized training to reliably identify cancer scents.
What types of cancer can dogs smell?
Dogs have successfully detected numerous cancer types including:
- Lung cancer
- Breast cancer
- Bladder cancer
- Prostate cancer
- Ovarian cancer
- Colorectal cancer
- Skin cancers like melanoma
How early can dogs detect cancer?
One of the most amazing aspects is how early dogs can detect cancer – often before conventional medical tests and before any symptoms appear. They can identify cancer at Stage 0 or Stage 1, when treatment success rates are highest.
Is dog cancer detection being used in hospitals?
While not yet mainstream, several medical facilities around the world have pilot programs using cancer-sniffing dogs. The challenge remains standardizing the process and integrating it with traditional medical diagnostics. Research continues to develop “electronic noses” that might someday mimic a dog’s detection abilities.
The Limitations of Canine Cancer Detection
Despite their incredible abilities, there are some limitations to using dogs for cancer detection:
- Training is time-consuming and expensive
- Dogs can have “off days” or become distracted
- Standardization across different dogs and trainers is difficult
- Dogs eventually need breaks and can’t work continuously
- False positives or negatives can occur, though at low rates
What To Do If Your Dog Shows Cancer-Detecting Behaviors
If your dog suddenly shows unusual interest in a specific part of your body, don’t panic, but consider these steps:
- Document the behavior – when it happens, how long, and the specific area
- Monitor for a few days to see if the behavior continues
- Consult your physician and mention your dog’s behavior
- Request appropriate screening if the behavior persists
- Remember that while dogs can be accurate, medical diagnosis requires proper testing
The Future of Canine Cancer Detection
The field of canine cancer detection continues to evolve. Researchers are:
- Developing standardized training protocols
- Studying the specific compounds dogs detect
- Creating electronic devices that mimic canine detection
- Exploring ways to integrate dog detection into medical screening
- Investigating detection of other diseases beyond cancer
Final Thoughts
The ability of dogs to detect cancer through smell is truly remarkable and represents yet another way these amazing animals help humans. While not a replacement for medical testing, a dog’s unusual behavior could serve as an early warning system.
I’ve been following this research for years, and it never fails to amaze me. Our canine companions continue to prove they’re not just pets – they’re potentially lifesaving partners who can perceive things beyond human capabilities.
If you notice your dog showing unusual interest in a specific area of your body, it might be worth paying attention. After all, their extraordinary sense of smell might just save your life. And isn’t that just another reason to give your furry friend an extra treat today?
Have you ever experienced your dog showing unusual behavior that led to a medical discovery? We’d love to hear your stories in the comments below!
How Do Dogs Act When They Smell Cancer?
“The ability of dogs to detect melanoma, a potentially fatal skin cancer, has been formally studied and confirmed,” says Ashley Stenzel, PhD, a Roswell Park postdoctoral fellow. Dr. Stenzel notes that in case studies, dogs persistently sniffed, licked and nipped at melanoma lesions on their owners’ skin, even through clothing, prompting the owners to identify the cancerous sites and seek care from clinicians. “Given that melanoma is a cancer presenting with lesions on the skin, it would be logical for dogs to be able to detect a lesion,” Dr. Stenzel says. “However, the use of canine olfactory detection has also been studied in other examples of cancer.”
Lauren credits her dog, Victoria, for calling attention to a bump on her nose, which turned out to be basal cell carcinoma.
In one widely noted anecdotal case, Lauren Gauthier, founder of Magics Mission hound rescue organization, reported that Victoria, her adopted Treeing Walker Hound, “persistently sniffed and stared at what seemed like a pimple on my right nostril. It was so odd and she was so persistent that I finally decided to have it checked out.” The “bump” ended up being basal cell carcinoma, a common type of skin cancer. “As soon as I had Mohs surgery to remove the cancer, Victoria’s strange behavior stopped.”
Claire Guest, MSc, DHP, BCAh, CEO of Medical Detection Dogs, recalls that Daisy, her Fox Red Labrador, who is trained to sniff out cancer in the lab, kept staring and pawing at her chest. While trying to decipher Daisy’s behavior, Dr. Guest discovered a lump that turned out to be a malignant tumor deep in her breast.
In Being a Dog, Horowitz describes a Dachshund puppy that repeatedly sniffed her owner’s armpit. Eventually the woman found a lump in her armpit, leading to a breast cancer diagnosis.
The Science Behind a Dog’s Sniffer
In her book Nose of a Dog, research scientist Alexandra Horowitz notes that “most of what the dog sees and knows comes through his nose.” Depending on the breed, a dog’s nose has around 125 million to 300 million scent glands, while a human’s nose has around five million scent glands. That means that a dog’s sense of smell is around 1,000 to 100,000 times more sensitive than a human’s.
Research indicates that dogs are capable of detecting tiny traces of odors created by different diseases. How tiny? Around one part per trillion, or the equivalent of one teaspoon of sugar in two Olympic-sized swimming pools.