Can dogs really detect cancer in human beings.The idea that dogs may be able to detect cancer in humans first gained serious attention in the early 2000s, when a study conducted at the Pine Street Foundation in California, found that trained dogs were able to detect lung and breast cancer in human breath samples with an impressive degree of accuracy. Since then, numerous studies have been conducted to further explore this phenomenon:
A study published in 2006 in the journal Integrative Cancer Therapies found that trained dogs were able to detect lung and breast cancer with high accuracy by sniffing breath and blood samples.
In 2011, a study published in the British Medical Journal reported that a dog was able to correctly identify lung cancer in 71 out of 100 samples and non-cancerous samples in 372 out of 400.
In 2012, a team of researchers led by R. Ehmann at Ambulante Pneumologie (Stuttgart, Germany) published an article in the European Respiratory Journal reporting on a study in which trained dogs detected lung cancer with sensitivity of 90% and specificity of 72%. Their well-designed study involved 60 lung cancer patients and 110 healthy controls, and is novel for also including ‘‘disease controls’’ who were 50 patients with non-malignant lung disease. The findings of Ehmann et al. corroborate the results of an earlier study of canine scent detection of lung cancer, which reported sensitivity and specificity of 99%. Together, these two papers, which achieved high accuracy while using different dogs, trainers and human subjects, beg the question of where this might all be leading.
In another study published in the peer-reviewed open access journal PLOS One in 2015, researchers from the University of Arkansas for Medical Sciences found that trained scent dogs were able to detect the presence of ovarian cancer in blood samples with a sensitivity of 100% and a specificity of 95%. This study further added to the growing body of evidence supporting the notion that dogs have the ability to detect cancer in humans.
In a study published in the journal European Urology in 2019, Taverna et al. found that two specially trained German Shepherds were able to detect prostate cancer in urine samples with a sensitivity and specificity of 97% and 98%, respectively. Dr. Gian Luigi Taverna, who is a urologist at the Humanitas Research Hospital in Milan, Italy, is one of the leading researchers in this field. These results are particularly significant, as prostate cancer is the most common cancer in men and the second leading cause of cancer-related deaths in men worldwide.
So, how exactly do dogs detect cancer? It is believed that they are able to do so through their incredibly sensitive sense of smell. Unlike humans, who have approximately 5 million olfactory receptors, dogs have around 300 million, making their sense of smell up to 100,000 times more sensitive than ours. This allows them to detect even the faintest odors, including those associated with various types of cancer.
The actual mechanism by which dogs are able to detect cancer is not yet fully understood, but it is thought to involve the detection of volatile organic compounds (VOCs) that are released by cancer cells. These VOCs can be present in a person's breath, urine, or even their skin, and it is believed that dogs can be trained to recognize the unique odor profiles associated with different types of cancer.
In addition to the empirical evidence supporting the idea that dogs can detect cancer in humans, there have also been numerous anecdotal reports of dogs alerting their owners to the presence of cancer. These stories, while not scientific proof in and of themselves, add to the growing body of evidence supporting the idea that dogs may indeed have a role to play in cancer detection.
While the evidence supporting the idea that dogs can detect cancer in humans is certainly compelling, there are still many unanswered questions in this field. For example, it is not yet clear exactly how reliable and accurate dogs' cancer-detecting abilities are, and further research is needed to better understand the mechanisms by which they are able to do so. Nevertheless, the data and literature support the notion that dogs may have a valuable role to play in cancer detection, and further research in this area is certainly warranted.
In conclusion, the evidence supporting the idea that dogs can detect cancer in humans is growing, with numerous studies and anecdotal reports suggesting that dogs may have the ability to detect cancer through their incredibly sensitive sense of smell. While there are still many unanswered questions in this field, the data and literature are certainly compelling, and further research will undoubtedly shed light on the potential of using dogs as a tool for cancer detection.