Studies Prove Dogs Can Sniff Out Disease

Two separate studies prove that dogs can detect thyroid and prostate cancer using sense of smell.

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Could the future of diagnosing some cancers include dogs sniffing them out? Vladimir Semenov/iStock/Thinkstock

It seems that every day you read another story about a dog rescuing their owner from a burning building or being heroic in a dangerous situation, proving that Lassie rescuing Timmy from the well is more than just a work of fiction. In these cases the term “man’s best friend” really doesn’t do canines justice.

Truthfully, I can’t say that my childhood dog, Candy, ever did anything to save my life, but he did try to protect me when my dad yelled at me, and I always felt safe when he was around.

Recently, two new studies have come out that show dogs can do more than just rescue people from danger; they can help in identifying deadly diseases.

Detecting Thyroid Cancer With A Sniff
A research team from the University of Arkansas for Medical Sciences (UAMS) in Little Rock conducted a study to train a dog to differentiate cancerous from non-cancerous thyroid illness by sniffing human urine samples. The study was presented at the Endocrine Society’s 97th Annual Meeting in San Diego earlier this year.

In the experiment, Frankie, a male German Shepherd mix, was trained to tell the difference between benign thyroid disease and thyroid cancer just by sniffing the urine samples. He correctly identified the thyroid cancer status 30 out of 34 times — an astounding accuracy rate.

The way the test worked, Frankie would lie down when sniffing a cancer-positive urine sample, and he would turn away from a benign sample. The cancer status of each urine sample was unknown to both the dog handler and the study coordinator. The handler also used urine samples with a known cancer status so Frankie could be rewarded for a correct answer.

The true-positive rate of the canine scent detection came in at 86.7 percent, and the true-negativity rate was 89.5 percent. This basically means Frankie identified a benign sample roughly nine out of 10 times.

Thyroid cancer begins in the thyroid gland, below the thyroid cartilage in front of the neck. Thyroid cancer is very common in the United States, with approximately 62,000 new cases diagnosed every year and nearly 2,000 Americans dying from it annually. This cancer is more common in young adults, unlike many other forms of cancer, with almost two in three new diagnoses being for people under 55.

A common way to diagnose thyroid cancer is by having a needle inserted into the thyroid gland for a tissue sample, and the test is about 95 percent accurate.

In a press release from the Endocrine Society, Dr. Donald Bodenner, chief of endocrine oncology at UAMS, says that the diagnostic accuracy of the canine scent detection is almost equal to the fine-needle aspiration biopsy, but would be a significantly less expensive alternative.

Bodenner believes that many other methods used to diagnose thyroid cancer have less accuracy, making patients undergo unnecessary surgery.

“Scent-trained canines could be used by physicians for diagnosing thyroid cancer at an early stage and to avoid surgery when unwarranted,” Bodenner told the Endocrine Society.

The researchers obtained the urine samples for the experiment from 34 patients who attended the thyroid clinic stationed at UAMS. All patients had abnormalities in their thyroid nodules, going on to have biopsies and surgery. Thyroid cancer was identified in 15 patients, and 19 patients had benign thyroid disease.

The researchers plan to grow their research by having two bomb sniffing dogs, courtesy of Auburn University College of Veterinary Medicine, train for thyroid cancer detection.

Dogs Can Also Sniff Out Prostate Cancer
A second recent study, conducted by the Department of Urology at the Humanitas Clinical and Research Centre in Milan, revealed that dogs have a 98 percent reliability rate in sniffing out prostate cancer in men.

The Italian study involved two German Shepherd dogs sniffing the urine of 900 men, 360 with prostate cancer and 540 without.

The results backed up previous research carried out by Medical Detection Dogs that found a 93 percent reliability rate.

“These results are spectacular. They offer us further proof that dogs have the ability to detect human cancer,” Claire Guest, co-founder of Medical Detection Dogs, told the Daily Telegraph. “It is particularly exciting that we have such a high success rate in the detection of prostate cancer, for which the existing tests are woefully inadequate.”

Prostate cancer is the most common cancer in men in the United Kingdom, with more than 40,000 new cases diagnosed every year. In the United States, the numbers are even worse. More than 220,000 new cases are discovered each year and approximately 28,000 men die from it annually.

The power of a dog’s nose can be something that can do wonders to save lives. Hopefully, this is just the beginning of what lies ahead.

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