Tests on 34 patients showed an 88% success rate in finding tumours.
The team, presenting their findings at the annual meeting of the Endocrine Society, said the animal had an "unbelievable" sense of smell.
Cancer Research UK said using dogs would be impractical, but discovering the chemicals the dogs can smell could lead to new tests.
The thyroid is a gland in the neck that produces hormones to regulate metabolism.
Thyroid tumors are relatively rare and are normally diagnosed by testing hormone levels in the blood and by using a needle to extract cells for testing.
Cancers are defective, out-of-control cells. They have their own unique chemistry and release "volatile organic compounds" into the body.
The canine approach relies on dogs having 10 times the number of smell receptors as people and being able to pick out the unique smells being released by cancers.
The man's best friend approach has already produced promising results in patients with bowel and lung cancers.
A team at the University of Arkansas for Medical Sciences (UAMS) had previously showed that a dog could be trained to smell the difference between urine samples of patients with and without thyroid cancer.
The next step was to see if it could be used as a diagnostic test.
Frankie the German Shepherd was trained to lie down when he could smell thyroid cancer in a sample and turn away if the urine was clean.
Thirty-four patients, who were going to hospital for conventional testing, took part in the trial.
Frankie gave the correct diagnosis in 30 out of 34 cases. There were two false positives and two patients who would have been incorrectly given the all-clear.
Dr Donald Bodenner, the chief of endocrine oncology at UAMS, said: "The capability of dogs to smell minute amounts is unbelievable.
"The medical community over the next few years is going to have a great appreciation [for them].
Some researchers are trying to strip out the canine-element and test for the unique pong of cancer with an "electronic nose".
This approach is also being trailed outside of cancer and has been used to find dangerous infections such as Clostridium difficile.
Dr Bodenner added: "We would like to know what Frankie is smelling, nobody knows."
Commenting on the findings Dr Jason Wexler, an endocrinologist in Washington, DC, argued: "This is a fascinating, interesting study and it has high potential in areas of the world that may not have access to biopsy techniques.
"There are many patients who are reluctant to undergo fine needle aspiration so I think that if you could design a technique where you have no invasive procedure that can have tremendous widespread appeal."
But Dr Emma Smith, from Cancer Research UK, cautioned: "Although there's some evidence that some trained dogs can sniff out the smelly molecules given off by cancers, there have been mixed results on how accurate they are and it's not really practical to think about using dogs on a wide scale to detect the disease.
"But carrying out lab tests to understand what the dogs are smelling might help to inform the development of 'electronic noses' to detect the same molecules, which could lead to better diagnostic tests in the future."
Dr Bodenner says it is an approach that he is actively pursuing.
Meanwhile, the lab is also trying to find a new home for canine-veterans from Iraq and Afghanistan.
Instead of sniffing out bombs, they will be trained to hunt for cancer.
Source: BBC News
by Dr. Joanne Intile, DVM
Many owners administer herbal supplements to their pets with cancer with the hope that these alternative therapies will afford their pet a therapeutic edge in fighting the disease.
The amount of information suggesting the beneficial effects of various herbs, anti-oxidants, “immune boosting treatments,” and dietary supplements is astounding. The appeal of using a substance that is “natural” and “non-toxic” to disease is inarguably real.
What most owners fail to recognize is that herbal medications are not subject to the same regulations by the Food and Drug Administration (FDA) that prescription drugs are. Owners are also unaware that carefully worded claims to efficacy are not backed up by scientific research in the vast majority of cases, despite the plethora of supportive material listed on product inserts or on websites.
Legally, herbal supplements are considered “foods” and not “drugs.” Therefore, the FDA has minimal regulatory role over their production and advertising.
The FDA acts to ensure that there are no overtly misleading claims made by the manufacturer, and also mandates that it is illegal for a product sold as a dietary supplement to be promoted on its label, or in any of its labeling material, as a “treatment, prevention, or cure for a specific disease or condition.”
Dietary supplements do not need approval from the FDA before they are marketed. Except in the case of a new dietary ingredient, where pre-market review for safety data and other information is required by law, a firm does not have to provide the FDA with the evidence it relies on to substantiate safety or effectiveness before or after it markets its products.
A recent investigation was conducted by the New York State Attorney General’s office examining the integrity of various herbal supplements via DNA analysis of their ingredients. Results astonishingly showed that 4 out of 5 herbal products were found to contain none of the herbs listed on the ingredient label.
From the press release from the New York State Attorney General’s office:
Overall, just 21% of the test results from store brand herbal supplements verified DNA from the plants listed on the products’ labels — with 79% coming up empty for DNA related to the labeled content or verifying contamination with other plant material.
… 35% of the product tests identified DNA barcodes from plant species not listed on the labels, representing contaminants and fillers. A large number of the tests did not reveal any DNA from a botanical substance of any kind. Some of the contaminants identified include rice, beans, pine, citrus, asparagus, primrose, wheat, houseplant, wild carrot, and others. In many cases, unlisted contaminants were the only plant material found in the product samples.
Though the results of the investigation are concerning, one could argue a lack of accuracy in product integrity would do little harm other than waste the buyer’s money. As a veterinarian, what I worry about is whether what’s actually present in the supplement could be detrimental to my patient’s health.
Could these non-listed ingredients cause a severe allergic reaction in an animal? Could these additional ingredients interact negatively with a previously prescribed conventional treatment? Are they really safe?
I’m not arguing against using natural substances to treat disease. In fact, one of the most common chemotherapy drugs I prescribe is vincristine, a drug derived from the periwinkle plant. Aspirin was originally produced from salicylate containing plants such as the willow tree. And on a personal account, ginger is a definite anti-nausea remedy for my own occasionally sour stomach.
But I also know that many natural substances can be extremely toxic for pets. There are many species of poisonous wild mushrooms; botulin toxin (aka “Botox”) is natural, but can be deadly for animals; and yes, even the vincristine I prescribe routinely to my patients can be deadly if proper dosing is not maintained.
I’m concerned that owners are wasting their money on supplements touted as cure-alls for their pets. I worry that these substances could actually be causing harm to my patients because of unknown ingredients that interact negatively with prescribed medications or with that animal’s particular physiological constitution. And I have concerns that the average consumer isn’t aware of the lack of regulation of these substances, which is the impetus for writing this article.
Be sure to speak directly with your veterinarian in reference to your questions about supplements and their potential role in your pet’s healthcare. And be sure to let your pet’s doctor know about any supplements, vitamins, and other over the counter remedies you may be administering to your pet. An open dialogue is essential for making the best decisions about your furry companion’s well being.
To learn more, visit the American Cancer Society’s information page on supplements: Dietary Supplements: What is Safe?
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