India Gazette Tuesday 10th March, 2015
• The thyroid is a gland in the neck that produces hormones to regulate metabolism.
• Thyroid tumours are normally diagnosed by testing hormone levels in the blood and by extracting cells for testing
• Frankie gave the correct diagnosis in 30 out of 34 cases
WASHINGTON A trained dog can identify from the smell of the urine samples whether a thyroid patient had malignant or benign (noncancerous) tumor with 88.2 percent accuracy, according to a new study presented by US researchers at the 97th annual meeting of the Endocrine Society in San Diego.
“Current diagnostic procedures for thyroid cancer often yield uncertain results, leading to recurrent medical procedures and a large number of thyroid surgeries performed unnecessarily,” said Donald Bodenner, head of endocrine oncology at the University of Arkansas for Medical Sciences (UAMS) in Little Rock, who is the study’s senior investigator.
The thyroid is a gland in the neck that produces hormones to regulate metabolism. Thyroid tumours 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 with their own unique chemistry, which 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.
“Scent-trained canines could be used by physicians to detect the presence of thyroid cancer at an early stage and to avoid surgery when unwarranted,” Bodenner commented presenting his paper on Friday.
Frankie, a 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.
“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],” Dr Bodenner said.
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.
Commenting on the findings Dr Jason Wexler, an endocrinologist in Washington, 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.”
Although Bodenner is not yet basing patient treatment decisions on the canine technique, he said the dog’s diagnostic accuracy is only slightly less than that of fine-needle aspiration biopsy, the method generally used first to test thyroid nodules for cancer.
Canine scent detection has the advantages of being noninvasive and inexpensive, he said.
Bodenner’s colleague and a study-coauthor, Arny Ferrando said, “Frankie is the first dog trained to differentiate benign thyroid disease from thyroid cancer by smelling a person’s urine.”
In this study, 34 patients gave a urine sample at their first visit to the university thyroid clinic before they went on to have a biopsy of suspicious thyroid nodules and surgery. The surgical pathology result revealed cancer in 15 patients and benign thyroid problem in 19.
These urine samples were presented, by a gloved dog handler, one at a time to Frankie to sniff. Neither the dog handler nor the study coordinator, who recorded the dog’s responses after the handler announced them, knew the cancer status of the 34 urine samples.
The handler interspersed some urine samples that had a known cancer status so he could reward the dog for correct answers: alerting to a cancer sample by lying down, and turning away from a benign sample to alert the absence of cancer.
The dog’s alert matched the final surgical pathology diagnosis in 30 of the 34 study samples, the investigators reported.
The sensitivity, or true-positive rate, was 86.7 percent, meaning Frankie correctly identified nearly 87 percent of the pathology-proven thyroid cancers.
The specificity–the true-negative rate–was 89.5 percent, which meant Frankie knew that a benign sample was actually benign almost 9 of every 10 times.
There were two false-negative results and two false-positives using canine scent detection.
Bodenner said they plan to expand their program by collaborating with Auburn University College of Veterinary Medicine in Auburn, Alabama. The veterinary school reportedly will dedicate two of its bomb-sniffing dogs to become trained thyroid cancer-sniffing dogs using UAMS patient samples.
Thyroid cancer affects over 60,000 people in the United States every year, according to the American Cancer Society. At least 1,900 of them die every year.
Early detection greatly helps as the survival rate is very high. Dr. Maria Pena, an endocrinologist at North Shore-LIJ’s Syosset Hospital in New York, agreed dogs may help complement the current thyroid nodule biopsy process
This research is still early, and experts note findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.