Study senior investigator Donald Bodenner, MD, PhD said “Current diagnostic procedures for thyroid cancer often yield uncertain results, leading to recurrent medical procedures and a large number of thyroid surgeries performed unnecessarily.” Bodenner is chief of oncology at the University of Arkansas for Medical Sciences (UAMS) in Little Rock.
The study will be presented at the Endocrine Society’s 97th annual meeting in San Diego.
Bodenner does not base patient treatment decisions on the results provided by dogs, but he said the dog’s diagnostic accuracy is slightly less effective compared to fine-needle aspiration biopsy – the general method used to test thyroid nodules for cancer. With a canine scent detection technique, patients have the added advantage of a noninvasive and inexpensive procedure, he said.
“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.
In the study, 34 patients offered a urine sample at their first visit to the university thyroid clinic before having a biopsy of suspicious thyroid nodules and surgery. The results were categorized as cancer in 15 patients and benign in 19. The urine samples were presented, one at a time, to Frankie the dog to sniff. Neither the dog handler nor the study coordinator knew the cancer status of the 34 urine samples.
The handler mixed some urine sample had a known cancer status to reward to dog or correct answers. The dog would indicate a cancer sample by lying down, or turning away from a benign sample or complete 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.