Further, the sensitivity and specificity of this method were both greater than 85%, according to the data.
“The gold standard in determining whether or not a nodule is cancerous is a fine needle aspiration biopsy. In other words, you stick a needle into that nodule and get some cells, which in most cases has about a 95% accuracy,” study researcher Donald Bodenner, MD, PhD, chief of endocrine oncology at the University of Arkansas for Medical Sciences (UAMS) in Little Rock, said during a press conference.
“We’re not there yet, but I think we’re very close in terms of finding a noninvasive and inexpensive adjunct to current diagnostic practice.”
In a previous study, Dr. Bodenner and colleagues found that canines could reliably discriminate between urine samples obtained from subjects previously diagnosed with metastatic thyroid carcinoma or benign thyroid disease. In this study, they aimed to test a canine’s ability to prospectively detect thyroid cancer in undiagnosed patients.
The researchers collected urine samples from patients who presented to the thyroid unit at their institution. If a patient had at least one thyroid nodule — in some cases, patients had three, four or five nodules —urine samples were immediately collected. Inclusion criteria dictated that patients had to go on to surgery or have some kind of pathology to which the researchers could compare their findings and that the patients have conventional papillary thyroid cancer and no other cancers present.
A total of 15 patients with papillary thyroid cancer and 19 patients with benign nodules were included in the study. The trained scent dog, a rescued German Shepherd mix named Frankie, involved in this particular study was trained to lie down whenever he detected papillary thyroid cancer in the sample or just turn away or do nothing.
Results revealed that 30 of 34 samples were detected correctly (accuracy, 88.2%) while the sensitivity, or the ability to determine whether a sample was negative, was 86%. Specificity, or the ability to identify positive samples correctly, was 89%.
In light of these positive results, Dr. Bodenner said that the researchers are considering new areas for future study.
“What we’d like to look at in the future is monitoring high-risk thyroid cancer patients whom we think are cured but have a high probability of having a recurrence,” he said.
“Another thing that we’re very interested in is trying to find out what these dogs are actually smelling. Right now, no one really has any idea what the scent profile is that’s triggering their response, and so we want to use proteomics or metabolomics or some of these other methodologies to try to pinpoint exactly what they are.”
If the results are confirmed in larger studies, they could have important clinical implications, according to Dr. Bodenner.
“One thing that would be very interesting is to try to employ this methodology in underserved communities or third world countries because you don’t need a big clinic or an ultrasound; you just need a urine sample that is transported correctly,” Dr. Bodenner said.
He also noted that he and his researchers would like to collaborate with Auburn University’s veterinary department, as it is the predominant institution that supplies animals to the United States Department of Defense for bomb detection.
“With all of these animals coming home from Afghanistan and Iraq, they don’t know what to do with them, so we’re looking to repurpose some of those to look at various cancers,” Dr. Bodenner said.
Additionally, he and his team are looking into the possibility of canines’ ability to detect other types of cancers, including ovarian cancer.
- Hinson AM et al. Abstract FRI-036. Presented at: The Endocrine Society’s 97th Annual Meeting & Expo; March 5-8, 2015; San Diego.