Olfactory system of highly trained dogs detects prostate cancer in urine samples

Abstract

Purpose: We established diagnostic accuracy in terms of the sensitivity and specificity with which a rigorously trained canine olfactory system could recognize specific volatile organic compounds of prostate cancer in urine samples.

Materials and methods: Two 3-year-old female German Shepherd Explosion Detection Dogs were trained to identify prostate cancer specific volatile organic compounds in urine samples. They were tested on 362 patients with prostate cancer (range low risk to metastatic) and on 540 healthy controls with no nonneoplastic disease or nonprostatic tumor. This cross-sectional design for diagnostic accuracy was performed at a single Italian teaching hospital and at the Italian Ministry of Defense Military Veterinary Center.

Results: For dog 1 sensitivity was 100% (95% CI 99.0-100.0) and specificity was 98.7% (95% CI 97.3-99.5). For dog 2 sensitivity was 98.6% (95% CI 96.8-99.6) and specificity was 97.6% (95% CI 95.9-98.7). When considering only men older than 45 years in the control group, dog 1 achieved 100% sensitivity and 98% specificity (95% CI 96-99.2), and dog 2 achieved 98.6% sensitivity (95% CI 96.8-99.6) and 96.4% specificity (95% CI 93.9-98.1). Analysis of false-positive cases revealed no consistent pattern in participant demographics or tumor characteristics.

Conclusions: A trained canine olfactory system can detect prostate cancer specific volatile organic compounds in urine samples with high estimated sensitivity and specificity. Further studies are needed to investigate the potential predictive value of this procedure to identify prostate cancer.

Keywords: diagnosis; dogs; olfactory perception; prostatic neoplasms; volatile organic compounds.