Contribution of canine olfaction in the diagnostic strategy of intermediate and high-risk prostate cancer: a double-blind validation study

Prostate cancer diagnosis is confirmed with a prostate biopsy, which is invasive and unpleasant. Adding canine olfaction into the diagnostic protocol could help avoid unnecessary biopsies. This study aims to determine whether dogs can identify ISUP (International Society of Urological Pathology) > 2 prostate cancer.

This double-blind, prospective, validation study included men with suspected prostate cancer between November 2022 and April 2023 in France. They were classified into two groups according to their prostate biopsy results; cases (ISUP > 2) and controls (ISUP < 1 or negative). Seven dogs analyzed their urine. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for canine olfactory detection of ISUP ≥ 2 prostate cancer were measured and compared with that of prostate MRI versus prostate biopsy.

The seven dogs analyzed 151 urine samples, 78 from the case group and 73 from the control group. The minimal and maximal observed values were 54% and 86% for sensitivity, and 69% and 88% for specificity. Five dogs had a sensitivity above 73% and six dogs had a specificity above 75%. The kappa coefficient quantifying agreement between the biopsy result and the MRI PI-RADS ≥ 3 was 0.17 [− 0.14; 0.17], 0.20 [0.02–0.33] for PI-RADS ≥ 4 and 0.64 [0.5–0.75] for canine olfaction meaning there is a substantial agreement between the biopsy result and canine olfaction.

Based on this study, the non-invasive and safe canine olfaction technique seems reliable for diagnosing ISUP ≥ 2 prostate cancer. Combined with prostate MRI, it may improve the decision-making process when choosing to perform prostate biopsies.