Olfactory detection of prostate cancer by dogs sniffing urine: a step forward in early diagnosis.
BACKGROUND
Volatiles organic compounds (VOCs) in urine have been proposed as cancer biomarkers.


OBJECTIVE
To evaluate the efficacy of prostate cancer (PCa) detection by trained dogs on human urine samples.


METHODS
A Belgian Malinois shepherd was trained by the clicker training method (operant conditioning) to scent and recognize urine of people having PCa. All urine samples were frozen for preservation and heated to the same temperature for all tests. After a learning phase and a training period of 24 mo, the dog's ability to discriminate PCa and control urine was tested in a double-blind procedure. Urine was obtained from 66 patients referred to a urologist for elevated prostate-specific antigen or abnormal digital rectal examination. All patients underwent prostate biopsy and two groups were considered: 33 patients with cancer and 33 controls presenting negative biopsies.


METHODS
During each "run," the dog was asked to signal a cancer urine among six samples containing only one cancer urine and five randomly selected controls. Sensitivity and specificity of the test were assessed.


CONCLUSIONS
The dog completed all the runs and correctly designated the cancer samples in 30 of 33 cases. Of the three cases wrongly classified as cancer, one patient was rebiopsied and a PCa was diagnosed. The sensitivity and specificity were both 91%.


CONCLUSIONS
This study shows that dogs can be trained to detect PCa by smelling urine with a significant success rate. It suggests that PCa gives an odor signature to urine. Identification of the VOCs involved could lead to a potentially useful screening tool for PCa.
Department of Urology, Tenon Hospital, Assistance Publique-Hôpitaux de Paris, University Paris VI, Paris, France. jncornu@hotmail.fr
Jean-Nicolas
JN
Cornu
Géraldine
G
Cancel-Tassin
Valérie
V
Ondet
Caroline
C
Girardet
Olivier
O
Cussenot
D000818:Animals; D014408:Biomarkers, Tumor / Q000652:urine; D003213:Conditioning, Psychological; D004285:Dogs; D042241:Early Diagnosis; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000652:urine*; D012680:Sensitivity and Specificity; D012903:Smell; D055549:Volatile Organic Compounds / Q000652:urine
D014408:Biomarkers, Tumor; D055549:Volatile Organic Compounds