Year : 2011 | Volume
: 27 | Issue : 3 | Page : 430--431
Olfactory detection of prostate cancer by dogs sniffing urine: A step forward in early diagnosis
Manoj Kumar, Swarnendu Mandal, Apul Goel
Department of Urology, CSM Medical University (Upgraded King George's Medical College), Lucknow, Uttar Pradesh, India
Department of Urology, CSM Medical University (Upgraded King George«SQ»s Medical College), Lucknow, Uttar Pradesh
|How to cite this article:|
Kumar M, Mandal S, Goel A. Olfactory detection of prostate cancer by dogs sniffing urine: A step forward in early diagnosis.Indian J Urol 2011;27:430-431
|How to cite this URL:|
Kumar M, Mandal S, Goel A. Olfactory detection of prostate cancer by dogs sniffing urine: A step forward in early diagnosis. Indian J Urol [serial online] 2011 [cited 2020 May 27 ];27:430-431
Available from: http://www.indianjurol.com/text.asp?2011/27/3/430/85461
Serum Prostate Specific Antigen is the most widely used biomarker for detection of cancer prostate (PCa).Volatile organic compounds (VOCs) in the urine have been proposed as alternative biomarkers.  The authors through this study tried to determine if some VOCs in urine could result in specific odor associated with PCa that could be detected by a specially trained dog. They conducted a double-blind study to check the ability of the dog to detect PCa by sniffing urine.
A dog was trained by a professional and dedicated team to discriminate between urine from individual with PCa from that of control. The dog was taught to sit in front of sample of urine recognized as cancer. The study included a "training phase" where the dog was conditioned to detect VOCs and a "testing phase" where the dog's ability to detect cancer was checked. In case of success (dog sitting in front of PCa urine sample), the result was classified as a true positive and the controls as true negatives, and the next cancer sample was tested. In case of mistake (dog sitting in front of control urine sample), the control sample was classified as false positive and the cancer sample as a false negative. Thirty-three runs were conducted during the double-blind testing phase. In 30 cases, the dog sat in front of the cancer sample. In three runs, the dog sat in front of a control sample. In these three cases, the control samples incorrectly classified were considered false positives, and the three cancer cases were considered false negatives. During the testing phase, the dog correctly classified 60 samples out of 66. The three patients who provided the urine samples that were classified as false positive underwent a new biopsy, and one was diagnosed with PCa. The sensitivity and specificity of the dog for detecting VOCs in the urine was 91% for both.
Specific VOCs are present in the urine of patients with PCa. Previous work suggests that dogs can be trained to smell urine and recognize lung, bladder and breast cancer with various success rates.  The scientific basis of this ability of dogs to detect the odor signature of cancer is believed to be linked to the VOCs produced by malignant cells.  Basic research studies have established that during tumor growth, protein changes in malignant cells lead to per-oxidation of the cell membrane components and produce VOCs that can be detected in urine.  This study shows for the first time that, regularly trained by a dedicated team, a dog can distinguish a PCa urine sample among controls with powerful results. These preliminary data reflect the existence of a potential odor signature of PCa that may correspond to one or multiple VOCs. These molecules remain unknown for the moment and should be assessed by specific gas chromatography/mass spectrometry analysis. To date, metabolomics studies have only individualized sarcosine as a potential biomarker for PCa.  This study opens the door of VOC detection for PCa diagnosis. Metabolomic studies should complete this approach by determining the volatile molecular signature of PCa.
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