Article Text

Download PDFPDF

Colorectal cancer screening with odour material by canine scent detection
  1. Hideto Sonoda1,6,
  2. Shunji Kohnoe1,6,
  3. Tetsuro Yamazato2,
  4. Yuji Satoh3,
  5. Gouki Morizono4,
  6. Kentaro Shikata5,
  7. Makoto Morita6,
  8. Akihiro Watanabe6,
  9. Masaru Morita1,
  10. Yoshihiro Kakeji1,
  11. Fumio Inoue4,
  12. Yoshihiko Maehara1
  1. 1Department of Surgery and Science, Kyushu University at Fukuoka, Fukuoka, Japan
  2. 2Department of Internal Medicine, Arita Kyoritsu Hospital at Arita, Saga, Japan
  3. 3St. Sugar Cancer Sniffing Dog Training Center at Minamibousou, Chiba, Japan
  4. 4Department of General Surgery, Arita Kyoritsu Hospital at Arita, Saga, Japan
  5. 5Department of Internal Medicine, Fukuoka Dental College Hospital at Fukuoka, Fukuoka, Japan
  6. 6Department of General Surgery, Fukuoka Dental College Hospital at Fukuoka, Fukuoka, Japan
  1. Correspondence to Dr Hideto Sonoda, Department of Surgery and Science Graduate School of Medicine Kyushu University 3-1-1 Midashi,Higashi-ku, Fukuoka 812-8582, Japan; hsonoda{at}


Objective Early detection and early treatment are of vital importance to the successful treatment of various cancers. The development of a novel screening method that is as economical and non-invasive as the faecal occult blood test (FOBT) for early detection of colorectal cancer (CRC) is needed. A study was undertaken using canine scent detection to determine whether odour material can become an effective tool in CRC screening.

Design Exhaled breath and watery stool samples were obtained from patients with CRC and from healthy controls prior to colonoscopy. Each test group consisted of one sample from a patient with CRC and four control samples from volunteers without cancer. These five samples were randomly and separately placed into five boxes. A Labrador retriever specially trained in scent detection of cancer and a handler cooperated in the tests. The dog first smelled a standard breath sample from a patient with CRC, then smelled each sample station and sat down in front of the station in which a cancer scent was detected.

Results 33 and 37 groups of breath and watery stool samples, respectively, were tested. Among patients with CRC and controls, the sensitivity of canine scent detection of breath samples compared with conventional diagnosis by colonoscopy was 0.91 and the specificity was 0.99. The sensitivity of canine scent detection of stool samples was 0.97 and the specificity was 0.99. The accuracy of canine scent detection was high even for early cancer. Canine scent detection was not confounded by current smoking, benign colorectal disease or inflammatory disease.

Conclusions This study shows that a specific cancer scent does indeed exist and that cancer-specific chemical compounds may be circulating throughout the body. These odour materials may become effective tools in CRC screening. In the future, studies designed to identify cancer-specific volatile organic compounds will be important for the development of new methods for early detection of CRC.

  • Dog
  • canine scent detection
  • colorectal cancer
  • breath sample
  • stool sample
  • diagnosis
  • breath tests
  • screening
  • stool markers

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: and

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding This study was funded by Fukuoka Dental College.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the institutional review boards at Fukuoka Dental College and Arita Kyoritsu Hospital and all subjects provided written informed consent.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Linked Articles

  • Digest
    Emad El-Omar Alexander Gerbes William Grady