INTRODUCTION: The use of signal dogs for cancer detection is not yet routinely performed,but dogs and their powerful olfactory system have proven to be a unique and valuable tool for many lineages and are beginning to be incorporated into medical practice. This method has great advantages; the dog can detect a tumour in the human body already in preclinical stages, when the patient has no symptoms yet. The identification of cancer biomarkers to enable early diagnosis is a need for many types of cancer, whose prognosis is strongly dependent on the stage of the disease. However, this method also has its various pitfalls that must be taken into account. AIM: The aim of the study was to identify and highlight the factors that affect the level of detection accuracy, but also the conditions associated with olfactometric diagnosis. METHODS: The study included 48 dogs and 48 handlers, that were part of the training between 2016 and 2023.All those who started olfactometry training and remained in training for at least one year were included in the study. The dogs ranged in age from 8 months to 12 years and were of different races and sexes. After long-term observation, a qualitative analysis was performed and factors that may play a role in the early detection of the disease were listed. RESULTS: The results of the search for the different factors have been compiled into two groups, focussing on the actual handling of the patient biological sample from collection, processing, storage until transport, preparation of the sample,and detection. Focus on the actual work and behaviour of the dog and handler. CONCLUSION: There are many factors; however, it is worth addressing them because the canine sense of smell is one of the possible uses as a diagnostic method.

Centre for Epidemiological Research Faculty of Medicine University of Ostrava Ostrava Czech Republic

Czech Centre of Signal Animals Novy Jicin Czech Republic

Department of Epidemiology and Public Health Faculty of Medicine University of Ostrava Ostrava Czech Republic

Department of Pulmonary Vitkovice Hospital Ostrava Czech Republic

Zobrazit více v PubMed

Cometto-Muñiz J.E., Cain W.S. Olfactometry: selecting and presenting odorants. Methods Chem. Neuroanat. 1998;15:227–251.

Horváth G., Andersson H., Nemes S., Bielik Á. Olfactory measurement by the dogs: science or practice? Acta Vet. Hung. 2008;56(4):475–484.

Eis V. 2018. Pachové Práce Služebních Psů. ISBN 978-80-206-1705 7.

Kudlak M., Ali M.M., Whitlow Kirk S., Medalsy N., Yoder H., Bhullar H. Canine scent detection in lung cancer screening. Cureus. 2023;15(5):1–5. doi: 10.7759/cureus.38877. PubMed DOI PMC

Riedlova P., Tavandzis S., Kana J., Tobiasova M., Jasickova I., Roubec J. Olfactometric diagnosis of lung cancer by canine scent – a double-blinded study. Complement. Ther. Med. 2022;64 doi: 10.1016/j.ctim.2022.102800. PubMed DOI

Williams H., Pembroke A. Sniffer dogs in the melanoma clinic? Lancet J. 1989;333(8640):P734. doi: 10.1016/S0140-6736(89)92257-5. PubMed DOI

Jezierski T., Walczak M., Ligor T., Rudnicka J., B B. Study of the art: canine olfaction used for cancer detection on the basis of breath odour. Perspectives and limitations. J. Breath Res. 2015;6(2) 9. PubMed

Ehmann R., Boedeker E., Friedrich U., Sagert J., Dippon J., Friedel G., Walles T. Canine scent detection in the diagnosis of lung cancer: revisiting a puzzling phenomenon. Eur. Respir. J. 2012;39(3):669–676. doi: 10.1183/09031936.00051711. PubMed DOI

Brooks S.W., Moore D.R., Marzouk E.B., Glenn F.R., R H. Anine olfaction and electronic nose detection of volatile organic compounds in the detection of cancer: a review. Cancer Invest. 2015;33(9):411–419. PubMed

Cornu J.N., Cancel-Tassin G., Ondet V., Girardet C., O C. Olfactory detection of prostate cancer by dogs sniffing urine: a step forward in early diagnosis. Eur. Urol. 2011;59(2):197–201. PubMed

McCulloch M., Jezierski T., Broffman M., Hubbard A., Turner K., Janecki T. Diagnostic accuracy of canine scent detection in early- and late-stage lung and breast cancers. Integr. Cancer Ther. 2006;5(1):30–39. doi: 10.1177/1534735405285096. PubMed DOI

Riedlova P., Tavandzis S., Kana J., Ostrizkova S., Kramna D., Krajcir L., Kanova T., Lastikova S., Tomaskova H., Roubec J. Changes in the heart rate of sniffer dogs trained for detection of lung cancer. Diagnostics. 2023;13(15):1–11. doi: 10.3390/diagnostics13152567. PubMed DOI PMC

Junqueira H., Quinn T.A., Biringer R., Hussein M., Smeriglio C., Barrueto L., Finizio J., Huang X.Y.M. Accuracy of canine scent detection of non–small cell lung cancer in blood serum. J. Am. Osteopath. Assoc. 2019;119(7):413–418. doi: 10.7556/jaoa.2019.077. PubMed DOI

Sonoda H., Kohnoe S., Yamazato T., Satoh Y., Morizono G., Shikata K., Morita M., Watanabe A., Morita M., Kakeji Y., et al. Colorectal cancer screening with odour material by canine scent detection. Gut. 2011;60(6):814–819. doi: 10.1136/gut.2010.218305. PubMed DOI PMC

Helton William S. Cephalic index and perceived dog trainability. Behav. Processes. 2009;82(3):355–358. PubMed

Munthe C. Practical applications. Int. Libr. Ethics, Law Technol. 2011;6:133–183. doi: 10.1007/978-94-007-1330-7_6. DOI

Dorothea Johnen, Wolfgang Heuwieser, C F.-T. Canine scent detection—fact or fiction? Appl. Anim. Behav. Sci. 2013;148(3–4):201–208.

Bräuer J., Blasi D. Dogs display owner-specific expectations based on olfaction. Sci. Rep. 2021;11(1):1–10. doi: 10.1038/s41598-021-82952-4. PubMed DOI PMC

Jenkins E.K., DeChant M.T., Perry E.B. When the nose doesn't know: canine olfactory function associated with health, management, and potential links to microbiota. Front. Vet. Sci. 2018;5(MAR) doi: 10.3389/fvets.2018.00056. PubMed DOI PMC

Hall N.J., Wynne C.D.L. Odor mixture training enhances dogs' olfactory detection of home-made explosive precursors. Heliyon. 2018;4(12) doi: 10.1016/j.heliyon.2018.e00947. PubMed DOI PMC