Canine olfactory detection of lung cancer in human urine: a step forward in dog learning and training

Human lung cancer is the leading cause of cancer-related deaths in the world because early diagnosis is difficult. Three female family dogs (2 Belgian Malinois and 1 mixed-breed dog) aged 2.5–6 yrs are currently being trained by clicker training method (operant conditioning) with positive reinforcement (food) to scent and recognize urine of people with lung cancer (LCa). In this first learning phase, dogs were thought to discriminate between urine from individuals with LCa and urine from healthy controls, both recruited in the European Institute of Oncology (IEO) of Milan. The dogs were thought to signal a cancer urine, by sitting in front of it, among samples containing only one LCa urine and three to five randomly selected controls. Data was analyzed using nonparametric statistics and regression models (SPSS, version 22.0 for Windows; SPSS Inc., Chicago, IL, USA). Dogs showed an increasing trend in the percentage of correct choices across the training period. The factors dog, number of daily session and time of training emerged as robust predictors of a dog’s correct choice (p<0.05). These findings provide information which are useful in improving rational and effective dog training strategies for olfactory detection of lung cancer on urine samples. Moreover, they would suggest that LCa gives a VOCs-related odor signature to urine. If the next phases of this study confirm these results, then the integration of sniffer dogs into research strategies will turn out to be a useful tool for early diagnosis of lung cancer and improved patient survival.