Accuracy of canine scent detection of non–small cell lung cancer in blood serum

Abstract

Context: Early detection provides the best opportunity for lung cancer survival; however, lung cancer is difficult to detect early because symptoms do not often appear until later stages. Current screening methods such as x-ray and computed tomographic imaging lack the sensitivity and specificity needed for effective early diagnosis. Dogs have highly developed olfactory systems and may be able to detect cancer in its primary stages. Their scent detection could be used to identify biomarkers associated with various types of lung cancer. Objective: To determine the accuracy of trained beagles’ ability to use their olfactory system to differentiate the odor of the blood serum of patients with lung cancer from the blood serum of healthy controls. Methods: Over the course of 8 weeks, operant conditioning via clicker training was used to train dogs to use their olfactory system to distinguish blood serum from patients with malignant lung cancer from blood serum from healthy controls in a double-blind study. After training, non–small cell lung cancer and healthy control blood serum samples were presented to the dogs, and the sensitivity and specificity of each dog were analyzed. Results: Four dogs were trained for the study, but 1 was unmotivated by training and removed from the study. Three dogs were able to correctly identify the cancer samples with a sensitivity of 96.7%, specificity of 97.5%, positive predictive value of 90.6%, and negative predictive value of 99.2%. Conclusion: Trained dogs were able to identify non–small cell lung cancer samples from healthy controls. The findings of this study provide a starting point for a larger-scale research project designed to explore the use of canine scent detection as a tool for cancer biomarkers.