ABSTRACT
BACKGROUND: Lung carcinoma is one of the most common malignancies worldwide. At present, unfortunately, there are no markers that would allow early identification of this tumor in the preclinical or early clinical stage. The use of sniffer dogs has been reported to show some promise in early diagnosis of this type of cancer Aim: This study aimed to evaluate the possibility of utilizing changes in the heart rate of sniffer dogs (which increases when finding a positive sample) in tumor detection. METHODS: This double-blinded pilot study included two sniffer dogs. A chest strap was fastened on the dog's chests for heart rate monitoring while they were examining samples and heart rate was recorded. Test parameters (sensitivity, specificity, positive and negative predictive values) were then calculated, evaluating performances based on (i) the dog's indications according to their training and (ii) the changes in their heart rates. RESULTS: Calculation according to the dog's indications revealed an overall sensitivity of 95.2% accompanied by a specificity of 81.8%, a PPV of 93.7%, and an NPV of 85.7%, respectively. These results were not significantly different from those evaluated by heart rate; heart rate monitoring was, however, burdened with a relatively high proportion of invalid experiments in which heart rate measurement failed. When the method of calculation was changed from rounds to individual samples, the test parameters further increased. CONCLUSIONS: This pilot study confirmed the hypothesis that heart rate increases in trained sniffer dogs when encountering samples from tumor-positive patients but remains unchanged when only negative samples are present. The reliability of results based on heart rate increase is similar to that obtained by a dog's indications and, if the limitation represented by technical issues is overcome, it could serve as a valuable verification method.
ABSTRACT
BACKGROUND: Lung cancer is one of the most often diagnosed tumours in the world with the highest mortality. A major problem and reason for the high mortality from lung cancer is its diagnosis in the late stages. The main goal of preventing lung cancer deaths is early detection in the early stages and accurate diagnosis, which must be followed by targeted treatment. Nevertheless, even top diagnostic techniques do not have the same accuracy and sensitivity as a dog's sense of smell. METHODS: The study aims to present the results of olfactometric detection of lung cancer using the smell of dogs in unblinded, single-blinded and double-blinded studies. 115 serum samples or breath from patients with lung cancer and 101 samples from healthy people were used for the training. The group consisted of women and men of Indo-European origin, mostly from the Moravian-Silesian region in Czech Republic. Two dogs were selected for the study. RESULTS: In the case of tumor detection in the form of unblinded tests, Bugs had a sensitivity of 91% and a specificity of 92%. Boolomo had a sensitivity of 89% and a specificity of 81%. For single-blinded tests, Bugs had a sensitivity of 71%. The sensitivity of Boolomo was set at 90%. After meeting the sensitivity limit of 70%, dogs were included in the double-blinded studies. The highest accuracy was set at 68% for Bugs, 83% for Boolomo. CONCLUSION: When a tumour is diagnosed in the late stages, it is a great burden on both the health and economic systems of the state. Unfortunately, there is still no suitable screening test to detect the tumour at an early stage, so any other method of detection seems desirable. Trained dogs are used in many fields, why not also in medicine and the diagnosis of tumours?
