eNose device shows promise in detecting prostate cancer

Results from a study presented at the 2021 American Urologic Association Annual Meeting, found promising diagnostic performance of the electric nose (eNose) in detecting volatile organic compounds (VOCs) in urinary samples of patients with prostate cancer.¹

In comparison to the cohort of highly trained dogs, the eNose instrument was found to have sensitivity (SE) of 85.2% (95% CI, 76.1-91.9, 13 wrong cases out of 174) and specificity (SP) of 79.1% (95% CI, 69.0-87.1, 18 wrong cases out of 174).

“The diagnosis of prostate cancer is currently still a great challenge. Prostate biopsy has a detection rate of 30% to 35% at the first biopsy. For this reason, the study of alternative diagnostic methods is essential,” said author Gian Luigi Taverna, MD, head of the urology department at Humanitas Mater Domini, Castellanza, Varese, Italy.

VOCs in biological fluids have become known as possible non-invasive biomarkers in prostate cancer. Although the use of highly trained dogs in a clinical setting is intriguing, the actual implementation presents limits such as extensive training, difficulty in introducing dogs to hospital protocols, a need for highly qualified centers, and the short lifespan of a dog as well as the sustainability and reproducibility on a large scale.

In this ongoing, double-blind, prospective cohort study, the eNose was implemented as an alternative instrument that mimicked the nasal capabilities of highly trained dogs. The performance of this technology was then compared with canine performance to assess the instrument’s efficacy and verify the mimicking capability.

During the training phase of the study (2016-2020), eNose tested 290 prostate cancer urine samples and 244 control urine samples. After analysis, the results of this phase were not considered for statistical purposes.

During the blind phase of this study, urine samples were collected from a prostate cancer group (men with biopsy-proven prostate cancer at any stage and grade) and a control group (healthy men and women affected by different benign and malignant pathologies), in which each patient gave 2 30cc samples. Of the 174 subjects who participated in the study, 88 (50.6%) were in the prostate cancer group and 86 (49.4%) were in the control group.

The first samples were given to the military veterinary center of the Italian Ministry of Defense in Grosseto (CEMIVET), to be tested by 2 German Shepherd Explosion Detected Dogs that had been trained to identify prostate cancer VOCs. The next samples were given to the Natta Institute of Politecnico di Milano to be tested by eNose.

Dog 1 achieved an SE of 97.7% (95% CI 92.0-99.7, 2 wrong out of 174) and an SP of 98.8% (95% CI 97.7-100, 1 wrong case out of 174). Dog 2 achieved an SE of 96.6% (95% CI 90.4-99.3, 3 wrong cases out of 174) and an SP of 98.8% (95% CI 93.7-100, 1 wrong case out of 174). Although the eNose performed at lower rates of efficacy, “The diagnostic accuracy of the eNose for specific prostate cancer VOCs in urine samples is high, promising, and susceptible to further improvement,” said the study’s investigators.

The authors suggest further research in this topic area, as it is the first project to address the issues of sensor reproductivity and drift over time. Larger-scale studies, for example, could assess the potential of eNose to validate its application in diagnostic prostate cancer nomograms.

“It is clear that the more data we have, the more we expect the instrument to learn and to become better in classifying samples…We are very happy with the results that we achieved,” concluded author Laura Cappelli, department of chemical engineering, Politecnico di Milano University.

In a news release regarding the study,² Stacy Loeb, MD, MSc, a professor of urology and population health at NYU Langone Health and the Manhattan Veterans Affairs Medical Center, commented, “We all know the sense of smell is a superpower for dogs. Seeing this superpower put to the test against advanced technology is fascinating. In a world full of technology, it appears dogs are better able to naturally screen for prostate cancer than our most advanced technology. Hopefully science and technology can learn more from them in the near future and finally catch up.”

References

1. Taverna GL, Zanoni M, Vota P, et al. A double blind, prospective study for prostate cancer diagnosis in urine sample: accuracy of the electronic nose compared to highly trained dogs. Paper presented during the 2021 American Urological Association Annual Meeting; September 10-13, 2021; virtual. Abstract MP30-17

2. Canines ‘out-sniff’ technology in detecting prostate cancer in men. News release. American Urological Association. September 10, 2021. Accessed September 13, 2021. https://www.prnewswire.com/news-releases/canines-out-sniff-technology-in-detecting-prostate-cancer-in-men-301373237.html