Electronic Nose 'Sniffs Out' Prostate Cancer

Yael Waknine

May 08, 2014

A new "electronic nose" is capable of detecting prostate cancer from a urine sample with nearly 80% accuracy, according to a proof-of-concept pilot study published in the Journal of Urology.

The device, ChemPro 100 eNose (Environics Inc), is still relatively early in development, but experts say it has potential to add to current diagnostic methods, which include screening for prostate-specific antigen (PSA).

The device was put to the test with samples from 50 patients with biopsy-confirmed prostate cancer and 15 patients with benign prostatic hyperplasia (BPH). It detected cancer with a sensitivity of 78%, specificity of 67%, and area under the curve of 0.77.

The researchers say they believe this is the first time that rapid analysis of urine headspace has been shown to differentiate between patients with prostate cancer and patients with symptomatic BPH.

"The performance with the eNose matches that of PSA results in previous literature and the results are achieved rapidly and in a completely noninvasive manner," lead author Niku Oksala, MD, PhD, DSc, from the University of Tampere, Finland, said in a statement.

Inspiration for the device, which uses a cluster of electronic sensors to detect the volatile "smell print" in urine headspace, came from dogs, which have a known ability to sense cancer in their owners. However, canine performance remains inconsistent even after training, and electronic-nose technology, popular in the food industry and agriculture, offers a dependable alternative while maintaining a high level of sensitivity.

Study limitations include a potential treatment effect — in the BPH group, 9 of the 15 patients had provided samples 3 months after undergoing confirmatory transurethral resection of the prostate.

In addition, real-world medicine is practiced on a population that includes men without prostate cancer or symptoms of BPH, and they were not included in this study, as Michael W. Kattan, PhD, from the Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Ohio, points out in an accompanying editorial.

Still, the findings are promising.

"This is a technology that has been under development for some time, and it is encouraging to see this now applied to the early detection of prostate cancer," Nicholas J. Vogelzang, MD, a specialist in genitourinary oncology at the Comprehensive Cancer Centers of Nevada in Las Vegas, told Medscape Medical News. He suggested that if the findings are reproduced and vetted, the e-Nose test could overcome limitations associated with the widely used PSA test. Indeed, the study authors report that prostate volume — a potential source of diagnostic error with use of the PSA — does not appear to affect eNose results. He was not involved in the study.

"The PSA test has well-recognized limitations such that the [US Preventive Services Task Force] has recommended against using it to screen for prostate cancer, despite the absence of other widely available techniques," Dr. Vogelzang added. Another available test, which uses prostate cancer antigen 3 (PCA3), requires the patient to undergo prostatic massage and then a specific urine test, and "although it has reasonable good sensitivity and specificity, it is not widely used," he said.

The eNose test now has to be studied in the clinic and compared with PSA and PCA3 in a blinded manner, he added.

"What we really need is a diagnostic test that outperforms PSA by preferentially detecting clinically relevant cancers. Perhaps further development of this technology, combined with other clinical or radiographic information, may ultimately bring us closer to such a test," Matthew Galsky, MD, told Medscape Medical News

Dr. Galsky, who was also not involved in the study, is associate professor of medicine and director of genitourinary medical oncology at the Icahn School of Medicine, Tisch Cancer Institute at Mount Sinai in New York City.

Such an idea may not be so far-fetched.

"Sniffing the headspace is an excellent approach and I am confident that the accuracy of their test will increase over time", Nir Peled, MD, PhD, from the Davidoff Cancer Center in Petach Tiqva, Israel, told Medscape Medical News.

As previously reported by Medscape Medical News, Dr. Peled has been working with Hossam Haick, PhD, and his team from the Technion Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute in Haifa, Israel, to develop an electronic nose that detects volatile compounds produced by lung cancer cells in a patient's breath.

"In the field of lung cancer, exhaled breath analysis showed an accuracy of 88% to detect lung cancer. Moreover, Prof Haick's device (NaNose) was able to discriminate between subhistology and even between mutations by sniffing the headspace medium," Dr. Peled said.

"In prostate cancer, there is a similar subhistology but different degrees of activity — perhaps once study enrollment is higher, a subanalysis can be done to stratify the accuracy to differ between the Gleason scores," Dr. Peled concluded.

The study was funded by Tampere University Hospital, Elna Kaarina Savolainene's Cancer Research Fund, Seppo Nieminen's Testament Fund, the Tampere Tuberculosis Foundation, and the Finnish Funding Agency for Technology and Innovation. Dr. Vogelzang, Dr. Galsky, and Dr. Peled have disclosed no relevant financial relationships.

J Urol. Published online February 25, 2014. Abstract Editorial


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