Electronic Nose Sniffs Out Prostate Cancer
Sensor device can distinguish between cancer and BPH
According to an article in the July 2014 issue of the Journal of Urology, clinicians may someday be able to make early diagnoses of prostate cancer by smell.
Researchers in Finland have developed a noninvasive technique that can detect prostate cancer using an electronic nose. In a proof-of-principle study, the eNose successfully discriminated between prostate cancer and benign prostatic hyperplasia (BPH) by “sniffing” urine samples. The results were comparable with those provided by prostate specific antigen (PSA) testing.
eNoses are routinely used in food and agricultural quality control and in military applications. The eNose used in the new study is a device that consists of a cluster of nonspecific sensors. When the device is exposed to a sample, it produces a profile or “smell print.”
“eNoses have been studied in various medical applications, including early detection of cancer, especially from exhaled air,” said lead investigator Niku Oksala, MD, PhD, DSc. “However, exhaled air is a problematic sample material since it requires good cooperation and technique from the patient and immediate analysis, while urine is simple to obtain and store, and is therefore more feasible in clinical practice. Preliminary data suggested that detection of urologic malignancies from urine was possible. Our own preliminary results on prostate cancer cells encouraged us to launch this prospective clinical study.”
The ChemPro 100–eNose (Environics Inc.) was tested on 50 patients who had biopsy-confirmed prostate cancer and on 15 patients with BPH. Both groups were scheduled for surgery. All of the patients provided pre-surgery urine samples. In addition, those with BPH provided samples 3 months after surgery to be used as a pooled control-sample population. Patients with prostate cancer underwent robotic-assisted laparoscopic radical prostatectomy, whereas the group with BPH underwent transurethral resection of the prostate.
The results of the study confirmed that, using urine samples, the eNose is able to distinguish prostate cancer from BPH. The device achieved a sensitivity of 78%, a specificity of 67%, and an area under the curve (AUC) concentration of 42.0.
“PSA is known to correlate positively with prostate volume, which is a potential source of diagnostic error when comparing prostate cancer with benign disease,” Oksala said. “According to our current analysis, prostate volume did not affect the eNose results, potentially indicating high specificity of our sensor array to cancer. We also studied whether the eNose signal correlates with the size of the tumor. No such correlation was found. Further studies are now warranted to enhance current technology and to identify the molecules behind the distinct odors.”
Source: Medical Xpress; May 1, 2014.