Urine Diagnostic Test Created for Urological Malignancies

A urine diagnostic test has been created for prostate cancer that could mean that invasive diagnostic procedures that men currently undergo eventually become a thing of the past.

The system developed composed of a gas chromatography column coupled to a metal-oxide gas sensor (GC-sensor) and a computer algorithm or pipeline. The pipeline involves chromatogram alignment, data transformation and feature selection algorithms in order to identify the features that best differentiate the medical condition.

Scientists at the University of Liverpool (UK) working with colleagues from other British institutions carried out a pilot study that included 155 men presenting to urology clinics. Of this group, 58 were diagnosed with prostate cancer, 24 with bladder cancer and 73 with hematuria or poor stream without cancer. Aliquots of 0.75 mL of fresh urine were stored in septum-topped glass headspace vials (Supelco, Sigma Aldrich; Dorset, UK) and frozen at −20 °C.

The gas chromatography sensor system is known as the Odoreader. The GC-sensor was composed of a Clarus 500 gas chromatography (GC) oven (Perkin Elmer, Waltham, MA, USA) fitted with a commercially available capillary column. The injection port of the GC was fitted with a 1 mm quartz liner and heated to a temperature of 150 °C. The volatile organic compounds (VOCs) present in the headspace of the urine mixture are passed through the GC, where they are separated according to their molecular weight, boiling point, polarity and chemical functionality.

The team found significant separation between prostate cancer and control samples, bladder cancer and controls and between bladder and prostate cancer samples. For prostate cancer diagnosis, the GC/ support vector machine (SVM) system classified samples with 95% sensitivity and 96% specificity after leave-one-out cross-validation (LOOCV). For bladder cancer diagnosis, the SVM reported 96% sensitivity and 100% specificity after LOOCV, while the double cross-validation reported 87% sensitivity and 99% specificity, with SVM showing 78% and 98% sensitivity between prostate and bladder cancer samples.

Chris S. J. Probert, MD, FRCP, FHEA, a professor of gastroenterology, and the senior author of the study, said, “There is an urgent need to identify these cancers at an earlier stage when they are more treatable as the earlier a person is diagnosed the better. After further sample testing the next step is to take this technology and put it into a user friendly format. With help from industry partners we will be able to further develop the Odoreader, which will enable it to be used where it is needed most; at a patient's bedside, in a doctor's surgery, in a clinic or walk-in center, providing fast, inexpensive, accurate results.” The study was published on February 11, 2016, in the Journal of Breath Research.

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University of Liverpool
Supelco
Perkin Elmer