Electronic nose 'can detect cancer'
An electronic nose may be used to sniff out prostate cancer in future following a successful pilot trial.
The ChemPro 100 eNose was used to test the "headspace", or air above samples of patients' urine.
In the study, it proved at least as accurate as the standard PSA (Prostate Specific Antigen) blood test used as the first stage in diagnosing prostate cancer.
Lead scientist Dr Niku Oksala, from Tampere University in Finland, said: "The performance with the eNose matches that of PSA results in previous literature and the results are achieved rapidly and in a completely non-invasive manner.
"PSA is known to correlate positively with prostate volume, which is a potential source of diagnostic error when comparing prostate cancer with benign disease. According to our current analysis, prostate volume did not affect the eNose results, potentially indicating high specificity of our sensor array to cancer."
The history of the test can be traced back to reports in the 1980s of dogs detecting prostate cancer in their owners.
Experimental studies demonstrated that trained sniffer dogs really can smell cancer, but variations in their performance meant they were of little practical help.
Instead scientists have turned to electronic nose technology routinely used in the food industry and agriculture, as well as by the military.
"eNoses have been studied in various medical applications, including early detection of cancer, especially from exhaled air," said Dr Oksala. "However, exhaled air is a problematic sample material since it requires good co-operation and technique from the patient and immediate analysis, while urine is simple to attain and store, and is therefore more feasible in clinical practice.
"Preliminary data suggested that detection of urologic malignancies from urine headspace was possible. Our own preliminary results on prostate cancer cells encouraged us to launch this prospective clinical study."
The eNose consists of a cluster of electronic sensors which respond to odours to provide a distinctive "smell print".
In the trial involving 65 patients with diagnosed prostate cancer and non-cancerous prostate enlargement, it was able to distinguish between the two conditions.
The eNose achieved a "sensitivity" - the ability to detect patients with cancer - of 78%, the scientists reported in the Journal of Urology. It also had a "specificity" - the ability to avoid wrongly picking out patients without cancer - of 67%.