A simple genetic test could improve diagnosis of the most common cancer to affect men in the UK, according to researchers.
Scientists believe the test, which spots problem cells that can appear healthy under a microscope, will help identify prostate cancers that have been missed in routine check-ups.
Crucially, the procedure could prevent patients from undergoing repeated invasive investigations which can be unpleasant and carry a risk of serious infection.
Scientists from the universities of Edinburgh and St Andrews led research into the new test, being developed with a diagnostics firm.
Currently, men who produce elevated results in a blood test known as the Prostate-Specific Antigen (PSA) test are typically referred for an initial biopsy so that a tissue sample can be obtained for analysis.
In some cases however, the initial biopsy will produce a negative or inconclusive result, sparking fears cancer is present but has been missed. In those cases, the men would typically undergo a second biopsy, which can be a painful and risky procedure.
The new procedure tests DNA extracted at the initial biopsy and looks for particular changes in genes, which could suggest cancer is present. The test works by recognising the "halo" of cells which forms around a prostate tumour. The cells, which can appear normal, actually contain silenced genes that turn off the cell's natural protection against tumour growth.
Researchers said that by identifying genetic changes in these halo cells, they can tell that a patient is more likely to have a tumour, even if their tissue sample shows no cancerous cells.
If the new test produces a positive result, the patient will be sent for a second biopsy, as normal. However, if the result of the test is negative, the patient will not need to undergo the difficult second biopsy he would otherwise have had to experience and his health is simply monitored over time.
Details of the study have been published in The Journal of Urology.