Prostate cancer is one of the most common cancers in men and a major cause of cancer-related deaths. Yet it is tricky to diagnose – the commonly used PSA test can result in over- diagnosis and unnecessary further procedures. Now, new research led by the University of Adelaide in Australia promises to improve the accuracy of prostate cancer diagnosis with the help of biomarkers in seminal fluid.

Writing in the journal Endocrine-Related Cancer, the researchers describe how they analyzed seminal fluid samples from 60 men and found small molecules called microRNAs were “surprisingly accurate” at indicating which men had prostate cancer and how severe it was.

The problem with the current PSA (prostate specific antigen) test for prostate cancer is that, while it is very sensitive, it is not highly specific for prostate cancer. For instance, it might be positive for non-cancerous conditions such as prostatic hyperplasia (BPH) and prostatitis.

This results in many unnecessary biopsies and, perhaps more seriously, in substantial over-diagnosis and over-treatment of slow-growing, non-lethal prostate cancers that are probably best left alone and just monitored under a so-called “watchful waiting” regime.

“Biomarkers that can accurately detect prostate cancer at an early stage and identify aggressive tumors are urgently needed to improve patient care,” says lead author Dr. Luke Selth, a Young Investigator of the Prostate Cancer Foundation in the US.