Researchers at the University of East Anglia have created a urine test for prostate cancer which can tell how serious the disease is.
The test could be used for men who have suspected prostate cancer, to find out how aggressive it is, without having to carry out an invasive biopsy.
The majority of cancers develop slowly and do not need to be treated during a man's lifetime.
Dr Dan Brewer, who led the project at UEA's Norwich Medical School, said it could help prevent patients getting treatment they do not need.
He said: "While prostate cancer is responsible for a large proportion of all male cancer deaths, it is more commonly a disease men die with rather than from.
"Therefore, there is a desperate need for improvements in diagnosing and predicting outcomes for prostate cancer patients to minimise over-diagnosis and overtreatment whilst appropriately treating men with aggressive disease, especially if this can be done without taking an invasive biopsy.
"Invasive biopsies come at considerable economic, psychological and societal cost to patients and healthcare systems alike."
The tested was trialled using urine samples from 207 patients at the Norfolk and Norwich University Hospital.
It was able to correctly detect the people who had prostate cancer, and suggest which of the patients would need a biopsy and those for whom it would be unnecessary based on the seriousness of the disease.
According to Dr Brewer the test could "reduce the number of unnecessary biopsies by 35%".
The study was part-funded by Movember, a charity best known for its fundraising efforts every November where men are encouraged to grow a moustache.
Paul Villanti, executive director of programmes at Movember, said they were "proud to have supported" the test's development.
He added: "Having non-invasive tests which can accurately show how aggressive a man’s prostate cancer is not only reduces the number of men having to undergo painful biopsies, but also ensures that the right course of treatment for the patient is selected more quickly."
The full study has been published in the journal Cancers today.