Prostate cancer is a major killer
Scientists have found a potential new way to assess whether prostate cancer is aggressive.
They have found tiny bubbles of fat in the urine may hold the key information needed to decide what type of treatment the patient needs.
If prostate cancer is aggressive it requires urgent treatment, but this is not appropriate for patients with slow-growing forms of the disease.
The study appears in Cancer Research UK's British Journal of Cancer.
Prostate cancer is the most common cancer in men in the UK.
Each year around 34,000 men are diagnosed with the disease, and around 10,000 die from it.
But while the disease can be a killer, in its more benign form it often requires nothing other than close monitoring and the patient often eventually dies from another, unrelated condition.
Until now, researchers have used levels of proteins, like prostate specific antigen (PSA), produced by cancer cells to try to spot the aggressive tumours.
But this can throw up inaccurate results, and lead to people unnecessarily undergoing treatment which can have long-term side effects, such as incontinence and impotence.
Direct from tumour
The latest work focused on fatty capsules called exosomes that are flushed out of the body in the urine.
Scientists found that in patients with prostate cancer exosomes contain molecules that come directly from the tumour itself.
These molecules, which contain a type of genetic material called RNA, can be used to figure out which genes are turned on and off in the cancer - and thus whether it is aggressive or not.
The researchers, led by Dr Jonas Nilsson, from the VU University Medical Centre in Amsterdam, hope the discovery will enable them eventually to develop a more effective test for aggressive tumours.
John Neate, of the Prostate Cancer Charity, said the study was a step towards finding a reliable way to identify aggressive forms of the disease.
But he warned it was a small study, and scientists would need to examine exosomes from a larger number of men before they could assess the reliability of the technique.
He also said the need to massage the prostate to increase the likelihood that the relevant molecules were released into the urine might reduce its acceptability as a mass screening tool.
Mr Neate added: "Nevertheless, this approach holds promise as a non-invasive test of malignancy that could help men and their doctors in the future.
"Possibly the most significant research question in prostate cancer is how to distinguish early, and with confidence, the potentially life-threatening prostate tumours from the slow growing form of the disease.
"Then treatments could be refined and concentrated on the aggressive cancers where the benefits of treatment far outweigh the risk of side-effects, which can seriously affect a man's quality of life."