Measuring a type of genetic variation in the blood of men with prostate cancer could help predict how their disease will develop, according to US research.

If the results are replicated in further studies, measuring such variation could help tell doctors how likely a relapse after surgery will be, and also whether the disease is likely to be aggressive or slow-growing.

The research, carried out by scientists from University of Pittsburgh School of Medicine, measured the number of so-called 'copy number variations' (CNVs) in prostate tissue, in the healthy prostate tissues surrounding a tumour, and in the blood of patients with prostate cancer.

CNVs are regions of a person's DNA where sections of the genetic material are either duplicated or missing. Different individuals have different degrees of CNV.

The researchers then compared the degree of variation in each sample to clinical details of the patients' disease, such as how likely it was to return.

The research, to be published in The American Journal of Pathology, indicates that measuring CNVs in both tumours and surrounding healthy tissues can be used to predict how prostate cancer will progress.

The scientists analysed 238 samples from men who had had surgery to remove of all or part of their prostate. These included 104 tumour samples, 85 blood samples and 49 samples of normal prostate tissues adjacent to a tumour.

They found that CNVs from tumour samples correctly predicted 73 per cent of cases that relapsed. Measuring CNVs from tissue samples surrounding the prostate tumour correctly predicted 67 per cent of cases that relapsed.

Measuring CNV in blood samples correctly predicted 81 per cent of the cases that relapsed.

Latest Cancer Research UK statistics show that the number of men diagnosed with prostate cancer in the UK has risen above 40,000 for the first time, largely due to increased use of PSA testing. But working out which of these cases will or will not need treating remains a major challenge.

Professor Malcolm Mason, Cancer Research UK's prostate cancer expert, said the research was "interesting and encouraging", but that more work was required to work out what was causing the link between CNVs and prostate cancer.

"If confirmed in a larger number of samples, this research might teach us something about the biology of prostate cancer and maybe other cancers," he said.

"The results could also help develop a test to distinguish slowly growing prostate cancers from more aggressive ones - something we urgently need to improve things for men diagnosed with the disease. But a lot more work is needed before we know whether or not this will be possible," he added.

Source: CRUK