Prostate cancer risk prediction algorithm could help target testing at men at greatest risk

Cambridge scientists have created a comprehensive tool for predicting an individual’s risk of developing prostate cancer, which they say could help ensure that those men at greatest risk will receive the appropriate testing while reducing unnecessary — and potentially invasive — testing for those at very low risk.

CanRisk-Prostate, developed by researchers at the University of Cambridge and The Institute of Cancer Research, London, will be incorporated into the group’s CanRisk web tool, which has now recorded almost 1.2 million risk predictions. The free tool is already used by healthcare professionals worldwide to help predict the risk of developing breast and ovarian cancers.

Prostate cancer is the most common type of cancer in men. According to Cancer Research UK, over 52,000 men are diagnosed with the disease each year and there are more than 12,000 deaths. Over three-quarters (78%) of men diagnosed with prostate cancer survive for over ten years, but this proportion has barely changed over the past decade in the UK.

Testing for prostate cancer involves a blood test that looks for a protein known as a prostate-specific antigen (PSA) that is made only by the prostate gland; however, it is not always accurate. According to the NHS website, around three in four men with a raised PSA level will not have cancer. Further tests, such as tissue biopsies or MRI scans, are therefore required to confirm a diagnosis.

Professor Antonis Antoniou from the Department of Public Health and Primary Care at the University of Cambridge said: “Prostate cancer is the most common cancer in men in the UK, but population-wide screening based on PSA isn’t an option: these tests are often falsely positive, which means that many men would then be biopsied unnecessarily. Also, many prostate tumours identified by PSA tests are slow-growing and would not have been life-threatening. The treatment of these tumours may do more harm than good.

“What we need is a way of identifying those men who are at greatest risk, allowing us to target screening and diagnostic tests where they are most needed, while also reducing the harms for those men who have low risk of the disease. This is what CanRisk-Prostate aims to do. For the first time, it combines information on the genetic makeup and prostate cancer family history, the main risk factors for the disease, to provide personalised cancer risks.”

Prostate cancer is one of the most genetically determined of common cancers. Inherited faulty versions of the BRCA2, HOXB13 and possibly BRCA1 genes are associated with moderate-to-high risk of prostate cancer, though such faults are rare in the population. In addition, there are several hundred more common genetic variants that each confer a lower risk, but in aggregate they act like ‘volume control’ that moderate or increase the prostate cancer risk.

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