Prostate cancer is the fourth most common cancer worldwide and the most common cancer among men in the UK. In its early stages, it is often symptomless, but more advanced prostate cancers may cause symptoms such as blood in the urine, difficulty urinating, bone pain and weight loss. Current screening for prostate cancer involves testing a blood sample for elevated levels of prostate-specific antigen (PSA). However, many men who have raised PSA levels do not have prostate cancer and go on to receive unnecessary tissue biopsies and magnetic resonance imaging (MRI) scans. According to a UK study published in December, a new algorithm that predicts an individual’s prostate cancer risk based on genetic factors may lead to more targeted screening and diagnostic testing. If this predictive tool becomes widely implemented, GlobalData epidemiologists expect diagnosed incident cases of prostate cancer in the UK to increase.
The study, conducted by Nyberg and colleagues and published in the Journal of Clinical Oncology, developed a genetic risk model based on data from the UK Genetic Prostate Cancer Study, a cohort of more than 16,600 men diagnosed with prostate cancer between 1993 and 2017. Genetic makeup and family history are the main risk factors for prostate cancer, and inherited, albeit rare, faulty variants of several genes (for example BRCA2 and HOXB13) are associated with a moderate-to-high risk of prostate cancer. Furthermore, there is a cluster of more common genetic variants that act in concert to increase risk. Thus, the authors developed a model predicting incident prostate cancers from information on rare pathogenic variants, a polygenic score based on 268 low-risk variants, and cancer family history and validated the model in an independent cohort of 170,850 prospectively followed men. The majority (86%) of incident prostate cancers in the validation cohort occurred in the half of men with the highest predicted risks. These results suggest it may be possible to target screening and diagnostic tests to high-risk subgroups, such as men with certain combinations of high-risk genetic variants.
In the UK, GlobalData epidemiologists forecast that diagnosed incident cases of prostate cancer will increase from 55,050 cases in 2022 to just over 60,100 cases by 2028. This novel prediction tool for prostate cancer risk will allow for earlier and more targeted cancer diagnosis among high-risk men. If it becomes widely implemented in the UK, as the authors intend, GlobalData epidemiologists expect incident cases to increase above those currently forecast as more cases are diagnosed earlier. Early detection will lead to earlier treatment and, ideally, better outcomes and survival among prostate cancer patients. It will also reduce unnecessary testing among men at low risk for prostate cancer.
The next step is to expand CanRisk, a tool currently used to predict breast and ovarian cancer risk, to include a prediction for prostate cancer risk using this model. Because the authors developed the model using data from men of European ancestry, the next steps also include validating it in men of other ethnicities. GlobalData epidemiologists recommend validation of this tool in additional large cohorts and continued monitoring of trends in prostate cancer.