A large-scale study involving UCL researchers has found huge variation between GP practices on whether they are likely to pick up prostate cancer using a blood test.
The study aimed to investigate the proportion of patients whose prostate cancer was identified by using a prostate-specific antigen (PSA) test when patients had no symptoms.
The research, funded by Cancer Research UK and published in the British Journal of General Practice, found that one in five patients with prostate cancer in England are diagnosed after PSA testing when they had no symptoms - fewer than previously thought.
The PSA test is the only test available for prostate cancer in the UK, which is now the most common form of cancer in the UK, with more than 55,000 new patients diagnosed each year. While PSA testing is routinely used where men have urinary symptoms, opinions are divided on whether it should be used where no symptoms are present.
The UK National Screening Committee recommends against a national screening programme of PSA testing in the UK because the benefits are not clear. Some men will live with prostate cancer that will never cause any harm for the rest of their lives. Finding these cancers through screening can lead to overtreatment which has potential side effects like erectile dysfunction and urinary incontinence.
However, men over the age of 50 are able to request a test from their GP, where they have made an informed decision on the risks and benefits for them.
The new study found large variation between GP practices across England in terms of the proportion of men with prostate cancer diagnosed through PSA testing when they do not have symptoms.
The research found no clear explanation for this disparity, although men from deprived areas were less likely to undergo testing, in line with previous research. They are also more likely to develop late stage prostate cancer.
Co-author Nadine Zakkak, from UCL Behavioural Science & Health, said: "This study shows how analysing data on patient populations and their interactions with GPs can help us to understand differences in diagnostic pathways in order to improve care and reduce inequalities."
Co-author Professor Yoryos Lyratzopoulos, also from UCL Behavioural Science & Health, said: "Prostate cancer is common and a major cause of mortality. These large differences in how often patients get tested highlight the need for evidence from high-quality clinical trials to support decisions by both doctors and patients."
Professor Gary Abel, from the University of Exeter, who led the study, said: "We were surprised by the extent of the variation we saw between practices, which speaks to the ongoing lack of clarity around prostate cancer screening in the UK. We know that men from deprived areas are at highest risk of developing late-stage prostate cancer and were less likely to be investigated. It is hard to know what to do when the evidence isn't clear but a more consistent approach to testing people without symptoms is needed to help redress this imbalance."
The team, which included researchers at UCL and the Universities of Exeter, Manchester and Newcastle, analysed more than 9,800 records of men with prostate cancer from the 2018 English National Cancer Diagnosis Audit. The audit asked GPs to revisit records of people who had been diagnosed with cancer to record their symptoms and what tests they were given.
Naser Turabi, director of evidence and implementation at Cancer Research UK, said: "This study highlights variation in the detection of prostate cancer through PSA testing in men with no symptoms. The possibility of a cancer diagnosis can be extremely worrying, so we understand why some men ask for the PSA test. However, the evidence shows that it can cause more harm than good for men who have no prostate cancer symptoms. The UK National Screening Committee is constantly reviewing the best evidence and doesn't currently recommend screening for prostate cancer.
"We're determined to find better ways to detect and treat prostate cancer and we will continue to fund research to improve our understanding and help save lives." Links
