A large-scale study has found huge variation between GP practices on whether they are likely to pick up prostate cancer using a blood test.
The University of Exeter led a study which 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 published in the British Journal of General Practice and funded by Cancer Research UK, and, has 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 evidence shows that 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 has 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.
Professor Gary Abel, from the University of Exeter, led the study with support from NIHR PenARC. He 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 collaborators from the Universities of Manchester and Newcastle, and University College London, 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.
Lead author Dr Sam Merriel, NIHR Academic Clinical Lecturer at the University of Manchester and a practicing GP, said:
“Referral from GPs is currently the main route by which men are diagnosed with prostate cancer. The PSA blood test is the only test available for this purpose and has some well-known limitations. Inconsistencies in local, regional, and national guidance mean it is really down to individual GPs to make decisions on which patients to test, how often to test, and what PSA thresholds warrant urgent referral for suspected cancer. These inconsistencies may be contributing to the variation in whether GPs are detecting prostate cancer in patients who do not have symptoms.”
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.”
This research was supported by NIHR Applied Research Collaboration South West Peninsula (PenARC) and NIHR Manchester Biomedical Research Centre.
The paper is titled ‘Factors affecting prostate cancer detection through asymptomatic prostate-specific antigen testing in primary care in England: evidence from the 2018 National Cancer Diagnosis Audit’, and is published in the British Journal of General Practice.