Men with the BRCA2 gene fault have an increased risk of prostate cancer and could benefit from PSA (prostate specific antigen) testing* to help detect the disease earlier, according to researchers funded by Cancer Research UK**.
Previous studies have shown that PSA is not a suitable test for screening for prostate cancer in the general population, and this remains the case. There are limitations to the PSA test - including false positives, false negatives and overdiagnosis***.
But new research found that PSA tests were more likely to pick out more serious forms of prostate cancer in men who carry the BRCA2 gene fault than in non-carriers - suggesting these men could benefit from regular PSA testing.
In the study published today (Tuesday) in European Urology, researchers at The Institute of Cancer Research, London, looked at around 1400 men**** and compared those who don't carry the BRCA2 gene fault with those who do.
Men were offered a yearly PSA test and depending on the result, they were either offered a biopsy to confirm their disease and treated if needed or asked to come back the following year.
The researchers found that men who carry the BRCA2 gene fault were almost twice as likely to be diagnosed with prostate cancer than non-carriers.
They also found that carriers were diagnosed at a younger age - an average of 61 compared with 64 in non-carriers.
Importantly, men with the BRCA2 gene fault were diagnosed with more serious tumours - with 77% of men having clinically significant***** disease compared with 40% of non-carriers.
The study wasn't able to look at whether PSA testing reduced the number of men who died from prostate cancer, which is needed to prove the value of screening in any group.
There are many different things that can raise PSA levels, including an enlarged prostate, certain medications, urinary tract infections or recent ejaculation.
And receiving a false positive result can lead to unnecessary worry and unnecessary biopsies.
This research provides more evidence that the BRCA2 fault increases the risk of prostate cancer in men and shows that a better test is needed to diagnose them.
The BRCA1 and 2 genes are linked to an increased risk in breast and ovarian cancer. But it's less well known that the BRCA2 fault also increases the risk of prostate cancer, although we don't know by exactly how much.
Estimates are around 1 in 300 men could be carrying the gene fault, but only some of them will go on to develop prostate cancer.******
Study leader, Professor Rosalind Eeles, Professor of Oncogenetics at The Institute of Cancer Research, London, and Consultant Clinical Oncologist at The Royal Marsden NHS Foundation Trust, said: "For women who undergo genetic testing, options are available to them if they carry a BRCA fault, including preventative surgery and increased screening. But there's no prevention pathway in place if men decide to find out if they're a carrier. Which is why our research is so important.
"Men may get tested for the BRCA fault due to a family history of breast cancer, as they could pass the gene onto their children, which is especially significant if they have daughters. And our research offers this group of men more insight into their own health.
"Based on our results, we would recommend offering men who carry a fault in the BRCA2 regular PSA tests, so that they can be diagnosed and treated earlier."
Professor Charles Swanton, Cancer Research UK's chief clinician, said: "Understanding more about people at higher risk of prostate cancer is an incredibly important area of research.
"Previous studies have shown that PSA is not a suitable test for screening for prostate cancer in the general population. But we still need to understand whether PSA testing would reduce deaths from the disease in any high-risk groups before we make any recommendation.
"All doctors want the best for their patients and don't want to leave any stone unturned, so some may explain the potential risks associated with PSA testing and still recommend this in high-risk groups despite not knowing that it reduces deaths. Men who are worried about their prostate cancer risk or have a family history should discuss it with their doctor."
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For media enquiries contact Eve Gooden in the Cancer Research UK press office on 020 3469 8300 or, out of hours, on 07050 264 059.
Notes to editor:
* The PSA test looks at the level of prostate specific antigen present in the blood. PSA is a protein produced by normal cells in the prostate and also by prostate cancer cells. It's normal to have a small amount of PSA in the blood, and the amount rises slightly as men get older and the prostate gets bigger. A raised PSA level may suggest a problem with the prostate, but not necessarily cancer. Overall, the evidence shows PSA testing doesn't reduce the number of men who die from prostate cancer.
** Page et al. Interim results from the IMPACT study: evidence for PSA screening in BRCA2 mutation carriers. European Urology (2019) DOI:10.1016/j.eururo.2019.08.019
*** Overdiagnosis is when a cancer wouldn't have gone on to cause harm in a person's lifetime; in other words, if the person hadn't been tested, the person would never have known they had cancer.
**** The men were from 65 centres in 20 countries, but the majority of the subjects were Caucasian (97%). The study had around 3000 participants but only 1400 where in the BRCA2 gene fault comparison.
***** NICE guidelines - https://www.nice.org.uk/guidance/ng131/documents/draft-guideline - page 29, line 8
****** Rebbeck T et al, Mutational Spectrum in a Worldwide Study of 29,700 Families with BRCA1 or BRCA2 Mutations, Human Mutations, 2018 May; 39(5) 593-620
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The Institute of Cancer Research, London, is one of the world's most influential cancer research organisations.
Scientists and clinicians at The Institute of Cancer Research (ICR) are working every day to make a real impact on cancer patients' lives. Through its unique partnership with The Royal Marsden NHS Foundation Trust and 'bench-to-bedside' approach, the ICR is able to create and deliver results in a way that other institutions cannot. Together the two organisations are rated as one of the top centres for cancer research and treatment globally.
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Journal
European Urology