Lynch syndrome increases the risk of several cancer types including bowel cancer, and affects 175,000 people in the UK.
But only 5% of people with the condition know they have it.
According to a new study, annual prostate-specific antigen (PSA) testing could pick up cases of prostate cancer up to eight times as often in men with genetic hallmarks of Lynch syndrome than in those without.
Researchers found that many of the cancer cases in men with the syndrome were clinically significant, suggesting targeted screening has the potential to save lives.
The Institute of Cancer Research, London (ICR), scientists believe targeted annual screening from the age of 40 could lead to earlier diagnosis and treatment of prostate cancer in this high-risk group of men.
They also suggest that identifying patients who have Lynch syndrome could further guide their treatment.
This is because increasing evidence suggests that immunotherapies, which harness the immune system to attack cancer, may be particularly effective in men with these mutations if they have disease recurrence.
Ros Eeles, professor of oncogenetics at the ICR, consultant in clinical oncology and oncogenetics at The Royal Marsden NHS Foundation Trust, leads the Impact study.
She said: “Prostate cancer screening isn’t recommended for the general population, but we believe it could benefit some groups of men at high inherited risk.
“Our new findings show that PSA testing in men with Lynch syndrome is much more likely to pick up life-threatening prostate cancer than in the general population.
“We think that men with the gene faults causing Lynch syndrome are likely to benefit from regular PSA testing from the age of 40.
“Targeted screening has the potential to pick out aggressive prostate cancers at an early stage in men at high inherited risk, increasing their chances of survival.
“And because cancers in these men are more likely to be aggressive and potentially life-threatening, they would need to have radical treatment.
“I anticipate that these results, and evidence from our ongoing follow-up work, will influence future national and international screening guidelines for this group of men, with the aim of picking out prostate cancer earlier and potentially saving lives.”
The new research is part of the international Impact study which involves 828 men from families with Lynch syndrome at 34 centres in eight different countries.
It aims to assess whether regular PSA testing is an effective way to spot prostate cancer in men who carry certain genetic alterations that increase their risk.
More than 600 of the men in the study have faults in the MLH1, MSH2 or MSH6 genes which are associated with Lynch syndrome.
Researchers say PSA screening is not recommended for men in the general population because it has not been shown to be beneficial and there are concerns it can lead to over-diagnosis and over-treatment of cases.
But it could carry more promise for men who are at a high inherited risk, the study suggests.
Men in the new study were offered an annual PSA test, and those with a PSA deemed high were offered a biopsy to see if they had prostate cancer.
Researchers found annual PSA tests could effectively spot prostate cancer in men who inherited a mutation in the genes MSH2 or MSH6.
The study found that men with the MSH2 gene fault were eight times more likely to be diagnosed with prostate cancer than non-carriers, and were diagnosed at a younger age – an average of 58 years compared with 66.
Researchers say that crucially, men with the MSH2 gene fault more often had aggressive, potentially life-threatening tumours, with 85% showing clinically significant disease, compared with no non-carriers.
This suggests over diagnosis in MSH2 carriers is unlikely.
Meanwhile, MSH6 carriers were diagnosed at an average age of 62 years and 75% had life-threatening, or clinically significant, tumours.
Researchers are planning another five-year follow-up study.
Published in The Lancet Oncology the study was funded by Cancer Research UK, with additional support from the Ronald and Rita McAulay Foundation and the NIHR Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and the ICR.Internet Explorer Channel Network