First Major Study Supports Screening in Men at Higher Genetic Risk of Prostate Cancer
10 September 2010 - Men at higher risk of prostate cancer due to genetic changes may benefit from regular screening, research by ICR scientists has found.
Mutations in the BRCA1 and BRCA2 genes are not common in the population but are known to significantly increase prostate cancer risk for carriers.
IMPACT is the first multinational study looking whether screening men with these known prostate cancer predisposition genes would lead to earlier diagnosis. The study will ultimately screen 1,700 men for at least five years, but a preliminary analysis has been done for the first 300 men enrolled in the study.
The men – 205 with confirmed BRCA1 or BRCA2 mutations and 95 who had tested negative for the mutations - were all offered annual prostate specific antigen (PSA) blood testing. The 24 men who had an elevated PSA were given a follow-up biopsy. The biopsies revealed that a higher proportion of mutation carriers had prostate cancer than non-carriers: nine, representing a 3.9 per cent diagnosis rate, compared with two, a 2.1 per cent diagnosis rate.
The predictive value of the test – the number of cancers detected relative to the number of biopsies conducted – was 48 per cent, whereas such tests in the general population have a lower value of 24 per cent.
There are concerns that a nationwide screening programme using PSA testing may lead to overdiagnosis and treatment of men with low-risk disease who would not otherwise need therapy. But in this study, 78 per cent of mutation carriers had intermediate or high-risk disease which needed treatment, compared with the 35 per cent found for a population-wide study.
“This adds to the increasing evidence that BRCA mutation carriers develop more aggressive disease,” Chief Investigator Professor Ros Eeles says. “This study provides support for continued screening in men with genetic mutations.”