Genetic defects which increase the risk of breast and ovarian cancers in women have now been found to increase the risk of men developing prostate cancer.

The new findings mean that men with a strong family history of ‘female’ cancers could be tested for genetic defects and regularly screened for signs of prostate tumours. 

It was in the mid-1990s that scientists identified that faulty versions of the BRCA1 and BRCA2 genes increased the risk of breast and ovarian cancers in women. They are thought to be responsible for around one in 10 breast cancer cases. 

Hollywood actress Angelina Jolie underwent a double mastectomy (breast removal) in 2013 and had her ovaries and fallopian tubes removed the following year after being told she had inherited the BRCA1 gene. 

Down the years, numerous studies have also hinted the same mutations, which affect around one in 300 people, may contribute to a wide range of other types of cancer – including prostate. But many of these studies were small and inconclusive. 

The latest investigation, published in January in the Journal of Clinical Oncology, provides the strongest evidence yet that they are a factor – doubling a man’s chances of prostate cancer forming. 

The research was undertaken by a team of experts at the University of Cambridge in the UK, who tracked 3,200 families who have one or more members carrying the BRCA1 mutation and another 2,200 families affected by BRCA2. 

Their results revealed men with a BRCA2 mutation had a 27 per cent chance of prostate cancer by the time they reach 80 – more than double the rate of men not carrying the faulty gene.

BRCA1 defects, on the other hand, did not seem to have any damaging effect. 

Other tumours were also implicated – the chance of pancreatic cancer in men with a defective copy of either BRCA1 or BRCA2 was found to double. 

Stomach cancer cases were also higher, although the data on this was less robust, while malignant melanoma – the most dangerous form of skin cancer – was not influenced by the gene profile. 

The results raise the possibility that men whose families have been devastated by cancer could be tested to see if they carry the rogue gene and screened regularly for prostate tumours with a PSA test – a blood test that measures markers associated with the formation of cancer. 

PSA testing is far from perfect – a high score may be due to other prostate issues rather than cancer – but could still be a useful way of monitoring those most at risk, experts say. 

Cancer Research UK, which funded the latest study, said GPs and family doctors can refer patients to a genetics clinic for further testing. Cancer Research UK’s chief executive, Michelle Mitchell, said the breakthrough had given doctors ‘important new insights’ into BRCA gene mutations and prostate cancer. She added: ‘Cancers caused by inherited faulty BRCA genes are relatively rare, and other factors like age, smoking, diet and other preventable factors contribute to a person’s risk. But improving our understanding of how faults in our genes are associated with certain cancers puts us in a much better position to pinpoint those at a higher risk.’ 

SOURCE: Cancer Risks Associated With BRCA1 and BRCA2 Pathogenic Variants. Journal of Clinical Oncology, 2022