The study, which combined the results of 26 international trials, showed 44 per cent of women with BRCA1 faults and 52 per cent of women with BRCA2 faults were alive five years after they were diagnosed with epithelial ovarian cancer.
This compares with 36 per cent of women without a fault in one of these genes who were alive five years after their diagnosis.
The researchers say having a faulty BRCA gene could alter the biology of a tumour, making it more responsive to treatment.
It could also be because the normal role of a BRCA gene is to repair damage to DNA. Having a faulty BRCA gene could leave the tumour less able to repair damaged DNA and so more vulnerable to chemotherapy.
Cancer Research UK’s Dr Paul Pharoah, lead author based at the University of Cambridge, said: “Our study is the largest on this topic to date, looking at just over 900 ovarian cancer patients with faulty BRCA1 genes and just over 300 with faulty BRCA2 genes.
“Our results could change the way ovarian cancer is treated. Women with BRCA faults respond better than we thought to current treatments but it’s important that researchers now look at what treatment approaches work best for women without those genetic faults.
“We also need to consider how our results affect research. Clinical trials should be designed to take this difference in survival into account. Otherwise trial results may not be an accurate reflection of what’s really going on.”
Around 6,800 women are diagnosed with ovarian cancer in the UK each year and up to 90 per cent of these cases are epithelial ovarian cancer. Around 10 per cent of women with epithelial ovarian cancer carry BRCA1 or BRCA2 faults.
Ovarian cancer is often diagnosed at a late stage and it is the fourth biggest cause of cancer death in women, with around 4,400 ovarian cancer deaths in the UK each year.
Dr Julie Sharp, senior science information manager at Cancer Research UK, said: “This is an intriguing study with important implications for the treatment of ovarian cancer. Women with faulty BRCA genes have up to a 40 per cent chance of developing ovarian cancer by the age of 70, but now we know that they are also more likely to survive the disease.
“Interestingly, this difference in survival isn’t seen in women with breast cancer who have faulty BRCA genes, so understanding why we’re seeing this in ovarian cancer could reveal some clues on how to improve treatment for the disease.”
For media enquiries please contact the Cancer Research UK press office on 020 3469 8300 or, out-of-hours, the duty press officer on 07050 264 059.
A multi-center study to evaluate the impact of germline BRCA1 and BRCA2 mutations on Ovarian Cancer Survival. Bolton et al. Journal of the American Medical Association.
Notes to editors
The vast majority of ovarian cancers are classified as “epithelial” and are believed to arise from the surface (epithelium) of the ovary.