BRCA gene does not affect survival in those treated for breast cancer

A new study has found that BRCA gene mutations do not affect the survival rates of breast cancer patients under 40, although women diagnosed with breast cancer under this age have a poorer outlook compared with those diagnosed at an older age.

Lead researcher Professor Diana Eccles at the University of Southampton, UK, said: 'No other study has followed a group of patients from diagnosis over a long period of time to discover if carrying a high-risk inherited BRCA gene alters the likelihood of being cured of breast cancer.' The study was published in The Lancet Oncology.

BRCA genes encode DNA repair molecules in human cells; however mutations in these genes have been linked to an increased risk of developing breast and ovarian cancers. Previous studies have suggested that between 45-90 percent of women with BRCA mutations develop breast cancer during their lifetime, compared with just 12.5 percent of the general UK population.

The study followed 2733 women from at 127 hospitals in the UK, all of whom had been diagnosed with breast cancer before the age of 40. Blood samples were used to identify those carrying BRCA1 or BRCA2 mutations (12 percent of participants). Researchers then tracked patient treatment for up to eight years. The majority of patients (89 percent) underwent chemotherapy, while 50 percent underwent mastectomies.

The study found that regardless of the BRCA mutations, survival rates at two, five and 10 years were very similar. Researchers state that this evidence could inform future treatment and help women and doctors make informed decisions regarding next steps. 

Dr Fiona MacNeill, consultant breast surgeon at The Royal Marsden NHS Foundation Trust said: 'This study can reassure young women with breast cancer, particularly those with triple negative cancer or who are BRCA carriers that breast conservation with radiotherapy is a safe option in the first decade after diagnosis and double mastectomy is not essential or mandatory at initial treatment. In view of this, younger women with breast cancer can take time to discuss whether radical breast surgery is the right choice for them as part of a longer-term risk reducing strategy.'

While this new evidence is encouraging for those with young-onset cancers, the majority of breast cancers (81 percent) appear in women over the age of 50. The researchers stated that their findings may not translate to older women carrying BRCA mutations and that further work would be necessary within this age range.

Professor Peter Fasching, from Friedrich-Alexander University Erlangen-Nuremberg, Germany, said in a commentary accompanying the study: 'This important topic needs more prospective research as preventive surgical measures might have an effect on what might be a very long life after a diagnosis of breast cancer at a young age.'