Young women who carry the BRCA gene mutation and go on to be treated for breast cancer, have the same chances of survival as women without the mutation, the results of a new study suggest.

In the mid-1990s, it was discovered that mutations in the BRCA1 and BRCA2 genes significantly increased a woman's chance of developing breast and ovarian cancer.

It is now known that women who have a fault in either of these genes have a 45-90% increased risk of developing breast cancer compared with around 12% of women without these mutations.

UK researchers decided to investigate survival rates among those treated for the disease.

They looked at women who had been diagnosed between 2000 and 2008, when BRCA testing and risk-reducing surgery, such as a double mastectomy, were not as common. Now, women with early breast cancer and BRCA mutations are often offered risk-reducing surgery to help reduce future risk.

Over 2,700 women aged between 18 and 40, who had been treated in 127 UK hospitals, took part in the study. Almost 340 (12%) of these had BRCA 1 or 2 mutations.

Most of the participants (89%) underwent chemotherapy, 49% had breast conserving surgery, 50% had a mastectomy and less than 1% had no breast surgery.

The study found that there was no difference in overall survival rates between women with the gene mutations and those without. The results stood two, five and 10 years after the initial diagnosis. The findings were irrespective of whether the mutation was in the BRCA 1 or BRCA 2 gene, and body mass index and ethnicity did not affect the outcome.

"Our study is the largest of its kind, and our findings suggest that younger women with breast cancer who have a BRCA mutation have similar survival to women who do not carry the mutation after receiving treatment," explained Prof Diana Eccles of the University of Southampton and University Hospital Southampton.

She pointed out that women diagnosed with early breast cancer who carry a BRCA mutation are often offered double mastectomies soon after their diagnosis or chemotherapy treatment.

She said that women with a BRCA mutation who choose to delay additional surgery for one to two years to recover from their initial treatment should be reassured that this is unlikely to affect their long-term survival.

However, she emphasised that risk-reducing surgery is still likely to be beneficial for BRCA mutation carriers to prevent another new breast or ovarian cancer from developing in the future.

"Our findings suggest that this surgery does not have to be immediately undertaken along with the other treatment. In the longer term, risk-reducing surgery should be discussed as an option for BRCA1 mutation carriers in particular, to minimise their future risk of developing a new breast or ovarian cancer. Decisions about timing of additional surgery to reduce future cancer risks should take into account patient prognosis after their first cancer, and their personal preferences," Prof Eccles added.

The researchers acknowledged that their results may not translate to older women with BRCA mutations.

Details of these findings are published in the journal, The Lancet Oncology.

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