PREVENTIVE surgery can drastically reduce the risk of breast and ovarian cancer in women with an inherited predisposition to breast cancer, according to an international study.(1)

No breast cancers were diagnosed in 247 women who underwent risk-reducing mastectomy during 3 years of follow-up, in a  European, US and Canadian study of 2482 women with BRCA1 or BRCA2 gene mutations identified between 1974 and 2008.

In contrast, 7% of 1372 women who did not have the surgery were diagnosed with the disease over a similar follow-up period.

Currently only 17% of Australian women who tested positive for the BRCA1 or BRCA2 mutation had a risk-reducing mastectomy within 6 years, according to Associate Professor Kelly-Anne Phillips, medical oncologist at the Peter MacCallum Cancer Centre in Melbourne.

However, 50% of Australian women who tested positive for the mutations had a prophylactic salpingo-oophorectomy. Of those who were over 40 years of age, 72% had the operation within 6 years, once they were past their childbearing years, she said.

Prophylactic salpingo-oophorectomy was also shown to be beneficial in the international study.

It was associated with a significant decrease in ovarian cancer risk in BRCA1/2 mutation carriers, and in those with and without a prior diagnosis of breast cancer.

There was also a significant reduction in breast cancer risk following salpingo-oophorectomy in women with mutations in either gene without a prior cancer diagnosis.

The surgery was associated with a lower risk of all-cause mortality, breast cancer mortality and ovarian cancer mortality.

Leading breast surgeon Professor Christobel Saunders, of the QEII Medical Centre in Perth, said the study provided valuable new information for BRCA1/2 mutation carriers.

“Risk-reducing mastectomy does just about wipe out risk of developing breast cancer in women who have not yet developed the disease, and risk-reducing salpingo-oophorectomy decreases this risk,” she said.

Another important finding was how timing affected the success of salpingo-oophorectomy, she said, with the surgery most likely to be beneficial before 50 years of age.

Dr Helen Zorbas, CEO of the National Breast and Ovarian Cancer Centre, said women with BRCA1/2 mutations should be referred to a family cancer clinic for further assessment and development of an individual management plan.

“This may include advice around surveillance and risk reduction, including risk-reducing surgery,” she said.

About 5% of breast cancers and 10% of ovarian cancers involve an inherited gene fault.

JAMA 2010; 304: 967-975.

 

Posted 6 September 2010

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