MANY Australian women are failing to protect themselves from breast and ovarian cancer despite knowing they carry a dangerous gene mutation, according to a new study.
About 20 per cent are likely to have their breasts removed, according to the study which tracked 325 women with BRCA1 or BRCA2 mutations for up to 15 years.
The study, published in the Medical Journal of Australia, shows about 40 per cent have their ovaries and fallopian tubes removed.
Apart from protecting against ovarian cancer, this procedure reduced the risk of breast cancer if done before menopause, said research leader Professor Kelly-Anne Phillips from the Peter MacCallum Cancer Centre in Melbourne.
Three per cent of the women in the study participated in a clinical trial of Tamoxifen, a medication which Prof Phillips and her team recently showed helped halve the risk of breast cancer.
The next phase of the research would involve face-to-face interviews with women and their doctors to understand why some women did not use cancer prevention strategies.
"All the options have advantages and disadvantages. These are complex and personal decisions," said Prof Phillips.
Data collection for the study ended in May 2012, before actor Angelina Jolie went public about her double mastectomy.
An increase in genetic testing has been reported in Australia since then and Prof Phillips told AAP it was possible this had prompted more women to take preventative action.
But prevention during the research period was low compared with other countries, she said.
One reason could be that women were not aware of the latest options.
"The evidence for the different interventions has changed significantly over the past few years," she said.
"My advice is for women who know they have the gene mutation to talk to their specialist at regular intervals.
"Women who don't know if they have the mutation but are concerned about their family history should talk to their GP.
BRCA1 mutation carriers have a 65 per cent chance of developing breast cancer and a 39 per cent chance of ovarian cancer by the age of 70, according to the study.
BRCA2 mutation carriers have a 45 per cent chance of breast cancer and 11 per cent risk of ovarian cancer.
"There are things women can do that will dramatically reduce their risk," said Prof Phillips.