New role for Tamoxifen in saving high-risk patients

August 7th, 2013

A multinational research study led by researchers at the University of Melbourne and Melbourne’s Peter MacCallum Cancer Centre has revealed that those women with a strong genetic predisposition to breast cancer who take the cancer prevention tablet, tamoxifen, after their first tumour have a dramatically reduced risk of developing a new breast cancer.

The global study was led by Medical Oncologist and Professorial Fellow at the University of Melbourne, Professor Kelly-Anne Phillips, and published in the Journal of Clinical Oncology. Professor Phillips is also a National Breast Cancer Foundation Practitioner Fellow and this research was supported by funding from NBCF and Cancer Australia.

The study involved about 2,500 women from Europe, North America and Australia who have inherited mutations in BRCA1 or BRCA2, the breast cancer susceptibility genes, and who had been diagnosed with breast cancer. These women were placed on Tamoxifen.

Tamoxifen blocks the action of oestrogen. It has been used for decades to treat breast cancer and has recently been shown to prevent breast cancers in many women. The use of tamoxifen to prevent breast cancer is now endorsed by Australian, American and UK clinical guidelines.

Until now, however, there has been limited information about whether tamoxifen reduces breast cancer risk for women who are at the very highest level of risk, those who carry a mutation in BRCA1 or BRCA2. This study, the largest to date, suggests that it could work for these high-risk women by halving their breast cancer risk.

Lead author, Professor Kelly-Anne Phillips says “In the past, the only way of reducing breast cancer risk for these high-risk women was to do invasive surgery to remove their breasts and/or ovaries. For women who choose not to undergo such surgery, or who would prefer to delay surgery until they are older, tamoxifen could now be a viable alternative.”

Such was the case for US actress Angelina Jolie who was found to carry one of these genes. Previous research led by Professor Phillips revealed that only 1 in 5 Australian women with a mutation in BRCA1 or BRCA2 choose to undergo bilateral mastectomy to prevent cancer. Professor Phillips says the possible use of tamoxifen should now be discussed with women who are at high risk for breast cancer but who choose not to have their breasts removed.

Professor John Hopper, lead researcher from the School of Population and Global Health at the University of Melbourne, says it is well-documented that tamoxifen is effective in reducing the risk of breast cancer for an unaffected woman who has a family history of the disease.

“Our study shows that this benefit is likely to extend to a woman who has a high genetic predisposition to breast cancer because she carries a mutation in BRCA1 or BRCA2.”

“In light of our findings, it is clear that women who have a mutation in BRCA1 or BRCA2 should review their management plan with their specialist and re-discuss the options available to them to lower that risk.”

This important finding has come from more than 20 years of research involving breast cancer families recruited from cancer registries and clinics across the country.

“Without the generous contributions of those families we would not be able to make such discoveries which help future generations fight breast cancer,” he says.