Bisphosphonates 'reduce breast cancer risk by a third'

15 Dec 09

Oral bisphosphonates prescribed to women with osteoporosis or who are at risk of a bone fracture reduced the number of invasive breast cancers by 32%, a large study found.

An analysis of data collected as part of the Women’s Health Initiative found that in the cohort of 10,000 women who had their bone mineral density analysed, there were 32% fewer cases of breast cancer in women who used bisphosphonates – mostly alendronate – compared to women who did not use the drugs.

The researchers from the University of California at Los Angeles also there were 30% fewer oestrogen-receptor positive cancers and 34% fewer entry-receptor negative cancers among bisphosphonate users, although the this was not statistically significant.

Lead researcher Dr Rowan Chlebowski, a medical oncologist at University of California, Los Angeles, presented the study at the San Antonia Breast Cancer Symposium in Texas this week.

Dr Chlebowski said oral bisphosphonates ‘appeared to make bone less hospitable to breast cancer.’

He added: ‘The idea that bisphosphonates could reduce breast cancer incidence is very exciting because there are millions of prescriptions for these agents written annually targeting bone health, and more could easily be used to counteract both osteoporosis and breast cancer.’

San Antonio Breast Cancer Symposium, Texas, 9 - 13 December 2009, abstract number 21