In a new study, researchers from Cancer Research Insitiute, UK suggests that women on tamoxifen have a reduced breast cancer risk compared to those on placebo. They report on a large scale trial of tamoxifen to prevent breast cancer. A group of 6050 women aged 36 to 65 years, from the UK, Australia, New Zealand and Europe took either tamoxifen or placebo for five years. All the women were considered as being at increased risk of breast cancer, because they had either a family history of the disease or they had a breast lesion linked to increased risk.
The researchers found that the tamoxifen group had a one third reduction in breast cancer risk. But they had an increased risk of endometrial cancer - 10 cases in this group compared to five in the placebo group. These numbers are small, but tamoxifen use was also linked to increased frequency of blood clotting problems, especially after surgery. The results suggest that tamoxifen use really should be considered in the context of the risk versus benefit balance for the individual woman.