New data suggest that a combined oestrogen-proges-togen regime poses a greater risk of breast cancer in postmenopausal women than oestrogen alone (JAMA, 2000; 283: 485-91).
This finding comes from a study of more than 46,000 women across the US over 15 years to determine the risk of both regimes. The relative risk of developing breast cancer increases by 0.01 per cent for every year of oestrogen only therapy. However, the relative risk of developing breast cancer with the combination drug increased by 0.08 per cent every year.
The increased risk was most evident among thin women with a body mass index of 24.4 or less.
This study further demolishes the received wisdom among many doctors that combined HRT is the 'safer' variety.