A major re-analysis of the worldwide evidence linking breast cancer with HRT has concluded that the risk of the disease increased in women using HRT and that the longer the use, the greater the increase.
Researchers found that the average length of time a woman takes HRT is 11 years, and that the risk of breast cancer increases by 2.3 per cent for every year she uses HRT. The risk was also greatly increased in women with a lower than average body weight.
The analysis showed that those who developed cancer while on HRT tended to develop more localized tumours rather than one which had spread to other parts of the body. But the researchers acknowledged that this was not necessarily a protective effect of HRT but was probably due to the emphasis on regular breast examinations and thus earlier detection in those on the drug.
The good news is that the effect reduces on stopping HRT and disappears after about five years (Lancet, 1997; 350: 1047-59).
For more information see WDDTY Guide to Menopause and vol 7 no 10.