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HRT and risk of breast cancer death

 

Clinical bottom line

The available evidence is that use of HRT is not associated with an increased risk of breast cancer.


Reference

K Nanda et al. Hormone replacement therapy and the risk of death from breast cancer: a meta-analysis. American Journal of Obstetrics and Gynecology 2002 186: 325-334.

Study

This was a systematic review using several electronic databases, reference reviews, and contacts with experts and HRT-manufacturing companies for any studies relating to use of hormone replacement therapy (HRT) and death from breast cancer, without any language restriction. Included studies had to be original research on humans, with HRT use as exposure and death from breast cancer as the outcome. The study had to compare the risk of fatal breast cancer among healthy users with that of nonusers.

Results

Ten studies were found, ranging from over 1,000 breast cancer deaths to four, and mostly published in the late 1980s through the 1990s. The overall risk was not different for users and nonusers , with a relative risk ranging from 0.48 to 1.89. Most studies showed a reduced risk, but not significantly so (Figure 1).

Figure 1: Relative risk of breast cancer death in users of HRT. Ever use in all except Grodstein, in which it was current use. Numbers in parenthesis show the number of breast cancer deaths in each study


Comment

These were all observational studies, and while they all made various adjustment for known or expected confounding factors, some potential for bias may still exist. The bottom line for now is that there would seem to be no increased risk of a woman dying with breast cancer after having used HRT.