Hormone replacement therapy increases risk of breast cancer

摘要

The risk of breast cancer increases slightly in women using hormone replacement therapy (HRT), and this risk increases the longer the treatment is used, according to a thorough reanalysis of data on more than 160 000 women. Many individual studies of the effects of HRT on the risk of breast cancer have been published, but because results differ it has not been dear until now how great the increased risk might be and even if a risk existed at all.