An observational study from Canada has shown that a decline in the use of HRT over the past decade was followed by a reduction in the incidence of breast cancer. Data on HRT prescriptions dispensed for women aged 50-69, during the years 2001-2006, was collated from a national registry. Information about current HRT use was obtained by telephone from a sample of 1,200 women in this age group already enrolled in the National Population Health Survey. However, the data are observations of association only, and are not controlled for other risk factors for breast cancer such as parity and alcohol intake. The absolute risk of breast cancer to an individual user of HRT is small (and smaller still in oestrogen-only formulation users). The potential benefits need to be weighed up against the risks for each individual patient. [With external links to current evidence and summaries]