Hormone replacement therapy for the primary prevention of chronic diseases: recommendation statement from the Canadian Task Force on Preventive Health Care

The US Preventive Services Task Force,15 the American College of Obstetricians and Gynecologists,16 the North American Menopause Society (NAMS),17 Health Canada,18 the US Food and Drug Administration (FDA)19 and, in a joint statement, the Heart and Stroke Foundation of Canada, the Society of Obstetricians and Gynaecologists of Canada and the Canadian Cardiovascular Society20 all have recommended that asymptomatic women should not use combination estrogen-progestin therapy for the prevention of cardiovascular disease or other chronic diseases, because the risks outweigh the benefits. They advocate that women considering HRT should discuss their individual risks with their physician. These groups also recommend that women who choose to take HRT to relieve menopausal symptoms should use as low a dose as possible and for as short a time as possible, with periodic re-evaluation of whether HRT is still required. The FDA and NAMS have extended these recommendations to include all estrogen preparations, including unopposed estrogen. Their stance is that, until there is evidence from randomized controlled trials showing benefit, other methods of lowering cardiovascular disease and cancer risk (e.g., smoking cessation, and lifestyle and diet changes) should be used. * Long-term current use of HRT with unopposed estrogen or combination therapy is associated with an increased risk of breast cancer. This risk increases with duration of use.12 The WHI estrogen-plus-progestin results indicated an HR of 1.26 (adjusted 95% CI 1.00-1.59), or an additional 8 cases of invasive breast cancer per 10 000 person-years of HRT use (38 v. 30 events per 10 000 person-years) after 5.2 years.13 The Million Women Study recently showed that, compared with women who never used HRT, those who were using HRT were 1.66 times more likely to develop breast cancer and 1.22 times more likely to die of it.25 Recent data suggest that combination therapy with progestin may confer a higher risk than unopposed estrogen.13,25-27 * Before the publication of the WHI estrogen-progestin trial results, it was estimated that 22% of Canadian women aged 45-64 were currently using HRT, with highest use (33%) among those 50-54 years of age.42 Although many women have been taking combination HRT for the prevention of chronic diseases, the current evidence indicates that the harms outweigh the benefits, demonstrating an increased risk of breast cancer, venous thromboembolism, pulmonary embolism, stroke, myocardia