This study shows that, based on a recent meta-analysis of over 50 epidemiological studies published on the risk of breast cancer with hormone replacement therapy, current users of HRT, or those who ceased one to four years previously, had a small increased relative risk of breast cancer. The combined analysis reported no increased risk for HRT users of less than five years. For women who had used HRT for five years or longer, the average relative risk of breast cancer increased by approximately two percent per year of use. This reported relative risk for breast cancer with HRT would account for an excess of two, six or 12 cases per 1,000 HRT users after five, ten or 15 years of use, respectively. Within five years of discontinuation of HRT use, the increased relative risk virtually disappeared.
Age is also a risk factor.
It is therefore important to note that the increased risk as reported is therefore extremely small, particularly when compared with other known risk factors. Canadian women who have reached menopause are at a greater risk of developing other diseases, such as cardiovascular disease, if they don't take hormone replacement therapy. Heart disease is the number one killer of women in this age group. Because the subjects were surveyed over the past 20 years, they could have been on higher doses and different regimens of estrogen-progestin than are commonly prescribed today. The results, therefore, may not be reflective of current lower-dose therapies.