Estrogen/hormone replacement therapy and the etiology of breast cancer

ERT/HRT is clearly of use in relieving menopausal symptoms such as hot flashes and genitourinary changes. ERT/HRT also clearly reduces the risks of osteoporotic fracture, of cardiovascular events and deaths, and of developing colon cancer. ERT and, perhaps even more, HRT are, however, associated with an increased risk of developing breast cancer. This effect becomes more marked with long-term use (> or = 10 years); ERT/HRT use for more than 10 years is also associated with an increase in deaths from breast cancer. Because the underlying mortality risk for the average woman is, however, much greater from cardiovascular disease (approximately 22%) than from breast cancer (approximately 3.3%), the reduction in risk of cardiovascular death associated with ERT/HRT (from 22% to 15%) much outweighs the increase in risk of death from breast cancer (from 3.3% to 4.1%). Thus, overall, the average woman will gain more year(s) of life than she will lose by taking ERT/HRT. Even for a woman with a high risk of breast cancer and a low risk of cardiovascular disease, there will still be a net, although lower, gain in year(s) of life. Thus, the use of ERT/HRT would seem well worth considering for a well woman at the time of menopause.