Postmenopausal hormone therapy and risk of breast cancer.

Risks from hormone use among postmenopausal women will be particularly important in the future, given the worldwide increase in the number of older women in the population. Recent randomized clinical trials and epidemiological studies have reported various opinions on the association between the risk of breast cancer and postmenopausal hormone therapy (HT), especially the differences between therapy with unopposed estrogen and combined estrogen-progestin. The currently available data do not provide sufficient evidence to prove a causal association between postmenopausal HT and breast cancer. However, a possible risk of breast cancer associated with long-term HT usage should not be ignored, given that the degree of association between breast cancer and postmenopausal HT remains controversial. Unanswered questions include whether HT has a positive impact on breast cancer, and whether different types and routes of estrogen and progestogens, as well as the duration and cessation of HT use have different impacts on this disorder. Despite this, HT is still the most effective method of relieving climacteric symptoms for many postmenopausal women. Since the effect of HT on breast cancer risk may be related to individual susceptibility, we recommend close follow-up through mammography and/or breast sonography and an even more detailed evaluation of the potential of exogenous hormones inducing epithelial hyperplasia in those with increased breast density or any other high risk factors.