The menopause, hormone replacement therapy and breast cancer

Concern exists that the reduction in breast cancer risk associated with the onset of the menopause will be negated with exposure to hormone replacement therapy (HRT). Evidence from large-scale randomised HRT trials support observational data that have shown a modest increase in breast cancer risk with long-term use (i.e. >15 years) of combined therapy, although this falls following HRT cessation suggesting a growth-promoting effect. Randomised evidence demonstrates that the efficacy of anti-estrogens, aromatase inhibitors and raloxifene in the treatment and chemoprevention of breast cancer are restricted to women with oestrogen receptor positive (ER +ve) disease; however, HRT has not been associated conclusively with a predominance of hormone sensitive breast cancer. Despite stimulating the breast cancer cell growth, HRT has not been shown to increase breast cancer recurrence or mortality when prescribed to breast cancer survivors experiencing oestrogen deficiency symptoms and randomised trials have been recommended and commenced. In conjunction with controlled breast cancer trials demonstrating a therapeutic benefit of high dose estrogens and interest in the use of additive oestrogen therapy in patients developing resistance to oestrogen deprivation, the dogma that HRT is an absolute contra-indication following diagnosis is challenged.