Hormone replacement therapy in women with previous breast cancer

As breast cancer is known to be a tumour sensitive to the effects of endogenous oestrogens, clinicians are reluctant to prescribe hormone replacement therapy (HRT) to women with a history of previous breast cancer for fear of stimulating disease recurrence, and it is currently contraindicated in this group of women. However an increasing proportion of breast cancer patients are requesting the use of HRT to relieve the symptoms of oestrogen deficiency, which are also a common side-effect of adjuvant therapy for breast cancer Observational data on the use of HRT in breast cancer survivors has not demonstrated an increase in disease recurrence, but uncertainty will continue in the absence of data from prospective, randomized trials. This review aims to demonstrate why it is ethical and scientifically important to undertake such studies.