Hormone replacement therapy (HRT) and its effect on mammographic specificity and sensitivity

It is now widely recognised that the use of hormone replacement therapy (HRT) can influence mammographic pattern. Approximately 17–24% of women using HRT may have demonstrable changes on sequential mammography consisting either of a generalised increase in background density or focal changes such as cyst formation or an increase in the size of fibroadenomata. In addition to demonstrable change, HRT may also lead to maintenance of breast density, so that the natural involution usually seen with age is not visualised. As the number of women taking HRT increases, and these women are in the age group targeted by breast screening programmes, there has been an increasing interest in the influence of HRT on the sensitivity and specificity of mammography.

Over the past few years several studies have been published addressing this issue and the results of these will be reviewed within the lecture. Overall, there is evidence of a reduction in sensitivity with HRT use, although this may be confined to women with a dense background pattern only. In addition, there is also evidence of decreased specificity in women taking HRT.