The effect of hormone replacement therapy on recall rate in the National Health Service Breast Screening Programme

Purpose: Hormone replacement therapy (HRT) can lead to an increase in the density of breast parenchyma on mammography and to the development of mammographically visible cysts and fibroadenomas. These changes may obscure features indicative of benign processes or mimic those of a carcinoma on screening mammography. This study was designed to assess the effect of HRT usage on the recall rate of women attending for routine breast screening. Method: Details of HRT usage were taken from 5699 consecutive women aged 49-64 attending for breast screening, Mammograms were read without knowledge of HRT usage and recall for assessment details collected. Results: A significant fall in recall rate was seen between the prevalent and incident screens in women not taking HRT (P < 0.016). This fall was not present in women taking HRT. The recall rate for the incident screen of women on HRT was 37% higher than that for women who did not take HRT; however the positive predive value for cancer of recall was lower at 3.7% compared to 12.9%. Conclusion: These results indicate that the recall rate for incident screening is likely to be higher in women on HRT. This increase in assessment will lead to increased cost and anxiety in the screened population.