Screening mammography: sensitivity and specificity in relation to hormone replacement therapy.

PURPOSE: To evaluate the possible effects of hormone replacement therapy (HRT) on the sensitivity and specificity of screening mammography. MATERIALS AND METHODS: Twenty thousand women aged 50 years or older were interviewed about use of HRT during the second round of screening mammography; of these, 3,126 were currently using, 2,158 had previously used, and 14,716 had never used HRT. Women with breasts known to be composed of predominantly fatty tissue were examined with one-view mammography; otherwise, two-view mammography was used. RESULTS: The sensitivity of screening mammography was 96% (95% confidence interval, 81.0%, 99.1%) in women currently using, 92% (61.5%, 99.8%) in women who had previously used, and 91% (85.7%, 96.8%) in women who had never used HRT. The specificity was 94% (93.3%, 95.0%), 95% (93.7%, 95.6%), and 95% (94.8%, 95.5%), respectively. There was a slight decrease in specificity with duration of treatment for the current-user group. However, specificity in women treated with continuous combined estradiol-progestin for less than 3 years (90%) was lower than that in women treated with other regimens (95%, P = .037). CONCLUSION: There was no decrease in the sensitivity of screening mammography in women currently using HRT, but there was a marginal decrease in specificity varying with the HRT regimen and duration of treatment.