Why mammography sometimes misses the mark

The sensitivity and specificity of screening mammography is lower in women taking hormone replacement therapy (HRT), those who have had breast surgery, and those who are thin, according to results from a sample of women from the Million Women Study.

Researchers calculated the overall sensitivity and specificity of screening mammography to be 86.6% and 96.8%, respectively. For current, past, and never users of HRT, sensitivity was calculated to be 83%, 84.7%, and 92.1%, respectively. Specificity was 96.8%, 97.8%, and 98.1%, respectively.

For women with previous breast surgery, sensitivity was 83.5%, compared to 89.4% for those who had not gone under the knife, and specificity was 96.2% versus 97.4%, respectively. As for women with a body mass index less than 25 versus women with a BMI of 25 or more, sensitivity was 85.7% versus 91% and specificity was 97.2% versus 97.4%, respectively.