abstract: Screening Mammography Use among Current, Former, and Never Hormone Therapy Users May Not Explain Recent Declines in Breast Cancer Incidence

Conclusions:
Differential screening mammography rates by HT use do not explain invasive breast cancer incidence declines. Our data suggest discontinuing HT has an immediate effect on breast cancer rates, lending support to the mechanism that cessation leads to tumor regression.

Impact:
Studies examining the influence of a changing exposure in relation to outcomes should account for varying exposures, individuals' characteristics, as well as screening methods and frequency.