Relationship Between Long Durations and Different Regimens of Hormone Therapy and Risk of Breast Cancer

Top Cited Papers
Open Access
Abstract
There is considerable evidence from observational studies,1 and now from a randomized controlled trial, the Women's Health Initiative (WHI),2 that use of combined estrogen and progestin hormone replacement therapy (CHRT) is associated with an increased risk of breast cancer. Specifically, a pooled analysis of 51 observational studies found that current users of CHRT or progestin alone for 5 years or longer had a 53% increase in risk of breast cancer,1 and after 5.2 years of follow-up the WHI reported that CHRT was associated with a statistically nonsignificant 26% increase in breast cancer risk.2