Relationship between the type of hormone replacement

ABSTRACT

Objective@#After Women's Health Initiative (WHI) trial, hormone replacement therapy (HRT) prescription rate dropped by 16% in Korea. We investigated the relationship between the type of HRT and incidence of breast cancer (BC) in postmenopausal women in Korea.Material & Methods: We compared the prevalence of BC in 356,160 women on HRT, who reached menopause between 2004 and 2007. We divided the type and duration of HRT into three categories, i.e., estrogen-progestogen therapy (EPT), estrogen-only therapy (ET), tibolone, and 1– 3 years, 3–5 years, and ＞5 years, respectively. @*Results@#Regarding the type of HRT among all age groups, BC risk (BCR) was lower in the tibolone group (P＜0.01). Based on age group, BCR was lower in the 50–59 years group using EPT (P=0.03) and tibolone (P＜0.01). HRT administration for ＜3 years showed a significant decrease in the tibolone group (P=0.04) and an increase in the ET group (P=0.03). In groups undergoing HRT for ＞5 years, BCR in all groups decreased (P＜0.05). @*Conclusions@#The results suggest that tibolone reduces the risk of BC in women aged ≥50 years and HRT use for ≥5 years was related to significantly decreased BCR in Korea.