Hormone Replacement Therapy and Breast Cancer

• Published in: Journal of Japan Association of Breast Cancer Screening Vol. 7; no. 3; pp. 237 - 246
• Main Author: Dobashi, Kazuyoshi
• Format: Journal Article
• Language: Japanese
• Published: Japan Association of Breast Cancer Screening 1998
• Subjects: breast cancer; hormone replacement therapy
• ISSN: 0918-0729; 1882-6873
• DOI: 10.3804/jjabcs.7.237

Evaluation of the role of estrogen and progesterone in hormone replacement therapy (HRT) as a cause and promoter of breast cancer should begin with a study of the effect of these hormones on normal breast tissue. Cyclic alterations in the histologic changes of the breast in relation to menstruation have been confirmed in some studies. However, the histological influence on the breast of exogenous estrogen and progestin in postmenopausal women remains a very controversial subject, and there has been little consistency regarding the relative risk of HRT and breast cancer across many epidemiological studies. However, the Collaborative Group on Hormonal Factors in Breast Cancer has brought together and reanalysed about 90% of the worldwide epidemiological evidence on the relationship between breast cancer risk and the use of HRT. These analyses have revealed that the risk of breast cancer in HRT users is significantly increased. However, whether HRT affects mortality from breast cancer is not known.