In Postmenopausal Women, Long-Term Estrogen Tied to Breast Cancer Risk

Postmenopausal women who take estrogen therapy for long periods of time may have a significantly increased risk of breast cancer, a new study suggested.

These findings further demonstrate the potential role of postmenopausal estrogen therapy in elevated breast cancer risk, which is likely due to estrogen’s promotive role in breast cancer.

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“We suggest that a woman's breast cancer risks be seriously considered when she is prescribed long-term estrogen,” the authors of the study wrote.

The authors arrived at their conclusion following a cohort study of 454 female members of a large health maintenance organization located in northern California.

Among women who had taken estrogen for at least 5 years (n = 232), the average duration of use was 17.2 years compared with non-users (n = 222).

Ultimately, the results of the study indicated that 26 (11.2%) estrogen users had developed breast cancer compared with 9 (4.1%) non-users by the end of 1995 (relative risk [RR] 2.8).

However, the RR for estrogen decreased to 2.0 following adjustment for age and multiple breast cancer risk factors, including breast cancer surveillance.

—Christina Vogt

Reference:

Ettinger B, Quesenberry C, Schroeder DA, Friedman G. Long-term postmenopausal estrogen therapy may be associated with increased risk of breast cancer: a cohort study. Menopause. 2018;25(11):1191-1194. doi:10.1097/GME.0000000000001216.