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April 24, 1987

Estrogens and Risk of Breast Cancer

Author Affiliations

University of Nebraska Medical Center Omaha

University of Nebraska Medical Center Omaha

JAMA. 1987;257(16):2165-2166. doi:10.1001/jama.1987.03390160051017

To the Editor.—  We wish to urge caution in accepting the conclusion of Wingo et al1 that estrogen replacement therapy does not increase the risk of breast cancer in postmenopausal women. Only 114 of the 942 cancer cases and 154 of 1117 controls had used estrogen for over ten years. Only 48 (2%) of the 2059 women had stopped using estrogen more than ten years ago. We question whether this duration of follow-up during and after estrogen therapy is long enough to justify their conclusion. The latent period between initial estrogen exposure and the appearance of breast cancer is at least 15 years for nulliparous women, as deduced from the interval between onset of menses and the initial rise in breast cancer incidence in countries throughout the world.2 In pregnant women, large doses of diethylstilbestrol did not induce a significant increase in breast cancer incidence until more than