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November 1969

Synthetic Estrogen-Progestin Combinations: Effect on Hormone-sensitive Breast Cancer in the Rat

Author Affiliations

Portland, Ore
From the Department of Surgery, University of Oregon Medical School, Portland. Dr. McSweeney is now at the University of Vermont College of Medicine, Burlington.

Arch Surg. 1969;99(5):652-654. doi:10.1001/archsurg.1969.01340170104025

Recently Huggins et al1 described a hormone-sensitive breast carcinoma in the Sprague-Dawley rat induced by one feeding of the carcinogen—7,12-dimethylbenz- [α]anthracene (DMBA). Using this induced tumor it has been shown in this laboratory that it is possible to extinguish hormone-sensitive tumors in the rat with 10μc of diethylstilbestrol diphosphate tagged with radioactive phosphorous (32P). The tumor uptake of 32P is doubled by its incorporation into the diethylstilbestrol molecule.2 The dramatic response of these tumors to diethylstilbestrol and 32P-tagged diethylstilbestrol diphosphate, as well as the fact that Huggins has reported similar tumors to be extinguished by a mixture of estradiol 17-β and progesterone,3 led us to study the effect of various other commonly used synthetic female hormones. The following substances were tested: (1) the synthetic progestin-estrogen combination of norethynodrel with mestranol (Enovid), (2) the synthetic progestin, norethynodrel, and (3) the synthetic estrogen, diethylstilbestrol. The chemical