Diethylstilbestrol Exposure — 1984

IN this issue of the Journal, Greenberg et al.1 report a collaborative study, involving approximately 6000 women, in which a small but significant increase in the risk of breast cancer was observed in those exposed to diethylstilbestrol (DES) during pregnancy. The increased risk did not appear until 20 years or more after exposure and became higher in older subjects. Greenberg et al. evaluated the potential of a confounding bias on their results, and none was noted. They are appropriately cautious in the interpretation of these new findings. As noted in the article, the results differ from those of three . . .