Results and Signals from the Ongoing NCI Multi-Generational DES Follow-up Study

Linda Titus, PhD, Dartmouth Geisel School of Medicine, NH, USA Presented at BeyondGenes.org conference, December 4, 2020 This presentation will provide an overview of the US National Cancer Institute (NCI) DES Combined Cohort Follow-up Study. Strengths of the NCI study include its relatively large size, medical record documentation of DES exposure or lack of exposure, and the extended follow-up of three generations of DES exposed and unexposed individuals. The "first generation" of individuals in the NCI study comprises women who were given DES during pregnancy and those who were not given DES; the "second generation" comprises the sons and daughters of the first generation women; i.e., men and women who were prenatally DES exposed or unexposed; the "third generation," sometimes referred to as the "granddaughters" generation, comprises the daughters of second generation women who were prenatally DES exposed or unexposed. The presentation will focus on the findings from the NCI Third Generation Study -- women whose mothers were or were not prenatally exposed to DES. Findings to date for the third generation DES exposed women, compared to the unexposed, suggest an increased likelihood of menstrual irregularities and a possible excess of ovarian cancer based, however, on only 3 cases. Further work is underway to assess these outcomes, as well as the possibility of adverse reproductive outcomes, which affected their prenatally exposed mothers.