Abstract LB-26: Biomarker changes in the endometrium of morbidly obese women undergoing bariatric surgery: Implications for endometrial cancer risk reduction.

Introduction: With increasing obesity rates in the US and around the world, both endometrial cancer morbidity and mortality are on the rise. The objectives of this study were to observe changes occurring in several biomarkers in the endometrium of asymptomatic morbidly obese women pre and post bariatric surgery, with the hypothesis that some of the premalignant changes may be normalized with weight loss. Methods: Endometrial samples were obtained from obese women at the time of roux en y gastric bypass bariatric surgery and one year following the surgery. Both investigators and pathologists were blinded to the status of patients until the conclusion of the study. All endometrial biopsies were subjected to immunohistochemical stains for hormone receptors, Estrogen (ER), Progesterone (PR) and Androgen (AR) along with stains for CD3, CD20, COX 2,and Ki-67 using standard immunohistochemistry protocols. Hormone receptor status was expressed using H score. Paired T-tests and non-parametric Wilcoxon signed-rank test was performed to compare the changes for ER, PR, and AR expression before and after the surgery. The exact McNemar/Bowker tests of symmetry were performed to compare proportions between categories for matched pairs (pre and post treatment) for CD3, CD20, COX2, and Ki-67. In addition, Chi Squire goodness-of-fit test has been used to test equality of distribution between categories by sub groups at the baseline. Results: 59 women were enrolled and underwent an initial biopsy. The mean (range) age was 42 year (22-62) and the mean (range) weight and BMI prior to surgery was 127 kg (87-176) and 46.8 kg/m2 (36-64.3) respectively. Abnormal endometrial findings (three simple and one complex hyperplasia, all without atypia) were seen in 6.8% of patients presenting for bariatric surgery (4/59)). The sign-rank test demonstrated marginally significant difference (p-value=0.0522) in H score for ER. Statistically significant difference has been observed between matched pre and post surgery levels of CD20 based on exact McNemar test (p-value=0.0196). Since sample size was too small, McNemar-Bowker test didn9t demonstrate significance for CD3, Cox2, and Ki-67. Nevertheless, the tendency towards decrease in the biomarker expression level has been observed for Ki67, and CD3. Conclusions: Morbidly obese women who present for bariatric surgery are at relatively high risk of harboring a premalignant condition of the endometrium. We are the first group to demonstrate that trends for improvement in several cancer associated markers can be achieved with weight loss, especially for CD20 and ER. Additional investigations of endometrial biomarker levels before and after bariatric surgery are needed in larger samples to evaluate if weight loss associated with bariatric surgery truly reduces the rate of uterine pathology. Citation Format: Faina Y. Linkov, Robert Edwards, Marina L. Komaroff, Esther Elishaev, Nika Gloyeske, Peter Argenta. Biomarker changes in the endometrium of morbidly obese women undergoing bariatric surgery: Implications for endometrial cancer risk reduction. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-26. doi:10.1158/1538-7445.AM2013-LB-26