Abstract C069: Body mass index, race, and ovarian cancer: Characterizing changes after diagnosis and associations with overall survival

Abstract

Abstract Background: Obesity has been implicated in the progression of ovarian cancer, but associations between body mass index (BMI) and survival outcomes are mixed. Studies evaluating pre- or peri-diagnosis BMI have generally found associations between higher BMI and worse overall survival (OS), but studies with post-diagnosis BMI measures are limited. Furthermore, no existing post-diagnosis BMI and ovarian cancer survival studies have conducted analyses stratified by race. Objective: We undertook this study to characterize changes over time in BMI among ovarian cancer cases from the Vanderbilt University Medical Center (VUMC) and to evaluate associations in relation to overall survival (OS); differences by race were examined in stratified analyses. Methods: We assembled a retrospective cohort of Tumor Registry confirmed ovarian cancer cases from VUMC EMR. BMI (kg/m2) at diagnosis, and 6, 12, 18, and 24 months after diagnosis (±8 weeks) were used to classify obesity according to the World Health Organization (WHO) guidelines as underweight (<18.5), normal weight (<25), overweight (<30), or obese (≥30.0). BMI changes over time were determined by the ratio of the last to first available measure, and categorized as increased (>1.05%), decreased (<0.95), or stable (reference). Associations with OS were quantified by Hazard Ratios (HRs) and 95% Confidence Intervals (CIs) from Cox proportional-hazards regression in multivariable adjusted race-stratified analyses. Results: Among 380 ovarian cancer cases with peri- or post-diagnosis BMI measures available from EMR, the relative prevalence of WHO normal weight cases decreased over time (diagnosis: 40.4%; 6 months: 38.2%; 12 months: 35.5%; 18 months: 27.7%; 24 months: 22.8%); there were more cases who had a decreased BMI (46.6%) than increased BMI (28.4%). Neither the prevalence nor percent of patients with changes differed by race. Among Caucasians (86.8%), a BMI increase was associated with a decreased risk of death (HR: 0.62, 95% CI: 0.40-0.97) while a BMI decrease was associated with an increased risk of death (HR: 2.18, 95% CI: 1.51-3.17). However, this seemed to differ among African Americans (6.1%), where both an increased and decreased BMI tended to have worse OS. Conclusions: Changes in BMI after a diagnosis of ovarian cancer may have different associations with mortality by race. To further expand upon these preliminary findings, our next steps include conducting analysis with time-varying covariates and identifying collaborators with ovarian cancer cases who have post-diagnosis BMI measures available for additional analysis. Citation Format: Alicia Beeghly-Fadiel, Nneka J Anyanwu, Shyria Karam, Demetra Hufnagel, George Bukenya, Sara Duque, Deok Son, Andrew J Wilson, Marta A Crispens. Body mass index, race, and ovarian cancer: Characterizing changes after diagnosis and associations with overall survival [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C069.