Abstract AP06: METABOLIC SYNDROME AND RISK OF OVARIAN CANCER IN THE UNITED STATES: AN ANALYSIS OF LINKED SEER–MEDICARE DATA
Authors: Michels Kara A. , Trabert Britton 
Published: June 2021

BACKGROUND: Ovarian cancer is typically diagnosed at later stages and we have much to learn regarding its etiology. Identifying modifiable risk factors has the potential to reduce the burden of ovarian cancer. Metabolic dysregulation is thought to play a role in the development of this disease, but associations between risk of ovarian cancer and markers of metabolic dysregulation are inconsistent across studies (e.g., diagnoses of metabolic syndrome or diabetes, measurement of circulating lipids). Many studies are not able to evaluate associations across subtypes of ovarian cancer, which is crucial given our knowledge about the heterogeneous etiologies of ovarian cancer histotypes.

PURPOSE: Using data from U.S. women who were eligible for Medicare, we estimated risk of ovarian cancer associated with metabolic syndrome and its components, as documented in medical records. We also determined if these associations differed by histotype.

METHODS: We created a case-control study within the Surveillance, Epidemiology and End Results (SEER)–Medicare linked database. Cases (n = 16,850) were women diagnosed with epithelial ovarian or fallopian tube cancer between ages 70 to 90 from 1994 through 2013. Controls (n = 281,878) were a 5% sample of female Medicare enrollees residing in the same SEER registry area as cases. Cases and controls were required to be enrolled in Medicare for at least 1 year continuously during the 2 to 3 years before an index date (date of diagnosis for cases, randomly selected date for controls). We examined whether factors related to metabolic syndrome (obesity, fasting glucose, high blood pressure, HDL cholesterol, triglycerides), individually or combined (using several standard definitions of metabolic syndrome), were associated with ovarian cancer. These factors were defined using ICD-9-CM codes from inpatient/outpatient diagnoses during the 2 to 5 years before the index dates. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression adjusted for index date, age, race, registry, smoking status, and state buy-in status.

RESULTS: Medical record documentation of high blood pressure (OR 1.06, 95%CI 1.03–1.10) and high triglycerides (OR 1.11, 95%CI 1.07–1.15) were associated with modestly increased risk of ovarian cancer. Metabolic syndrome was not associated with risk overall. High blood pressure increased risk of endometrioid (OR 1.19, 95%CI 1.05–1.35) and clear cell tumors (OR 1.25, 95% CI 1.01–1.55). High triglycerides consistently increased risk across histotype and grade. We identified reduced risks for serous cancer with high fasting glucose (OR 0.88, 95% CI 0.83–0.94); this association strengthened when limiting to high-grade serous tumors (OR 0.80, 95% CI 0.74–0.86).

CONCLUSIONS: Our data suggest that individual components of metabolic syndrome are associated with ovarian cancer, rather than metabolic syndrome itself. For serous cancers, we saw associations in different directions for elevated triglycerides and fasting glucose—indicating that evaluating metabolic syndrome as a composite outcome could be misleading and etiologically uninformative in ovarian cancer studies. While both lipid and glucose metabolism can be dysregulated in metabolic syndrome, the consequences of this dysregulation likely influence the development of serous ovarian cancers via different mechanisms.

Citation Format: Kara A. Michels, Britton Trabert. METABOLIC SYNDROME AND RISK OF OVARIAN CANCER IN THE UNITED STATES: AN ANALYSIS OF LINKED SEER–MEDICARE DATA [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP06.