Is body mass index an independent risk factor of survival among patients with endometrial cancer?

OBJECTIVE: To evaluate whether body mass index (BMI) is an independent risk factor for survival in patients with endometrial adenocarcinoma. METHODS: Women treated for endometrial cancer at the State University of New York (SUNY), Downstate and Kings County Hospital between January 1982 and September 2003 were eligible. Patients were divided into groups based upon their histology at the time of diagnosis. The first included patients with low-grade endometrioid adenocarcinoma (FIGO grades 1 and 2); the second included grade 3 endometrioid adenocarcinoma; and the third contained papillary serous and clear cell carcinomas. Data regarding BMI, patient age, race, grade, and stage of disease and overall survival, were assessed by survival analysis, with P < 0.05 considered significant throughout. RESULTS: The analysis included 442 patients. Mean BMI was 32.6 ± 8.2. There were 312 patients (70%) treated for low-grade endometrial adenocarcinoma; 64 patients (14%) for grade 3 endometrioid adenocarcinoma; and 71 patients (16%) for papillary serous and clear cell adenocarcinoma. Increased BMI was associated with improved overall survival (P = 0.003). BMI was also correlated to tumor grade, stage at diagnosis, age, and race. Tumor grade, stage, age, and race were correlated to survival. Statistical analyses revealed the majority of the association between BMI and survival can be attributed to the association between BMI and these other risk factors for survival in endometrial cancer. CONCLUSIONS: Increased BMI is associated with survival advantage among patients with endometrial cancer. Because of the relationship between obesity and other confounding variables obesity alone is not an independent predictor of survival.