OBJECTIVE: To evaluate the influence of body mass index (BMI) on endometrial tumor pathology, stage and complication rate and to identify individual prognostic factors, such as BMI, in types I and II endometrial cancer.

DESIGN: Register study included all Danish women who underwent surgery for uterine cancer or atypical endometrial hyperplasia (International Classification of Diseases-10 codes D070, DC549) 2005 to 2012 (n = 6003).

MAIN OUTCOME MEASURES: Impact of BMI on type I and II endometrial cancer survival.

MATERIALS AND METHODS: Danish Gynecological Cancer Database data on women with type I and II endometrial cancer were retrieved. Kaplan-Meier plot was used to illustrate differences in survival in relation to BMI. Log-rank test was used to demonstrate difference between the curves. Cox regression hazard model was used to estimate hazard ratios (HR) of the effect of BMI on overall survival.

RESULTS: Four thousand three hundred thirty women were included. Women with type I cancer had a significantly better overall survival compared with those with type II cancer. Low BMI was associated with increased mortality in type I (HR, 2.07; 95% confidence interval [CI], 1.20-3.55), whereas in type II both low (HR, 1.68; 95% CI, 1.03-2.74) and high BMI (BMI, 30-35: HR, 1.54; 95% CI, 1.01-2.26 and BMI >40: HR, 2.15; 95% CI, 1.12-4.11) were significantly associated with increased mortality.

CONCLUSION: Abnormal BMI is associated with increased mortality in subtypes of endometrial cancer. Underweight was associated with increased overall mortality in both types I and II, whereas obesity only disclosed a significant impact on overall mortality in type II.