Factors associated with Type I and Type II endometrial cancer in a large cohort of cases

Objective: The goal of this study was to evaluate risk factor differences between two endometrial cancer (EC) subtypes in a large cohort of patients.

Methods: We conducted a retrospective study comparing Type I (N=1,576) and Type II (N=176) EC cases treated at Magee-Womens hospital between 1996 and 2008. Clinical data were available from the University of Pittsburgh Medical Center Network Cancer Registry. Logistic regression analysis was used to calculate the adjusted odds of being diagnosed with Type II EC compared to Type 1 EC. The factors of interest in this analysis were: age, BMI, race, year of diagnosis, parity, menopausal status, and history of additional primaries.

Results: Predictors significantly associated with Type II EC were older age at diagnosis (OR: 1.03, 95% CI 1.02-1.05), non-white race (OR: 2.95, 95% CI 1.66-5.27), obesity (OR: 0.45, 95% CI 0.29-0.70), and history of additional primaries (OR: 1.56, 95% CI 1.05-2.32).

Conclusions: This registry-based study is the most updated evaluation of factors associated with Type I and Type II EC in a large retrospective cohort of patients. The striking difference in risk factors associated with Type I vs. Type II tumors further emphasizes that these subtypes represent different disease entities, potentially requiring different treatment modalities.

Implications for public health: Endometrial cancer is the most common gynecologic malignancy in the U.S. Type II tumors account for a disproportionate amount of EC-related deaths; therefore, an understanding of the etiology of this aggressive disease can lead to prevention opportunities.