Factors associated with Type I and Type II endometrial cancer.

Objective: We investigated risk factors for Type II (n = 176) vs. Type I (n = 1,576) endometrial cancer (EC) in cases treated at Magee-Womens Hospital between 1996 and 2008.

Methods: Clinical data were available from the University of Pittsburgh Medical Center (UPMC) Network Cancer Registry. Logistic regression was used to estimate the adjusted odds of having Type II EC vs. Type I EC. Risk factors of interest in this analysis were age, race, body mass index (BMI), year of diagnosis, parity, menopausal status, and history of additional primary tumors.

Results: Relative to women with Type I EC, women with Type II EC were more likely to be older at diagnosis (OR: 1.03 per 1 year increase in age, 95% CI 1.01-1.05), of non-white race (OR: 2.95, 95% CI 1.66-5.27), have a history of additional primary tumors (OR: 1.56, 95% CI 1.05-2.32), and less likely to be obese (OR: 0.45, 95% CI 0.29-0.70).

Conclusion: In this large retrospective cohort of patients with EC, the striking difference in risk factors associated with Type II vs. Type I tumors suggests that these subtypes represent different disease entities that require different treatment modalities. Currently, Type II cases have a significantly worse prognosis compared to Type I. Further characterization of risk factors associated with developing Type II tumors is needed to prevent this aggressive malignancy.