Diabetes as a risk factor for death following endometrial cancer

Objective. To determine whether several personal or lifestyle risk factors for the occurrence of endometrial cancer are also risk factors for death following endometrial cancer. Methods. In 1986, we obtained risk factor information by mail on 41,836 women aged 55-69 years and living in Iowa. We followed those initially free of cancer through 2000 and identified incident endometrial cancers via linkage to a cancer registry. Women with endometrial cancer (n = 415) then were followed to identify overall and endometrial cancer deaths. Results. Over a median of 6.4 years following endometrial cancer diagnosis, 93 women died, 39 with endometrial cancer as the underlying cause. Among the various personal and lifestyle risk factors examined, only diabetes (self-reported) was related to death following endometrial cancer. Adjusted for age and extent of endometrial cancer at diagnosis, the relative risk of overall death for diabetic versus nondiabetic women was 2.79 (95% CI 1.63-4.78). For endometrial cancer as a specific cause of death, the diabetes-related relative risk was 2.38 (95% CI 1.05-5.37). Further adjustment for tumor grade strengthened these relative risks slightly. Conclusions. Diabetes is associated with poorer survival after incident endometrial cancer, independent of tumor stage and grade. Our findings raise the possibility of a diabetes-related condition, such as hyperglycemia or hyperinsulinemia, contributing to poorer endometrial cancer survival.