Antidiabetic Medication, Statins and the Risk and Prognosis of Non-endometrioid Endometrial Cancer in Women with Type 2 Diabetes

Aim: To determine the incidence and prognosis of non-endometrioid endometrial cancer (EC) in relation to the use of metformin, other antidiabetic medication (ADM) and statins in patients with type 2 diabetes (T2D). Materials and Methods: In order to analyze the incidence and prognosis of non-endometrioid EC, two cohorts were obtained from a nationwide diabetes database (FinDM); 57 non-endometrioid ECs were observed in a cohort of 92,366 women with newly-diagnosed T2D during the follow-up (1996 to 2011) to assess the incidence, and a retrospective cohort of 105 women with T2D diagnosed with non-endometrioid EC (1998 to 2011) was used to estimate cumulative mortality from EC and other causes of death. Hazard ratios (HRs) with 95% confidence intervals (CIs) for EC incidence were estimated in the full-cohort analysis and in the nested case-control analysis, matched for age and duration of T2D. Cumulative mortality was estimated by using the Aalen-Johansen estimator. Cause-specific mortality rates were analyzed by using Cox models regarding the pre-diagnostic use of different forms of ADM and statins. Results: In the nested case-control analysis, the use of metformin was not associated with the risk of nonendometrioid EC (HR=1.09, 95% CI=0.59-2.00), whereas statin use was associated with a lower risk (HR=0.47, 95% CI=0.26-0.84). The results from the full-cohort analysis supported these findings. Mortality from non-endometrioid EC was not different between users of metformin and other types of oral ADM (HR=1.56, 95% CI=0.40-6.07) but was observed to be lower in statin users (HR=0.41, 95% CI=0.20-0.82). Conclusion: Our findings were inconclusive regarding the association of metformin with the risk and prognosis of non-endometrioid EC. However, statin use was associated with a lower incidence and mortality from this disease.