Prospective evaluation of insulin resistance among endometrial cancer patients

OBJECTIVE: Obesity and estrogen are strong risk factors for endometrial cancer (EC). Whereas diabetes also increases the risk, little is known about related insulin resistance (IR). The purpose of this study was to determine the prevalence of IR in newly diagnosed EC patients. STUDY DESIGN: EC patients from a large, metropolitan county were prospectively enrolled from 2005 to 2008. Fasting serum was analyzed for glucose and insulin. IR was defined as a history of diabetes or a quantitative insulin sensitivity check index (QUICKI) (1/[log fasting insulin + log fasting glucose]) value of less than 0.357. RESULTS: Among 99 patients, diabetes was present in 30, and an abnormal QUICKI was found in 36 additional patients. Increased risk of IR was significantly associated with higher body mass index (P < .001), lower socioeconomic status (P = .007), and nulliparity (P = .029). CONCLUSION: IR was highly prevalent in endometrial cancer patients, including nonobese women. Better characterization of metabolic risks in addition to obesity may provide avenues for targeted cancer prevention in the future.