Comparison of endometrial cancer risk in patients with endometrial precancerous lesions: WHO 1994 vs EIN classification.

Our aim was to investigate the frequency of concurrent endometrial cancer in patients with endometrial precancerous lesions (PCLs) using World Health Organization 1994 (WHO94) and endometrial intraepithelial neoplasia (EIN) systems. We retrospectively investigated patients that underwent surgery for endometrial PCLs according to WHO94 or EIN systems at Hacettepe University Gynecology Clinic between January 2002 and June 2014. Of the 267 patients, 189 (70.9%) were in the WHO94 group, 78 (29.2%) were in the EIN group. Mean age of patients was 50.2 years. Sixteen patients (8.5%) in WHO94 group and 15 (%19.2) patients in the EIN group had EC (p = 0.013). In WHO94 group, EC rate in patients with atypical EH (32.6%) was significantly more than patients with non-atypical EH (1.4%) (