Incidence of endometrial carcinoma in patients with endometrial intraepithelial neoplasia versus atypical endometrial polyp

Objective Our study's primary aim was to compare the incidence of endometrial carcinoma in patients with a presurgical diagnosis of endometrial intraepithelial neoplasia confined to the endometrium (EIN-E) versus endometrial intraepithelial neoplasia confined to a polyp (EIN-P). Our secondary aim was to examine the difference in pathological features, prognostic risk groups and sentinel lymph node involvement between the two groups. Methods We conducted a retrospective cohort study between January 2014 and December 2020 in a tertiary university-affiliated medical center. The study considered the characteristics of women who underwent hysterectomy with sentinel lymph node dissection for endometrial intraepithelial neoplasia (EIN). We compared EIN-E diagnosed by endometrial sampling via dilatation curettage or hysteroscopic curettage vs EIN-P. A multivariate logistic regression analysis was used to assess risk factors for endometrial cancer. Results Eighty-eight women were included in the study, of those, 50 were women with EIN-P (EIN-P group) and 38 were women with EIN following an endometrial biopsy (EIN-E group). The median age was 57.5 years (range; 52-68) in the EIN-P group as compared with 63 years (range; 53-71) in the EIN-E group (p=0.47). Eighty-nine percent of the women in the EIN-E group presented with abnormal uterine bleeding whereas 46% of the women in the EIN-P group were asymptomatic (p=0.001). Pathology results following hysterectomy revealed concurrent endometrial carcinoma in 26% of women in the EIN-P group compared with 47% of women in the EIN-E group (p=0.038). Multivariate analysis showed that endometrial cancer was significantly less common in the EIN-P group (overall response (OR)=0.3 95% confidence interval (CI)=0.1-0.9, p=0.03). Eighty-four percent of cancers were grade one in the EIN-P group compared with 50% in the EIN-E group (p=0.048). Conclusions Concurrent endometrial cancer is less frequent with EIN-P than with EIN-E. The high incidence of endometrial carcinoma in both groups supports the current advice to perform hysterectomy for post-menopausal women. Our data does not support performing sentinel lymph node dissection for EIN-P that was completely resected. The benefit of sentinel lymph node dissection for women with pre-operative EIN-E is yet to be determined.