The incidence of unexpected uterine malignancy in women undergoing hysteroscopic myomectomy or polypectomy: A national population-based study

Objective: The objective of this study was to investigate the incidence of unexpected uterine malignancy (UUM) diagnosed after hysteroscopic surgery for presumed submucosal leiomyomas or endometrial polyps. Study design: From the Korean national health insurance database between January 1, 2009 and December 31, 2015, we analyzed inpatient sample data that were extracted by a stratified random sampling (gender and age) method. We extracted women with or without UUM that was diagnosed after hysteroscopic surgery using diagnosis codes and procedure codes. Results: A total of 11,866 women who underwent hysteroscopic surgery were extracted from 4,476,495 women. The mean age of the patients who underwent hysteroscopic surgery was 37.8 ± 0.1 years. A hysteroscopic myomectomy or polypectomy was performed in 3498 and 8368 women, respectively. The incidence of UUM diagnosed after hysteroscopic myomectomy or polypectomy was 0.86% and 1.11%, respectively. The logistic regression analysis showed that the risk of UUM increased with age (Odds Ratio (OR), 1.61; 95% Confidence Interval (CI), 1.47–1.77; P < 0.001) and did not indicate hysteroscopic myomectomy or polypectomy (OR, 1.21; 95% CI, 0.93–1.55; P = 0.151). Conclusions: The incidence of UUM diagnosed after hysteroscopic myomectomy (0.86%) or polypectomy (1.11%) was higher than that of UUM diagnosed after hysterectomy (0.19%) or myomectomy (0.12%) for presumed benign leiomyoma. The incidence of UUM increased over the age of 50.