The incidence of neoplasm of uncertain behavior of uterus diagnosed after surgery for presumed leiomyoma: A national population-based study.

OBJECTIVE

To investigate the incidence of neoplasm of uncertain behavior of uterus (NUBU) diagnosed after hysterectomy, myomectomy, or hysteroscopy for presumed leiomyomas.

METHODS

We performed this population-based retrospective cohort study using the Korean national health insurance database between January 2002 and December 2018. Women with or without NUBU diagnosed after surgery were extracted using diagnosis codes and procedure codes.

RESULTS

The median age of patients who underwent surgery for presumed leiomyomas was 39 years (interquartile range [IQR] 31-47 years). The median age of women diagnosed with NUBU after surgery was 45 years (IQR 38-49 years). The incidence of NUBU diagnosed after surgery for presumed leiomyomas was 1.89%. The incidences of NUBU diagnosed after hysterectomy, myomectomy, or hysteroscopic myomectomy for presumed leiomyomas were 2.03%, 1.84%, or 1.64%, respectively. There was no difference in the incidence of NUBU according to these surgical methods.

CONCLUSIONS

Regardless of the surgical procedure performed, the incidence of NUBU diagnosed after surgery was higher than that of unexpected uterine malignancy diagnosed after hysterectomy (0.19%), myomectomy (0.12%), or hysteroscopic myomectomy (0.86%) for presumed leiomyoma. Compared with unexpected uterine malignancy, NUBU seems to occur in relatively young women.