Risk of endometrial cancer after insufficient endometrial biopsy: A retrospective cohort study.

Abstract

Background: Endometrial biopsies are used to diagnose abnormalities in the endometrium, but the biopsies are sometimes insufficient.

Objective: To evaluate the risk of detecting endometrial cancer in individuals with an insufficient endometrial index biopsy compared to individuals with a normal index biopsy.

Study design: In this retrospective cohort study, we used the Danish Pathology Register to identify individuals with endometrial biopsies between 2013 and 2017. We categorized initial and follow-up samples as either normal, insufficient, hyperplastic, or cancer by using SNOMED codes. We had 4 years of follow-up until December 31^st, 2021, and we compared categories with Kaplan-Meier analysis, a log-rank test, and Cox regression.

Results: A total of 80,761 Danish individuals were included. Out of these, 13,964 (17.3%) had an insufficient endometrial index biopsy, meaning the index sample contained too little tissue for a definitive diagnosis. From this group, 6,130 (43.9%) individuals had a follow-up endometrial biopsy performed. Unadjusted for age (HR 3.7; 95% CI 3.56-3.84), the incidence of endometrial cancer (n=368; 2.6%) was higher in individuals with an insufficient index biopsy compared to those with a normal index biopsy (n=423; 0.7%). However, when we adjusted for age, the hazard for endometrial cancer was only slightly higher after an insufficient biopsy compared to a normal biopsy (HR 1.16; 95% CI 1.02-1.31).

Conclusion: We found an increased risk of detecting endometrial cancer in individuals with an insufficient index biopsy compared to individuals with a normal index biopsy. After adjusting for age, the risk was only slightly increased.