BACKGROUND/OBJECTIVES: Given the risk of a progression, or an undiagnosed endometrial cancer (EC), the treatment of choice is hysterectomy in women with endometrial intraepithelial neoplasia (EIN). The risk of metastatic disease and whether sentinel node (SLN) biopsy should be performed remains unclear. The primary aim of this prospective study was to determine the overall incidence of concurrent EC and the impact of the diagnostic tool used and the type of endometrial lesion. The secondary aim was to investigate the risk of metastatic SLNs.

METHODS

Between July 2019 and May 2024, 98 consecutive women with EIN deemed suitable for robotic surgery and SLN dissection were included in the study. Ultrastaging and immunohistochemistry were performed on all SLNs.

RESULTS

In total, 47% of women with preoperative EIN had EC on final histology; 13% of these had metastatic SLNs and the overall risk of metastases was 6.3%. Women who obtained their diagnosis by an endometrial biopsy had 65% risk of EC. All women with metastatic SLNs had non-polypoid lesions and five out of six obtained their diagnosis through endometrial biopsy.

CONCLUSIONS

The overall risk of SLN metastases was 6.3%, all in women with a general endometrial thickening and/or a diagnosis of EIN by office endometrial biopsy, suggesting that SLN detection should be offered particularly to women with EIN who fulfill these preoperative criteria.