Lower uterine segment involvement in lymphovascular space invasion and lymph node metastasis in endometrioid endometrial cancer.

Objectives: To evaluate the correlation between lymphovascular space invasion (LVSI) indicating lower uterine segment involvement (LUSI) in endometrioid endometrial cancer and lymph node metastasis based on the lymphatic drainage difference between the uterine corpus and the lower segment.

Material And Methods: Patients who underwent staging surgery for endometrioid endometrial cancer between January 2010 and January 2019 at our institution were reviewed. The clinicopathologic findings and LUSI status of the patients were compared with their LVSI and lymph node metastasis status.

Results: Of the 253 patients included in this study, 49 (19.4%) had LUSI. Among these patients, none of the 31 LVSI-negative patients had metastatic lymph node involvement. However, of the 18 LVSI-positive patients, half had metastatic lymph node involvement; this difference was significant (p < 0.05).

Conclusions: The significant correlation between LVSI and lymph node metastasis in LUSI-positive cases indicates that pathologists should also focus on LVSI findings in the frozen examination required for the decision of staging surgery in patients with endometrioid endometrial cancer limited to the uterus. This is especially important in patients with a lower uterine segment involvement.