Introduction/Background Endometrial cancer (EC) is the most common gynecological malignancy worldwide, with an estimated 382,069 new cases and 89,929 deaths in 2018. Lymph node involvement represents one of the most important prognostic factors and guides better planning of post-operative adjuvant treatment. Whereas lymph node assessment has been included in surgical staging since 1988, the optimal procedure for lymph node evaluation is controversial, ranging from full pelvic and para-aortic lymph node dissection (LND) to complete omission of LND. We previously evaluated the oncologic outcomes of 472 cases of EC (SLN with LND vs. LND alone) and demonstrated significantly lower likelihood of pelvic side-wall recurrences in patients who underwent SLN. These data raised the possibility that addition of SLN biopsy may not just be equivalent to conventional staging but may actually increase the detection of metastatic disease, resulting in better stratification of patients into risk groups, optimal adjuvant therapy prescription and as a result, better oncologic outcomes. In this study, we investigated the long-term oncological outcome of adding SLN to pelvic LND in patients with EC.

Methodology Retrospective study comparing survival outcomes (overall survival (OS), disease-specific survival (DSS), progression-free survival (PFS), recurrence-free survival) between endometrial cancer patients undergoing surgical staging, which included LND with or without SLN in non-overlapping contiguous eras. Hazard ratios (HR) and their respective 95% confidence intervals (95%CI) were calculated using Cox proportional hazard models.

Results 193 patients underwent LND and 250 patients had SLN mapping prior to LND. Clinical characteristics, including adjuvant therapy use, were similar between groups. During a median follow-up period of 6.9 years, addition of SLN was associated with more favorable oncological outcomes compared to LND with 6-year OS of 90% compared to 81% (p=0.009), and PFS of 85% compared to 75% (p=0.01) respectively. SLN was associated with improved OS (HR 0.5, 95% CI 0.3–0.8, p=0.004), DSS (HR 0.5, 95%CI 0.2–1.0, p=0.05) and PFS (HR 0.6, 95% CI 0.4–0.9, p=0.03) in a multivariable analysis as well, adjusted for age, ASA score, stage, grade, non-endometrioid histology, and LVSI. Patients who were staged with SLN were less likely to have a recurrence in the pelvis or lymph node basins compared to patients who underwent LND only (6-year recurrence-free survival 95% vs 90%, p=0.04).

Conclusion Addition of SLN was associated with improved clinical outcomes compared to LND alone in patients with endometrial cancer undergoing surgical staging.

Disclosures We have no disclosures.