Outcomes for patients with high-risk endometrial cancer undergoing sentinel lymph node assessment versus full lymphadenectomy.

Objective: The objective of this study was to determine the progression free survival (PFS) and overall survival (OS) among patients with high-risk endometrial cancer (EC) who underwent sentinel lymph node (SLN) mapping and dissection compared to patients who underwent pelvic +/- para-aortic lymphadenectomy (LND).

Methods: Patients with newly diagnosed high-risk EC were identified. Inclusion criteria included patients who underwent primary surgical management from January 1, 2014 to September 1, 2020 at our institution. Patients were categorized into either the SLN or LND group based on their method of planned lymph node assessment. Patients in the SLN group had dye injected followed by successful bilateral lymph node mapping, retrieval, and processing per our institutional protocol. Clinicopathological and follow-up data were extracted from patient's medical records. The t-test or Mann-Whitney test was used to compare continuous variables and Chi-squared or Fisher's exact test were used for categorical variables. Progression-free survival (PFS) was calculated from the date of initial surgery to the date of progression, death, or last follow-up. Overall survival (OS) was calculated from the date of surgical staging to the date of death or last follow-up. Three-year PFS and OS were calculated using the Kaplan-Meier method, and the log-rank test was used to compare cohorts. Multivariable Cox regression models were used to assess the relationship between nodal assessment cohort and OS/PFS while adjusting for age, adjuvant therapy, and surgical approach. A result was considered statistically significant at the p < 0.05 level of significance and all statistical analysis was done using SAS version 9.4 (SAS Institute, Cary, NC).

Results: Out of 674 patients diagnosed with EC during the study period, 189 were diagnosed with high-risk EC based on our criteria. Forty-six (23.7%) patients underwent SLN assessment and 143 (73.7%) underwent LND. No difference was observed between the two groups in regards to age, histology, stage, body mass index, tumors myometrial invasion, lymphovascular space invasion, or peritoneal washing positivity. Patients in the SLN group underwent robotic-assisted procedures more frequently than those in the LND group (p < 0.0001). The three-year PFS rate was 71.1% (95% CI 51.3-84.0%) in the SLN group and 71.3% (95% CI 62.0-78.6%) in the LND group (p = 0.91). The unadjusted hazard ratio (HR) for recurrence in the SLN versus LND group was 1.11 (95% CI 0.56-2.18; p = 0.77), and after adjusting for age, adjuvant therapy, and surgical approach, the HR for recurrence was 1.04 (95% CI 0.47-2.30, p = 0.91). The three-year OS rate was 81.1% (95% CI 51.1-93.7%) in the SLN group and 95.1% (95% CI 89.4-97.8%) in the LND group (p = 0.009). Although the unadjusted HR for death was 3.74 in the SLN vs LND group (95% CI 1.39-10.09; p = 0.009), when adjusted for age, adjuvant therapy, and surgical approach, it was no longer significant with a HR of 2.90 (95% CI 0.94-8.95, p = 0.06).

Conclusions: There was no difference in three-year PFS in patients diagnosed with high-risk EC who underwent SLN evaluation compared to those who underwent full LND in our cohort. The SLN group did experience shorter unadjusted OS; however, when adjusting for age, adjuvant therapy and surgical approach, there was no difference OS in patients who underwent SLN compared to LND.