utilization and Outcomes of Sentinel Lymph Node Biopsy for Early Endometrial Cancer

OBJECTIVE: To examine trends, characteristics, and oncologic outcomes of sentinel lymph node biopsy for early endometrial cancer. METHODS: This observational study queried the National Cancer Institute's Surveillance, Epidemiology, and End Results Program by examining 83,139 women with endometrial cancer who underwent primary hysterectomy with nodal evaluation for T1 disease from 2003 to 2018. Primary outcome measures were the temporal trends in utilization of sentinel lymph node biopsy and patient characteristics associated with sentinel lymph node biopsy use, assessed by multivariable binary logistic regression models. Secondary outcome measure was endometrial cancer-specific mortality associated with sentinel lymph node biopsy, assessed by propensity score inverse probability of treatment weighting. RESULTS: The utilization of sentinel lymph node biopsy increased from 0.2 to 29.7% from 2005 to 2018 (P<.001). The uptake was higher for women with endometrioid (0.3-31.6% between 2005 and 2018) compared with nonendometrioid (0.6-21.0% between 2006 and 2018) histologic subtypes (both P<.001). In a multivariable analysis, more recent year surgery, endometrioid histology, well-differentiated tumors, T1a disease, and smaller tumor size were independently associated with sentinel lymph node biopsy use (P<.05). Performance of sentinel lymph node biopsy was not associated with increased endometrial cancer-specific mortality compared with lymphadenectomy for endometrioid tumors (subdistribution hazard ratio [HR] 0.96, 95% CI 0.82-1.13) or nonendometrioid tumors (subdistribution HR 0.85, 95% CI 0.69-1.04). For low-risk endometrial cancer, the increase in sentinel lymph node biopsy resulted in a 15.3 percentagepoint (1.4-fold) increase in surgical nodal evaluation by 2018 (expected vs observed rates, 37.8 vs 53.1%). CONCLUSION: The landscape of surgical nodal evaluation is shifting from lymphadenectomy to sentinel lymph node biopsy for early endometrial cancer in the United States, with no indication of a negative effect on cancerspecific survival.