Overall survival after surgical staging by lymph node dissection versus sentinel lymph node biopsy in endometrial cancer: a national cancer database study

OBJECTIVE: Substituting lymphadenectomy with sentinel lymph node biopsy for staging purposes in endometrial cancer has raised concerns about incomplete nodal resection and detrimental oncological outcomes. Therefore, this study aimed to investigate the association between the type of lymph node assessment and overall survival in endometrial cancer accounting for node status and histology. METHODS: Women with stage I-III endometrial cancer who underwent hysterectomy and lymph node assessment from January 2012 to December 2015 were identified in the National Cancer Database. Patients who underwent neoadjuvant therapy, had previous cancer, and whose follow-up was less than 90 days were excluded. Multivariable Cox proportional hazards regression analyses were performed to assess factors associated with overall survival. RESULTS: Of 68 614 patients, 64 796 (94.4%) underwent lymphadenectomy, 1777 (2.6%) underwent sentinel node biopsy only, and 2041 (3.0%) underwent both procedures. On multivariable analysis, neither sentinel lymph node biopsy alone nor sentinel node biopsy followed by lymphadenectomy was associated with significantly different overall survival compared with lymphadenectomy alone (HR 0.92, 95% CI 0.73 to 1.17, and HR 0.91, 95% CI 0.77 to 1.08, respectively). When stratified by lymph node status, sentinel node biopsy alone or followed by lymphadenectomy was not associated with different overall survival, both in patients with negative (HR 0.95, 95% CI 0.73 to 1.24, and HR 1.04, 95% CI 0.85 to 1.27, respectively) or positive (HR 0.91, 95% CI 0.54 to 1.52, and HR 0.77, 95% CI 0.57 to 1.04, respectively) lymph nodes. These findings held true when sentinel node biopsy alone and sentinel node biopsy plus lymphadenectomy groups were merged, and on stratification by histotype (type one vs type 2) or inclusion of only complete lymphadenectomy (at least 10 pelvic nodes and at least one para-aortic node removed). In all analyses, age, Charlson-Deyo score, black race, AJCC pathological T stage, grade, lymphovascular invasion, brachytherapy, and adjuvant chemotherapy were independently associated with overall survival. DISCUSSION: No difference in overall survival was found in patients with endometrial cancer who underwent sentinel node biopsy alone, sentinel node biopsy followed by lymphadenectomy, or lymphadenectomy alone. This observation remained regardless of node status, histotype, and lymphadenectomy extent.