Comparison of a sentinel lymph node mapping algorithm and comprehensive lymphadenectomy in the detection of stage IIIC endometrial carcinoma at higher risk for nodal disease

Objective To determine if a sentinel lymph node (SLN) mapping algorithm will detect metastatic nodal disease in patients with intermediate −/high-risk endometrial carcinoma. Methods Patients were identified and surgically staged at two collaborating institutions. The historical cohort (2004–2008) at one institution included patients undergoing complete pelvic and paraaortic lymphadenectomy to the renal veins (LND cohort). At the second institution an SLN mapping algorithm, including pathologic ultra-staging, was performed (2006–2013) (SLN cohort). Intermediate-risk was defined as endometrioid histology (any grade), ≥ 50% myometrial invasion; high-risk as serous or clear cell histology (any myometrial invasion). Patients with gross peritoneal disease were excluded. Isolated tumor cells, micro-metastases, and macro-metastases were considered node-positive. Results We identified 210 patients in the LND cohort, 202 in the SLN cohort. Nodal assessment was performed for most patients. In the intermediate-risk group, stage IIIC disease was diagnosed in 30/107 (28.0%) (LND), 29/82 (35.4%) (SLN) (P = 0.28). In the high-risk group, stage IIIC disease was diagnosed in 20/103 (19.4%) (LND), 26 (21.7%) (SLN) (P = 0.68). Paraaortic lymph node (LN) assessment was performed significantly more often in intermediate −/high-risk groups in the LND cohort (P < 0.001). In the intermediate-risk group, paraaortic LN metastases were detected in 20/96 (20.8%) (LND) vs. 3/28 (10.7%) (SLN) (P = 0.23). In the high-risk group, paraaortic LN metastases were detected in 13/82 (15.9%) (LND) and 10/56 (17.9%) (SLN) (%, P = 0.76). Conclusions SLN mapping algorithm provides similar detection rates of stage IIIC endometrial cancer. The SLN algorithm does not compromise overall detection compared to standard LND.