Incorporation of a Sentinel Lymph-Node Mapping Algorithm in Patients with Clinical Stage-I Endometrial Cancer

Objective: Sentinel lymph-node biopsy (SLNB) is now as alternative to pelvic and para-aortic lymph-node dissection (PPALND) for managing endometrial cancers. These data have been largely published from high-volume specialized institutions, but complete PPALND is still performed by many surgeons at smaller nonspecialized centers. The aim of this research was to demonstrate that SLNB is feasible, reproducible, and sensitive without affecting cancer-specific outcomes when implemented at nonspecialized centers.Materials and Methods: Cases of patients with clinical stage-I endometrial cancer were retrospectively reviewed from September 2016 through February 2020. Endometrioid, uterine papillary serous (UPSC), malignant mixed-mesodermal tumor (MMMT), and clear-cell (CC) histologies were included. All patients had undergone either robot-assisted or laparoscopic hysterectomies with SLNB. Indocyanine green was injected into the cervix bilaterally. Per the algorithm, patients with suboptimal lymph-node mapping or nodes suspicious for metastasis underwent a side-specific pelvic lymph-node dissection (LND). Para-aortic LND was performed at the discretion of the surgeon. In addition to SLNB, PPALND was performed for patients with MMMT, UPSC, or CC. Sentinel lymph nodes (SLNs) were evaluated using ultrastaging protocols with serial sectioning and cytokeratin staining. The medical records were queried for clinical or radiographic evidence of recurrences.Results: A total of 92 cases were included: 69 stage IA; 12 stage IB; 3 stage II; and 8 stage III (2 IIIA, 2 IIIC1, 4 IIIC2). The majority of cancers were endometrioid (73%), followed by UPSC (15.0%), MMMT (5.0%), and CC (4%). At least 1 SLN was detected in 95.4% of cases. The rate of bilateral SLN detection was 74.3% and improved over time from 2017 to 2019: 70% (2017); 74.4% (2018); and 80% (2019). Twenty patients underwent PPALND. Non-SLNs were positive in 3 patients, all with high-risk histologies. No other patients had false-negative SLNs. No recurrences occurred in this cohort with a median follow-up of 22 months.Conclusions: SLNB is a sensitive and specific method for assessing lymph-node involvement in patients with clinical stage-I endometrial cancers. These results are comparable to the rates reported in the literature and shows that, in nonspecialized centers, this approach is safe and reproducible without affecting cancer-specific outcomes. (J GYNECOL SURG 20XX:000)