Sentinel lymph node for endometrial cancer treatment: review of the literature

INTRODUCTION: Endometrial cancer is the most common gynecologic malignancy and in two thirds of patients it is apparently uterine confined at presentation. Lymph nodal status represents one of the main prognostic factors. Nodal evaluation with sentinel lymph node (SLN) mapping has gained more ground in clinical practice after the publication of different studies demonstrating the feasibility and accuracy of this technique. However, at the moment there are no RCTs available evaluating the long-term oncologic safety of SLN technique compared to LND. This review aims at summarizing the available evidence on oncologic outcomes between SLN mapping alone and LND. Differences in operative complications and long-term complications were also analyzed. EVIDENCE ACQUISITION: The literature search was conducted in the PubMed database and it focused on comparative studies published from inception to September 2020 analyzing differences in oncological outcomes or complications between nodal evaluation with SLN technique alone and nodal evaluation with lymphadenectomy. Comparative studies with more than 10 cases, published in English, were included. EVIDENCE SYNTHESIS: A total of 5 retrospective comparative studies have been identified reporting data on oncologic outcomes of patients who underwent SLN mapping alone vs. LND. Non significative difference has been reported in terms of overall survival and recurrence free survival between the two groups. Six studies evaluated differences in terms of complications between the two techniques. A total of 2302 patients were identified. Postoperative complications were detected in 9.6% and 7.7% of patients who underwent lymphadenectomy and SLN mapping respectively and no significant difference was noted (P=0.3). Looking at major postoperative complications the rate in the LND group was significantly higher than in the SLN group (3.6% vs. 1.5%, P=0.02). Two of these six studies reported data on lymphatic long-term complications. The prevalence of lymphedema ranged from 0% to 1.3% in the SLN group and from 10% to 18% in the LND group. The absolute difference reported (13.35%) was similar to the one found in literature. CONCLUSIONS: SLN mapping in apparently uterine confined disease has been demonstrated to be a feasible and accurate technique for nodal evaluation and high-quality evidence support this. Moreover, SLN mapping resulted to be associated with less major postoperative and long-term complications when compared to LDN. Conversely, high-quality evidence is not available on long-term oncologic safety of this technique compared to the standard LND. Randomized trials are requested to provide reliable data on this aspect.