Oncologic outcomes of sentinel lymph node mapping in patients with high-intermediate– and high-risk endometrial cancer: a systematic review and meta-analysis

Sentinel lymph node (SLN) mapping has not been widely adapted in the setting of high-intermediate and high-risk endometrial cancer. The goal of this study was to determine oncologic outcomes in this high-intermediate or high-risk population undergoing SLN mapping compared with systematic pelvic ± para-aortic lymphadenectomy. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, MEDLINE, Embase, and Cochrane databases were searched for trials comparing SLN with lymphadenectomy for patients with high- or high-intermediate-risk endometrial cancer. Studies were excluded if they lacked a control group, involved overlapping populations, were only available as abstracts, or were not in English. The main outcomes were overall survival, disease-free survival, recurrence, and adjuvant therapy rates. A pre-specified sub-group analysis was carried out that included high-risk patients, high-intermediate-risk patients, and only propensity score-matched studies. Statistical analysis was performed using RStudio Version 4.4.0. Heterogeneity was assessed using I2 statistics. A total of 10 observational studies (2 with population data from the National Center for Biotechnology Information - NCBI and the Surveillance, Epidemiology and End Results - SEER databases) were included, evaluating a total of 6127 patients. There were no randomized control trials. There were no differences regarding overall survival (HR 0.82, 95% CI 0.60 to 1.11, p = .19, I2 = 36%) or disease-free survival (HR 0.85, 95% CI 0.67 to 1.08, p = .19, I2 = 0%) between SLN mapping and lymphadenectomy. Recurrence rates (OR 0.79, 95% CI 0.58 to 1.06, p = .12, I2 = 0%) and adjuvant therapy (OR 1.39, 95% CI 0.78 to 2.48, p = .26, I2 = 85%) were also similar between the groups. In a sub-group analysis including only the high-risk population, a statistically significant difference in overall survival favored SLN mapping compared with the lymphadenectomy (OR 0.62, 95% CI 0.44 to 0.89, p < .01, I2 = 0%). Similarly, the analysis of propensity score-matched studies showed better overall survival in the SLN cohort (OR 0.61, 95% CI 0.43 to 0.87, p < .01, I2 = 0%). SLN mapping is associated with similar oncologic outcomes to lymphadenectomy in patients with high-intermediate and high-risk endometrial cancer. Routine lymphadenectomy should no longer be considered a standard of care.