The added value of SLN mapping with indocyanine green in low- and intermediate-risk endometrial cancer management: a systematic review and meta-analysis

OBJECTIVE: The aim of this study was to assess the SLN detection rate in presumed early stage, low- and intermediate-risk endometrial cancers, the incidence of SLN metastases, and the negative predictive value of SLN mapping performed with indocyanine green (ICG). METHODS: A systematic review with meta-analyses was conducted. Study inclusion criteria were A) low- and intermediate-risk endometrial cancer, B) the use of ICG per cervical injection; C) a minimum of twenty included patients per study. To assess the negative predictive value of SLN mapping, D) a subsequent lymphadenectomy was an additional inclusion criterion. RESULTS: Fourteen studies were selected, involving 2,117 patients. The overall and bilateral SLN detection rates were 95.6% (95% confidence interval [CI]=92.4%–97.9%) and 76.5% (95% CI=68.1%–84.0%), respectively. The incidence of SLN metastases was 9.6% (95% CI=5.1%–15.2%) in patients with grade 1–2 endometrial cancer and 11.8% (95% CI=8.1%–16.1%) in patients with grade 1–3 endometrial cancer. The negative predictive value of SLN mapping was 100% (95% CI=98.8%–100%) in studies that included grade 1–2 endometrial cancer and 99.2% (95% CI=97.9%–99.9%) in studies that also included grade 3. CONCLUSION: SLN mapping with ICG is feasible with a high detection rate and negative predictive value in low- and intermediate-risk endometrial cancers. Given the incidence of SLN metastases is approximately 10% in those patients, SLN mapping may lead to stage shifting with potential therapeutic consequences. Given the high negative predictive value with SLN mapping, routine lymphadenectomy should be omitted in low- and intermediate-risk endometrial cancer.