Sentinel Lymph Node Procedures In Endometrial Cancer: An International Multicenter Experience

Objectives: Lymphadenectomy as part of surgical staging for endometrial cancer can define risk of recurrence and guide clinical decision-making for adjuvant therapy. While sentinel lymph node (SLN) mapping significantly reduces surgical complications and conserves an element of staging, its clinical significance remains controversial. The purpose of this study was to evaluate the incidence of SLN metastases and to identify risk factors and outcomes associated with positive SLNs. Methods: An international population-based retrospective review in three tertiary care academic centers was conducted on patients with endometrial cancer undergoing SLN biopsy as part of surgical staging for apparent early stage endometrial cancer. Multivariate logistic regression was performed to assess predictors of SLN positivity and to estimate the effect of SLN metastases on overall survival (OS) and progression-free survival (PFS). Results: One thousand and twelve patients were included with an average age of 60 years (24-90). The majority of women had Stage IA (68.9%) and low-grade histology (76.9%). Indocyanine green was used to identify SLNs in 535 (52.9%) women with an overall uptake at the whole-patient level of 94.0%. The overall incidence of SLN metastases was 5.7% (n=58). Cancer Antigen 125 > 35U/mL (OR=3.8 95% CI: 1.4-10.5; p=0.013) and presence of lymphovascular space invasion (OR=15.8, 95% CI: 5.6-44.7; p<0.001) were associated with SLN positivity. The three-year OS and PFS probabilities were 95.8% (95% CI: 93.8-97.8) and 91.1% (95% CI: 88.6-93.6) in the SLN negative group (p=0.032), and 91.6% (95% CI: 82.4-100.0) and 86.5% (95% CI: 75.3-97.7) in the SLN positive group (p=0.433), respectively. Conclusions: This is the largest international multicentered study evaluating SLN identification in endometrial cancer. Cancer Antigen 125 was identified as a preoperative independent risk factor associated with SLN positivity and can be used to optimize patient selection and surgical planning. Our data support the current literature suggesting that SLN biopsy for endometrial cancer should become standard of care. The procedure is associated with minimal morbidity and mortality, and has excellent performance. Lymphadenectomy as part of surgical staging for endometrial cancer can define risk of recurrence and guide clinical decision-making for adjuvant therapy. While sentinel lymph node (SLN) mapping significantly reduces surgical complications and conserves an element of staging, its clinical significance remains controversial. The purpose of this study was to evaluate the incidence of SLN metastases and to identify risk factors and outcomes associated with positive SLNs. An international population-based retrospective review in three tertiary care academic centers was conducted on patients with endometrial cancer undergoing SLN biopsy as part of surgical staging for apparent early stage endometrial cancer. Multivariate logistic regression was performed to assess predictors of SLN positivity and to estimate the effect of SLN metastases on overall survival (OS) and progression-free survival (PFS). One thousand and twelve patients were included with an average age of 60 years (24-90). The majority of women had Stage IA (68.9%) and low-grade histology (76.9%). Indocyanine green was used to identify SLNs in 535 (52.9%) women with an overall uptake at the whole-patient level of 94.0%. The overall incidence of SLN metastases was 5.7% (n=58). Cancer Antigen 125 > 35U/mL (OR=3.8 95% CI: 1.4-10.5; p=0.013) and presence of lymphovascular space invasion (OR=15.8, 95% CI: 5.6-44.7; p<0.001) were associated with SLN positivity. The three-year OS and PFS probabilities were 95.8% (95% CI: 93.8-97.8) and 91.1% (95% CI: 88.6-93.6) in the SLN negative group (p=0.032), and 91.6% (95% CI: 82.4-100.0) and 86.5% (95% CI: 75.3-97.7) in the SLN positive group (p=0.433), respectively. This is the largest international multicentered study evaluating SLN identification in endometrial cancer. Cancer Antigen 125 was identified as a preoperative independent risk factor associated with SLN positivity and can be used to optimize patient selection and surgical planning. Our data support the current literature suggesting that SLN biopsy for endometrial cancer should become standard of care. The procedure is associated with minimal morbidity and mortality, and has excellent performance.