Risk factors for sentinel lymph node involvement in patients with apparent early-stage endometrial cancer: a retrospective single-center study

Introduction/Background Sentinel lymph node (SLN) mapping with indocyanine green (ICG) has become the standard of care in apparent early-stage endometrial cancer. The aim of this study is to evaluate the possible risk factors (RFs) for lymph-nodal metastases, differentiating by the type of metastasis. Methodology This is an observational single-center retrospective study. We reviewed 96 patients with a diagnosis of apparent early-stage endometrial cancer submitted to hysterectomy with salpingo-oophorectomy and SLN mapping from December 2015 to March 2022. Possible RFs for nodal metastasis were considered including clinical (age, BMI), and biochemical (CA125, CA 19.9, HE-4) parameters, anatomopathological characteristics (Myometral invasion – MI, Lymphovascular space invasion (LVSI), grade, histotype) and immunohistochemical findings (L1CAM, Ki67, estrogen receptor – ER, progesterone receptor- PR). Odds ratios(ORs) were calculated, and then RFs were confronted with logistic regression. Results Overall detection rate was 94.8%, 83.3% bilateral, and 11.5% unilateral. We removed 181 suspected SLNs. The preponderance of SLNs was found at the external iliac and interiliac stations (69%). 7 patients had macrometastases, 5 micrometastases, and 7 ITCs. Higher ER percentage resulted in a protective factor (PF) for lymph nodal metastasis. MI more than 50%, LVSI, and p53 positivity resulted in RFs for lymph nodal metastases. Histotype, age, and L1CAM showed a slight, not significant, correlation as possible RFs. The multivariate multinomial analysis didn’t find any statistically significant differences between the RFs and the type of metastasis.