The impact of Substantial LYMphovascular space invasion on sentinel lymph nodes status and recurrence in Endometrial Cancer patients: SLYM-EC a multicenter retrospective study.

Introduction
To evaluate the prognostic impact of substantial lymph vascular space invasion (LVSI) on the sentinel lymph node involvement and recurrence rate of patients with apparent uterine-confined endometrial cancer.Materials And Methods
We enrolled consecutive patients with apparent confined endometrial cancer who underwent surgical staging with sentinel node mapping from 14 European reference centers. LVSI was analyzed semi-quantitatively, according to a 3-tiered scoring system classified as absent, focal, and substantial.Results
Among 2352 eligible patients, 1980 were included in the analysis. Upon final pathology 226 patients (11.4 %) had SLNs involvement. LVSI was diagnosed focal in 152 patients (7.7 %), whereas 357 patients (18.0 %) showed substantial LVSI. Focal or substantial LVSI rate were significantly higher in patients with positive SLNs when compared to patients without SLNs involvement (p < 0.0001). On overall patient-based analysis, the sensitivity, specificity, positive predictive value, and negative predictive value of LVSI for sentinel lymph node metastases were 73 %, 80 %, 32 %, and 96 %, respectively. The 3-year multivariate analysis of recurrence-free survival showed that only the presence of substantial LVSI, and grade 3 disease were associated with relapse. Neither positive sentinel lymph node, deep myometrial infiltration, nor age at surgery were statistically significant.Conclusions
In patients having undergone sentinel node biopsy, positive LVSI demonstrated moderate sensitivity and reasonable specificity in detecting SLN involvement. LVSI positivity does not correlate with nodal involvement. The presence of substantial LVSI remains a strong independent risk factor for recurrence, indicating a role for potential hematogenous dissemination in patients with early-stage disease.