Absence of prognostic value of lymphovascular space invasion in patients with endometrial cancer and negative sentinel lymph nodes.

OBJECTIVE: To evaluate if the prognostic value of lymphovascular space invasion (LVSI) is different in endometrial cancer patients with negative lymph nodes following sentinel lymph node (SLN) mapping or lymph node dissection (LND) as staging procedure. MATERIAL AND METHODS: A retrospective study of 510 patients diagnosed with endometrial carcinoma in our institution between 2007 and 2014. We excluded patients that were diagnosed with positive nodes (Stage IIIc). We compared patients' characteristics and survival outcomes as function of their LVSI status (positive LVSI vs negative LVSI subgroups) in each cohort separately. RESULTS: 413 patients met the inclusion criteria, out of whom 239 underwent SLN and 174 patients underwent LND only. In the SLN group, life table analysis showed 5-year OS and PFS of 80% and 72% in patients with LVSI compared to 96%, and 93% without LVSI. Same trend was observed among patients with LND with 5-year OS and PFS of 74% and 64% in patients with LVSI compared to 97%, and 90% without LVSI. On multivariable analysis, adjusted for age, FIGO stage, grade and maximal tumor size, the favorable survival of negative LVSI remained only in the LND cohort (SLN cohort: HR 1.2, CI [0.3-4.0], P = 0.8 and HR 1.7, CI [0.7-4.3], p = 0.2 for OS and PFS, respectively; LND cohort: HR 3.1, CI [1.4-6.5], p < 0.001 and HR 2.5, CI [1.2-4.9], p = 0.01 for OS and PFS, respectively). CONCLUSIONS: The prognostic value of LVSI disappears when patients undergo staging with SLN and are found to have negative nodes in contrast to those who have undergone LND. Future studies should confirm our observation on patients with negative sentinel nodes, and plan on tailoring adjuvant treatment to this specific subgroup.