RT Journal Article SR Electronic T1 Lympho-vascular space invasion is strongly associated with lymph node metastases and decreased survival in endometrioid endometrial cancer: a swedish gynecologic cancer group (SweGCG) study JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A6 OP A6 DO 10.1136/ijgc-2019-ESGO.6 VO 29 IS Suppl 4 A1 Stålberg, K A1 Bjurberg, M A1 Borgfeldt, C A1 Carlson, J A1 Dahm Kähler, P A1 Flöter-Rådestad, A A1 Hellman, K A1 Hjerpe, E A1 Holmberg, E A1 Kjølhede, P A1 Marcickiewicz, J A1 Rosenberg, P A1 Tholander, B A1 Åvall-Lundqvist, E A1 Högberg, T YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A6.1.abstract AB Introduction/Background The aim of this study was to evaluate the impact of lymphovascular space invasion (LVSI) on the risk of lymph node metastases and survival in endometrioid endometrial adenocarcinoma.Methodology This is a retrospective cohort study based on prospectively recorded data. Patients with endometrioid adenocarcinoma registered in the Swedish Quality Registry for Gynecologic Cancer 2010–2017 with FIGO stages I-III and verified nodal status were identified (n=1587). LVSI together with DNA ploidy, FIGO grade, myometrial invasion and age, were included in multivariable regression analyses with lymph node metastases as the dependent variable. Associations between the risk factors and overall and relative survival were included in multivariable models. Estimates of risk ratios (RR), hazard ratios (HR), excess mortality rate ratios (EMR), and 95% confidence intervals (95% CI) were calculated.Results The presence of LVSI presented the strongest association with lymph node metastases (RR=5.46, CI 3.69–8.07, p<0.001) followed by deep myometrial invasion (RR=1.64, CI 1.13–2.37, p=0.008). In the multivariable survival analyses, LVSI (EMR=7.69, CI 2.03–29.10, p=0.003) and non-diploidy (EMR=3.23, CI 1.25–8.41, p=0.016) were associated with decreased relative survival. In sub-analyses including only patients with complete para-aortic and pelvic lymphadenectomy and negative lymph nodes (n=404), only LVSI (HR=2.50, CI 1.05–5.98, p=0.039) was associated with a worsened overall survival.Conclusion This large nationwide study identified LVSI as the strongest independent risk factor for lymph node metastases and decreased survival in patients with endometrioid adenocarcinomas. Moreover, decreased overall survival was also seen in patients with LVSI-positive tumors and negative lymph nodes, indicating that hematogenous dissemination might also be important.Disclosure Nothing to disclose.