2858 - The Impact of Lymphatic vs. Vascular Invasion on Clinical Outcomes in Early-Stage Endometrial Cancer
Presenter(s)
N. N. Tselepidakis1, E. Alzayadneh2, A. Mills2, M. Dibbern3, C. Landen4, R. Jin5, E. Janowski6, and K. Romano6; 1University of Virginia School of Medicine, Charlottesville, VA, 2University of Virginia, Department of Pathology, Charlottesville, VA, 3Emory University School of Medicine, Department of Pathology, Atlanta, GA, 4University of Virginia, Department of Obstetrics and Gynecology, Charlottesville, VA, 5University of Virginia, Department of Public Health Sciences, Division of Biostatistics, Charlottesville, VA, 6University of Virginia, Department of Radiation Oncology, Charlottesville, VA
Purpose/Objective(s): Lymphovascular space invasion (LVSI) is a key prognostic factor in endometrial cancer (EC), and a risk factor for which vaginal cuff brachytherapy (VBT) is frequently recommended. Pathologic LVSI is defined as invasion of tumor cells in lymphatic and/or blood vessels. While LVSI has recently been sub-categorized as “substantial” or “focal” due to significantly different clinical outcomes between groups, differential outcomes between lymphatic invasion (LI) or vascular invasion (VI) have not been explored. The purpose of this study is to evaluate if LI versus VI impacts clinical outcomes in patients with EC treated with VBT.
Materials/Methods: We conducted a retrospective review of patients with early-stage EC who underwent surgical staging and adjuvant VBT from 2012- 2023. Only patients with pathologically positive LVSI were included. Patient and treatment-related factors were recorded. Slides were evaluated by pathology including immunohistochemical stains to identify invasion in lymphatic spaces (D2-40+) and/or blood vessels (CD31+). Overall survival (OS) and progression-free survival (PFS) were represented using the Kaplan-Meier Curve and analyzed with the log-rank test. Local failure (LF), loco-regional failure (LRF), and distant metastases (DM) were evaluated using the competing risks cumulative incidence function and tested with Gray's test.
Results: 66 patients with stage I-II EC and +LVSI were identified at a single institution. The majority were FIGO stage I (95.5%), endometrioid histology (81.8%), and grade 1 (37.9%). On pathologic evaluation, 30 patients (45.5%) had LI alone, 23 patients (34.8%) had VI alone, and 13 patients (19.7%) had both. There was no significant difference in patient or tumor characteristics between those with LI or VI. The 3-year OS was 83.9% (95% CI 72.3-97.4). The 3-year PFS were 81.2% (95% CI 65.8-100), 72.9% (95% CI 52.8-100), and 76.2% (95% CI 52.1-100), amongst patients with LI, VI, or both, respectively. The 3-year LF rates were 8.7% (95% CI 1.4-24.7), 0%, and 0%, amongst patients with LI, VI, or both, respectively. There was no statistically significant difference in OS (p = 0.770), PFS (p = 0.95), LF (p = 0.299), LRF (p = 0.776), or DM (p = 0.824) amongst patients with LI, VI, or both. Multi-variable analyses were not conducted due to small sample size and limited number of events.
Conclusion: This single institution experience demonstrates no statistically significant differences in clinical outcomes when LVSI is sub-categorized by LI versus VI. Patients with LI alone may have a slightly higher risk of LF, although additional study is indicated to further investigate.