Does Lymph Node Assessment Change the Prognostic Significance of Extensive LVSI and p53 Mutation in Endometrial Cancer?

Abstract

While high-intermediate risk (HIR) early stage endometrial cancer patients achieve excellent outcomes with adjuvant vaginal brachytherapy (VBT), the recent PORTEC2 update suggested factors such as extensive lymphovascular space invasion (LVSI) and abnormal p53 expression predict for poorer outcomes and that these patients should be treated with external beam radiation therapy (EBRT), rather than VBT. Our study aims to determine if patients with these risk factors who undergo a lymph node assessment prior to receiving adjuvant therapy show similarly high recurrence rates.We identified 97 patients with FIGO 2009 stage IA grade 3, stage IB grade 1-2, and stage IIIC (with positive LN only but no other stage II or III factors) endometrial cancer who underwent surgical resection including lymph node assessment from 2009 to 2018 at our institution. We reviewed the LVSI status and extent, and the p53 status in these patients. Local failure (LF), regional failure (RF) distant metastasis (DM), and overall survival (OS) were compared using Kaplan-Meier.Median follow up was 52 months. The median OS was not reached. The 3-year cumulative incidence of failure were: 3.3% LF, 7.1% RF and 2.2% DF. Patients with any LVSI had poorer OS (P < 0.01, increased rates of LF (P < 0.02) and increased rates of RF (P < 0.04). Extent of LVSI also correlated with OS, LF, RF and DM, where patients with extensive LVSI has worse outcomes when compared with patients with limited LVSI (P = 0.04, P = 0.04, P = 0.04, P = 0.01, respectively). Abnormal p53 correlated with increased rates of LF (P < 0.02). Patients who had both abnormal p53 and any LVSI had worse OS (P > 0.0010), increased LF (P = 0.047) and RF (P < 0.01), compared to patients who had neither risk factor. 47% of the entire patient cohort and 50% of patients with extensive LVSI or abnormal p53 received radiation therapy. No patients who completed EBRT experienced in-field recurrences.Patients with HIR early stage endometrial cancer treated at our institution have had excellent outcomes. However, a small group of patients with unfavorable risk factors such as abnormal p53 expression and/or LVSI have worse outcomes, even with lymph node assessment, suggesting that these factors can aid in the selection of patients who may derive benefit from intensification of treatment. EBRT may be beneficial in this high risk population, as no patients who completed EBRT in our study had in field recurrences.C. Hui: None. M. Mendoza: None. R. Von Eyben: None. P. Hammer: None. B. Howitt: None. E.A. Kidd: Advisory Board; Varian Brachytherapy Advisory Board.