Prognostic Factors And Therapeutic Options For Epithelioid Hemangioendothelioma (Ehe): A Multicenter Analysis Of A Series Of Fifty-Seven Cases.

11062 Background: EHE is a rare vascular mesenchymal tumor for which there is currently no standard for treatment particularly for metastatic disease. EHE often present metastatic evolution but metastases are not a poor prognostic factor. The aim of this study was to improve knowledge of outcome of EHE patients and see the impact of active surveillance on outcome for metastatic EHE patients. Methods: Patients with EHE treated at three centers in France were included in this retrospective cohort. Univariate analysis of prognostic factors was performed using the Cox model. Survival was estimated using the Kaplan-Meier method and long rank analysis. Results: Fifty-seven patients with EHE were collected in this analysis: 27 (47%) women and 30 (53%) men, with a median age at diagnosis of 39 years (range, 12-83). At diagnosis, 17 (29.8%) patients had a localized tumor, while 40 (70.2%) patients had synchronous metastases. The most commonly affected organs were liver (29.8%), bones (14.0%), skin, lungs and soft tissues (10.5% each). For the 17 patients with localized EHE, the median distant recurrence-free survival after resection of primary was 64.6 months, 95% CI [29.4, NA], (median follow-up of 62.7 months, range, 12.5-234.8). For the 40 patients with metastatic EHE, the median progression-free survival (PFS) was 59.0 months, 95% CI [21.3, NA], (median follow-up of 121.1 months, range, 1.0-202.0). No prognostic factor was identified for localized EHE. For metastatic EHE, age was associated with progression (p = 0.019), and presence of pleural/ascites/pericarditis effusion adversely affected overall survival (OS) (p = 0.002). An initial “wait and see” attitude was proposed to 23 patients (57.5%) while 17 patients (42.5%) were treated at diagnosis with local or systemic treatment (monotherapy or combination of chemotherapy with anthracyclin, taxane, cyclophosphamide). OS were similar in both groups of patients, 174months and 121months for chemotherapy treated patients and active surveillance patients respectively (p = 0.56). Conclusions: Presence of effusion was a significant poor prognostic factor in metastatic EHE patients. Active surveillance could be proposed for asymptomatic patients without effusion but this strategy need to be confirmed in largest or prospective randomized trials.