Epithelioid hemangioendothelioma of bone: A survival analysis of 50 cases from the SEER database (1992-2016).

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor that may arise in bone. The purpose of this investigation was to determine the clinicopathological features and outcomes of osseous EHE in a large patient series, and to assess whether survival is impacted by demographics, tumor characteristics, or treatment factors. This was a retrospective review of the Surveillance, Epidemiology and End Results (SEER) database from 1992 to 2016. Kaplan-Meier was used to estimate overall survival (OS) and disease-specific survival (DSS). A Cox regression model was used to identify prognostic factors. Fifty patients from 1992 to 2016 with a median age of 54.5 years (IQR, 37-67) were reviewed. For location, 46% (n = 23) of tumors arose from the appendicular skeleton while 38% (n = 19) occurred within the axial skeleton (overlapping EHE: 16%, n = 8). Of the cases with recorded treatment factors, 54.8% (n = 23) had surgery, 26% (n = 13) received radiation, 22% (n = 11) were treated with chemotherapy, and 26% (n = 13) had surgery plus radiation. The 5-year OS probability was 49.2% (95% CI, 23.6-70.6), and the 5-year DSS probability was 63.9% (95% CI, 33.0-83.5). No surgery (surgery: HR, 0.262; 95% CI, 0.07-0.9); p = 0.041) and age older than 50 years (HR, 4.117; 95% CI, 1.1-15.4; p = 0.035) were negative prognostic factors of disease-specific mortality after controlling for confounding variables. There was no association between disease-specific mortality and adjuvant or multimodal therapy. The prognosis of EHE of bone is less than favorable, and the 5-year DSS probability of 64% emphasizes the intermediate grade nature of this tumor subtype. Surgical treatment, when feasible, is associated with a better prognosis.