Treatment practices and response in kaposiform hemangioendothelioma: A multicenter cohort study.

Abstract

Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumors in children historically associated with significant morbidity and mortality. This study was conducted to determine first-line therapy in the absence of available prospective clinical trials. Patients from 17 institutions diagnosed with KHE/TA between 2005 and 2020 with more than 6months of follow-up were included. Response rates to sirolimus and vincristine were compared at 3 and 6months. Durability of response and response to other treatment modalities were also evaluated. Of 159 unique KHE/TA subjects, Kasabach-Merritt phenomenon (KMP) was present in 64 (40.3%), and only two patients were deceased (1.3%). Over 60% (n=96) demonstrated treatment response at 3months, and more than 70% (n=114) by 6months (no significant difference across groups). The vincristine group had higher radiologic response at 3months compared to sirolimus (72.7% vs. 20%, p=.03), but there were no differences between these groups at 6months. There were no differences in rates of recurrent or progressive disease between vincristine and sirolimus. In this large, multicenter cohort of 159 patients with KHE/TA, rates of KMP were consistent with historical literature, but the mortality rate (1.3%) was much lower. Overall treatment response rates were high (>70%), and there was no significant difference in treatment response or durability of disease comparing sirolimus to vincristine. Our results support individualized treatment decision plans depending on clinical scenario and patient/physician preferences. Response criteria and response rates reported here will be useful for guiding future treatment protocols for vascular tumors.