Background and Objectives: 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. Methods: Patients from 17 institutions diagnosed with KHE/TA between 2005-2020 with > 6 months follow-up were included. Response rates to sirolimus and vincristine were compared at 3 and 6 months. Durability of response and response to other treatment modalities were also evaluated. Results: Of 159 unique KHE/TA subjects, Kasabach-Merritt phenomenon (KMP) was present in 64 (40.3%) and only 2 patients were deceased (1.3%). Over 60% (n=96) demonstrated treatment response at 3 months and >70% (n=114) by 6 months (no significant difference across groups). The vincristine group had higher radiologic response at 3 months compared to sirolimus (72.7% vs 20%, p=0.03) but there was no differences between these groups at 6 months. There were no differences in rates of recurrent or progressive disease between vincristine and sirolimus. Conclusions: 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 were 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.

Background Infantile hemangioma (IH) is the most common benign tumor of infancy. For children with IH who require treatment, propranolol and other beta blockers have been shown to be safe and effective. Although consensus guidelines for propranolol have been published, anecdotal experience suggests that there remain variations in management. This study was performed to document these variations amongst providers and to identify areas for future research. Methods We conducted an internet-based survey of clinicians who treat patients with IH. Characteristics of respondents were collected. Hypothetical cases and management scenarios were presented and respondents were ask to comment on dosing, monitoring, frequency of follow-up, duration of therapy, whether to taper or abruptly discontinue mediation, and which patients should get additional evaluation. Results Twenty-nine respondents participated in the survey: pediatric hematologists/oncologists (n= 15), pediatric cardiologists (n= 10), dermatologists (n = 2), an ophthalmologist (n = 1), and a neonatologist (n = 1). Most respondents use generic propranolol in infants with growing IH of the head and neck, with a goal dose of 2 mg/kg/day, until approximately one year of age. A variety of management strategies were documented including which patients should be treated, optimal dose and duration of therapy, how patients should be monitored, which patients should get additional work up, how propranolol should best be discontinued, and how often to see patients in follow-up. Conclusions This study demonstrates wide practice variations in managing patients with infantile hemangioma. Further research is indicated to address these variations and develop additional/updated evidence-based guidelines.