Sirolimus in advanced hemangioendothelioma.

10565 Background: Haemangioendothelioma (HE) is a very rare vascular tumor. The epithelioid variant is characterized by a specific t(1;3)(p36.3;q25) translocation, resulting in the WWTR1-CAMTA1 fusion product. We retrospectively reviewed patients with HE treated with sirolimus, an mTOR inhibitor, at our institution. Methods: We identified 12 patients (M/F: 4/8 – mean age: 46 years – epithelioid HE/ retiform HE: 10/2 – locally advanced/multifocal: 1/11 – pretreated: 6) with advanced HE who were treated with sirolimus, as a single agent, 5 mg/day, from 2005 on. They had evidence of progression in the 3 months before starting treatment. The daily dose of sirolimus was adjusted according to drug blood levels (range 10-20 ng/dl). Response was evaluated with CT/MRI/PET scans after 4-6 weeks of treatment, then every 3 months, by RECIST and Choi criteria. WWTR1 gene rearrangement was evaluated by FISH, and the histochemical expression of mTOR effectors, S6 and 4BP1, is ongoing. Results: 10 patients are evaluable ...