Efficacy of bevacizumab and temozolomide in locally advanced and metastatic hemangiopericytoma (HPC) and malignant solitary fibrous tumor (SFT).

Abstract

e22535 Background: Patients with locally advanced, recurrent or metastatic HPC/SFT are often treated with a combination of BEV/TEM based on the clinical efficacy reported in a cases series of 14 patients (Park MS, et al. Cancer 2011). BEV is costly and this regimen should ideally be supported with further data. Given the rarity of HPC/SFT, large trials are not feasible. We report the efficacy of this regimen based on population-based analysis. Methods: This was a population-based retrospective, multi-centre analysis using patient data from the BC Cancer Agency, a government funded, integrated care organization which delivers cancer drug therapy through a network of cancer centres in the province of British Columbia, Canada. Cases from June 2006 through October 2016 were identified from the provincial registry and systemic therapy drug database for patients receiving at least one treatment of BEV/TEM for histologically diagnosed locally advanced, recurrent or metastatic HPC/SFT. The primary outcome was overall response rate (ORR) based on changes of lesion size in computerized tomography scan and clinical assessment through chart review. Secondary outcomes included time to response, progression free survival (PFS) and overall survival (OS), estimated using the Kaplan-Meir method. Results: Fourteen patients were identified: median age 59 (range 44-70), male 78.6%. Diagnoses were HPC 4 (28.6%) and SFT 10 (71.4%), with metastatic disease in 10 (72.7%) patients. Primary sites were: meninges 4 (28.6%), lung/pleura 2 (14.3%), pelvis 3 (21.4%), abdominal wall 2 (14.3%), gluteal regional 1 (7.1%), others 2 (14.3%). Eleven (78.6%) patients had no prior drug therapy. The median follow-up was 15.5 months, with median treatment of 4 months. ORR was 21.4% with median time to response of 4 months (3 [21.4%] partial response, 10 [71.4%] stable disease, 1 [7.1%] progressive disease). Median PFS, 6-month PFS and OS were 17 months, 65.0%, and 45 months, respectively. Conclusions: Efficacy of BEV/TEM in HPC/SFT appeared to be similar to that previously reported. PFS and OS were longer in our patients, probably reflected by having most patients with SFT and less heavily pretreated.