Alveolar soft part sarcoma in children and young adults: A report of 69 cases

BackgroundAlveolar soft part sarcoma (ASPS) is a rare mesenchymal tumor characterized by ASPL-TFE3 translocation. Apart from complete surgical resection, there is no standard management strategy. ProcedureThe clinical data of 69 children and young adults less than 30years old with ASPS diagnosed from 1980-2014 were retrospectively collected from four major institutions. ResultsMedian age at diagnosis was 17years (range: 1.5-30). Forty-four (64%) were female. Median follow-up was 46months (range: 1-409). Most common primary sites were limbs (58%) and trunk (24%). ASPL-TFE3 translocation was present in all 26 patients tested. IRS postsurgical staging was I in 19 (28%), II in 7 (10%), III in 5 (7%), and IV in 38 (55%) patients. The 5-year event-free survival (EFS) and overall survival (OS) were 38% and 72%, respectively. The 5-year EFS and OS were 80% and 87%, respectively, for the 31 patients with localized tumors (IRS-I-II-III), and 7% and 61%, respectively, for the 38 patients with metastatic tumors (IRS-IV). Of 11 IRS-IV patients who received targeted therapy upfront, two had partial response, six had stable disease, and three had progressive disease. Median time to progression for IRS-IV patients was 12months for those treated with targeted therapy, 7months for cytotoxic chemotherapy (N=15), and 4months for observation only (N=6). ConclusionLocalized ASPS has a good prognosis after gross total resection. ASPS is resistant to cytotoxic chemotherapy. Although there are no curative therapies for patients with metastatic disease, prolonged disease stabilization may be achieved with targeted therapies.