LAUSR

Background: Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor that typically affects young patients. Because of the rarity of the disease, the standard treatment is not established. The aim of this study is to evaluate the clinical characteristics and treatment outcomes of pediatric ASPS. Method: A retrospective study was conducted on children and adolescents treated for ASPS at a single center between 2000 and 2018. Results: A total number of 11 patients were evaluated. Median age at diagnosis was 12.6 (range 3.8-16.3) years. Nine (82%) were female. The most common primary sites were limbs (64%). IRS postsurgical clinical group (IRS CG) was I in 2 (18%), III in 3 (27%), and IV in 6 (55%) patients. Of 9 patients with IRS CG III and IV who received chemotherapy, one had a complete response, two had a partial response, and six had progressive disease. One patient showed SD to sunitinib. The 5-year event-free survival (EFS) and overall survival (OS) rates were 31% and 88%, respectively. The 5-year EFS rate by primary site was 50% for the 7 patients with extremity and 0% for the 4 patients with head and neck (P-value = 0.001). The 5-year OS rate by the primary site was 100% for the 7 patients with extremity and 50% for the 4 patients with head and neck (P-value = 0.027). Conclusion: Localized ASPS has a good prognosis after total resection. If the primary site is head and neck, the prognosis is poor due to difficulty in surgical resection. Chemotherapy and radiation therapy have limitations in the cure for patients with metastatic disease. Further studies of ASPS need to achieve development in treatment. Citation Format: Se Na Kang, Jung Yoon Choi, Bo Kyung Kim, Hong Yul Ahn, Kyung Taek Hong, Hyoung Jin Kang, Han Soo Kim, Jung Eun Cheon, Sung Hye Park, Hee Young Shin. Alveolar soft part sarcoma in children and adolescents: A single-institute retrospective analysis [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A65.