Clinical features and prognostic factors of extraskeletal osteosarcoma: A single-center retrospective study from China

Abstract

ObjectiveExtraskeletal osteosarcoma (EO) represents a rare manifesting variant of soft tissue sarcoma. This study aims to analyze clinical characteristics, natural course, and potential prognostic factors of EO based on literature review. MethodsClinical data of 12 patients with EO admitted to Department of Orthopedic Oncology Surgery of Beijing Ji Shui Tan Hospital from March 1995 to October 2019 were retrospectively analyzed, and clinical profile, therapies, and endpoints were summarized. ResultsEight patients were previously untreated, and four cases were recurrent. The median age on diagnosis was 53 years, and the mean follow-up time was 41.4 (range: 25 to 72) months. The lesions were located in the thigh of 5 patients, calf in 3, buttock in 2 and upper arm in 2. The lesions were located in the deep layer of fascia in 10 cases and in the superficial layer in 2, with a maximum diameter of 13 (4–19) cm on average, and Ennecking stage was IIB for 10 patients and III for 2. All patients underwent surgery, with a marginal resection in 8 cases, and wide resection in 4. Eight patients received chemotherapy, including two patients with neoadjuvant chemotherapy and 7 with postoperative adjuvant chemotherapy. Three patients with marginal resection had local recurrence and two of them underwent radical amputation. Five patients died from lung metastases, including two patients with pre-existing metastasis at presentation. ConclusionsEO is a rare high-grade soft tissue sarcoma. Age<50 years, no metastasis at presentation, superficial location of the tumor, and negative resection margin are favourable prognostic factors. For patients with positive margins, adjuvant radiotherapy is recommended to improve local control rates. High-risk patients may benefit from platinum-based chemotherapy regimens.