Epidemiological and clinicopathologic characteristics, and prognostic factors of patients with Extra-skeletal Osteosarcoma

Abstract

Abstract The aim of this study was to investigate the epidemiological characteristics and prognostic factors of Extra-skeletal Osteosarcoma (ESOS) and to establish and validate a prognostic model. The baseline information and survival outcome of patients was illustrated according to different primary tumor sites. The independent prognostic factors for ESOS were analyzed using univariate and multivariate Cox regression analysis. A nomogram was constructed using these prognostic factors to predict the prognostic survival of patients. Kaplan-Meier method was performed to estimate survival and both log-rank test and Wilcoxon-Breslow-Gehan test were used to compare the survival. A total of 4567 patients with osteosarcoma who met the inclusion criteria were enrolled, including 4317 patients with osteosarcoma of bone and joint origin and 250 patients with ESOS. The 1-, 3-, and 5-year tumor-specific survival rates for ESOS were lower than those for skeletal osteosarcoma. Multivariate Cox analysis showed that older age at diagnosis, distant staging, and presence of bone metastases were independent risk factors affecting patient prognosis, and surgery of the primary site was an independent factor suggesting a better survival outcome. A nomogram was created based on these factors to predict OS at 1, 3 and 5 years in patients with ESOS. An internally validated nomogram consistency index showed satisfactory results between predictions. Primary focus surgery is an important factor in improving survival outcomes in patients with ESOS. The nomogram for predicting the prognostic of patients with ESOS was proved to be favorable accuracy and reliability. Such prognostic nomogram may assist clinicians optimize clinical treatment.