Dedifferentiated chondrosarcoma: A survival analysis of 159 cases from the SEER database (2001‐2011)

Background and Objectives Dedifferentiated chondrosarcoma is a rare malignancy with reported 5‐year overall survival rates ranging from 7% to 24%. The purpose of this investigation is to determine the overall survival of dedifferentiated chondrosarcoma in a modern patient series and how it is impacted by patient demographics, tumor characteristics, and surgical treatment factors. Methods This is a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) database from 2001 to 2011. Kaplan Meier analyses were used for overall and disease‐specific survival. Univariable and multivariable cox regression models were used to identify prognostic factors. Results Five year overall‐ and disease‐specific survival was 18% (95% CI: 12‐26%) and 28% (95% CI: 18‐37%), respectively. Individuals with extremity tumors had a worse prognosis than individuals with a primary tumor in the chest wall or axial skeleton (HR 0.20, 95% CI: 0.07‐0.56; P = 0.002 and HR 0.60, 95% CI: 0.36‐0.99; P = 0.04, respectively). Patients with AJCC stage III or IV disease (HR 2.51, 95% CI: 1.50‐4.20; P = 0.001), tumors larger than 8 cm (HR 2.17, 95% CI: 1.11‐4.27; P = 0.046), metastatic disease at diagnosis (HR 3.25, 95% CI: 1.98‐5.33; P