Prognosis and treatment differences between initial and second primary chondrosarcoma

Prognosis and treatment differences between initial and second primary chondrosarcoma (pCS) remain unknown. In the present study, patients with chondrosarcoma diagnosed between January 2004 and December 2015 were identified using the Surveillance Epidemiology and End Results database. Kaplan-Meier curves and log-rank tests were used to assess overall survival (OS) and cancer-specific survival. Univariable and multivariable Cox regression analyses were used to determine factors associated with all-cause mortality and cancer-specific mortality. In total, 1,655 eligible patients were included in the cohort of the present study, of which, 1,455 (87.9%) had initial pCS and 200 (12.1%) had second pCS. Patients with second pCS were more frequently diagnosed in the age range of 61-80 years compared with patients with initial pCS (52.5 vs. 43.1%; P