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<0.001). The OS rate of patients with initial pCS was significantly higher than that of patients with second pCS (78.3 vs. 63.0%; P<0.001). Multivariable logistic regression analyses suggested that second pCS predicted higher all-cause mortality (hazard ratio, 1.72; 95% confidence interval, 1.31-2.26, P<0.001) compared with that in patients with initial pCS. Furthermore, there were no differences observed in the treatment benefits between the patients with initial and second pCS. In conclusion, second pCS was more frequently diagnosed in older patients compared with initial pCS. In addition, the prognosis of patients with second pCS was worse than that of patients with initial pCS, and the treatment is essentially the same for initial and second pCS.