Differences in clinical characteristics and tumor prognosis between primary and secondary conventional pelvic chondrosarcoma

Chondrosarcoma (CS) most commonly involves the pelvis. This study aimed to analyze differences in clinical characteristics and prognostic factors between primary and secondary conventional pelvic CS, and provide reference for clinical diagnosis and treatment.

Eighty patients (54 primary cases and 26 secondary cases) with pelvic CS were included in this retrospective study. The tumor site, Enneking stage, soft tissue mass, margin, initial tumor grade, incidence of local recurrence and distant metastasis were evaluated. Kaplan-Meier method was used to calculate the overall survival rate. X² test and log-rank test were used for univariate analysis, and Cox test was used in multivariate analysis.

The average age of patients with secondary CS was significantly younger than that of patients with primary CS (P < 0.001). The soft tissue mass of patients with secondary CS was significantly larger than that of patients with primary CS (P = 0.002). There was a significant difference in initial tumor pathologic grade between the two groups (P = 0.002). No statistically significant difference was observed in the local recurrence rate between the two groups. The median recurrence time of patients with primary CS after the first treatment was significantly shorter than that of patients with secondary CS (P < 0.001). The overall survival rate of patients with secondary CS was much higher than that of patients with primary CS (P = 0.003). Cox regression analysis showed that the initial tumor grade was an independent factor in the overall survival rate of patients with CS.

There were significant differences in age, soft tissue mass, initial tumor grade, and overall survival rate between the two groups. The overall survival rate of pelvic CS was related to the initial tumor grade of CS.