Chondrosarcoma of the Osseous Spine Treated by Surgery With or Without Radiotherapy A Propensity Score Matched and Grade/Stage-stratified Study

Study Design: This was a longitudinal cohort study. Objective: The main objective of this study was to investigate the outcomes of surgery with or without radiotherapy during treatment of patients with chondrosarcoma of the osseous spine. Summary of Background Data: Chondrosarcoma is a primary spinal malignant tumor; chemotherapy and radiotherapy (RT) are generally unsuccessful, and thus, the main treatment of choice is complete en bloc resection. However, even with complete resection, these patients still have a significant rate of recurrence, morbidity, and mortality. Although there have been reports that the addition of RT to surgery may lead to increased survival and better cancer control, the evidence of the efficacy of RT remains controversial. Materials and Methods: Patients diagnosed with chondrosarcoma who are then treated by surgery alone or surgery+RT were identified and extracted from the SEER (Surveillance, Epidemiology, and End Results) database (1973-2013). Propensity score matched (PSM) analysis was performed to balance patient characteristics between surgery alone and surgery+RT groups. Patients with a different grade and stage were stratified and analyzed. Results: A total of 778 patients with chondrosarcoma of the osseous spine treated by surgery alone or surgery+RT were extracted from the SEER database. Before PSM, the unadjusted Kaplan-Meier curve and bivariable Cox proportional hazard regression models showed that the surgery alone group had higher chondrosarcoma cancer-specific survival and overall survival than the surgery+RT group (both P<0.001), while the difference was attenuated after PSM. Stratified analysis found that RT was worse for low-grade chondrosarcoma patients and had a better trend for high-grade chondrosarcoma patients. Conclusions: The results of our present study suggest that low-grade chondrosarcoma of the osseous spine is resistant to RT, while high-grade chondrosarcoma patients had a better trend with RT.