Epidemiologic and Survival Trends in Adult Primary Bone Tumors of the Spine.

BACKGROUND CONTEXT: Malignant primary spinal tumors are rare making it difficult to perform large studies comparing epidemiologic, survival, and treatment trends. We investigated the largest registry of primary bone tumors, the national cancer database (NCDB), to compare epidemiologic and survival trends among these tumors.

OBJECTIVE: To utilize the NCDB to describe current epidemiologic trends, treatment modalities, and overall survival rates in patients with chordomas, osteosarcomas, chondrosarcomas, and Ewing's sarcomas of the mobile spine. The secondary objective was to determine prognostic factors that impact overall survival rates.

STUDY DESIGN: Retrospective study PATIENT SAMPLE: A total of 1,011 patients with primary bone tumors of the spine (377 chordomas, 223 chondrosarcomas, 278 Ewing's sarcomas, 133 osteosarcomas) OUTCOME MEASURES: Five-year survival METHODS: We reviewed the records of 1,011 patients in the NCDB from 2004 through 2015 with histologically confirmed primary osteosarcoma, chondrosarcoma, Ewing's sarcoma, or chordoma of the spine. Demographic, clinical, and outcomes data were compiled and compared using Chi-squared tests and ANOVA. Long term survival was compared using the Kaplan-Meier (KM) method with statistical comparisons based on the log-rank test. Multivariate analysis was performed to determine survival determinants.

RESULTS: Surgical resection was the primary mode of treatment for chondrosarcoma (90%), chordoma (84%), and osteosarcoma (80%). The treatment for Ewing's sarcoma was multimodal involving chemotherapy, radiation therapy, and surgical resection. Five-year survival rates varied significantly with chordomas and chondrosarcomas having the greatest survival (70% and 69%), osteosarcomas having the worse survival (38%), and Ewing's having intermediate 5-year survival at 62% (overall log-rank p<0.0001). Multivariate analysis demonstrated significantly improved 5-year survival rates with younger age at diagnosis, private insurance status, lower comorbidity score, tumor grade, tumor size, surgical resection, and negative surgical margin. Radiation therapy only improved survival for Ewing's sarcoma.

DISCUSSION AND CONCLUSION: This study provides the most comprehensive description of the epidemiologic, treatment, and survival trends of primary bone tumors of the mobile spine. Secondly, patient and tumor characteristics associated with improved 5-year survival were identified utilizing a multivariate model.