Determinants of Survival in Skull Base Osteosarcoma: A National Cancer Database Study

OBJECTIVE: Skull base osteosarcoma is a rare and aggressive tumor that is most commonly treated with primary surgical resection and adjuvant chemoradiation. Using the National Cancer Database, we analyzed demographic and clinical prognosticators for overall survival (OS). METHODS: The National Cancer Database was queried for cases of histologically confirmed skull base osteosarcoma treated between 2004 and 2015, excluding patients receiving palliation or having <1 month of follow-up. A total of 314 patients treated with surgery alone (n = 82), surgery with adjuvant radiotherapy (n = 35), surgery with chemotherapy (n = 114), or trimodality therapy (n [ 56) were identified. The chi(2) test for categorical variables, Cox proportional hazards models, and Kaplan-Meier log-rank analysis were used to test associations with treatment, OS, and survival time. RESULTS: None of the studied demographic characteristics (age, sex, race, overall health) and socioeconomic factors (income and average regional education) were associated with OS (none P < 0.05). Treatment modalities also did not show a significant association with OS (none P < 0.05). Certain tumor characteristics showed an association with OS, with fibroblastic and Paget histologic subtypes (each P = 0.003), poorly differentiated tumor grade (P = 0.03), and tumor size >5 cm (P = 0.045) associated with poorer OS. CONCLUSIONS: Tumor histologic subtype, advanced tumor grade, and greater tumor size are predictors of worse OS in skull base osteosarcoma. No significant differences in OS were identified based on treatment modality, which warrants further investigation.