Radiotherapy after gross-total resection and subtotal resection of spinal chordoma: a SEER database analysis of overall survival outcomes.

OBJECTIVE: Chordomas are most frequently found in the sacrum, vertebral column, and skull base. Achieving gross-total resection (GTR) has been shown to optimize overall survival (OS); however, the efficacy of radiotherapy (RT) for patients with GTR is currently not well understood. Given that RT may negatively impact patient quality of life, the aim of this study was to evaluate the utility of RT for improving OS in patients who have undergone GTR of spinal chordoma through analysis of the national Surveillance, Epidemiology, and End Results (SEER) database. METHODS: The SEER database (1975-2018) was queried for all adult patients (≥ 21 years) who underwent GTR for spinal chordoma. Bivariate analysis was conducted using chi-square testing for categorical variables, and the log-rank test was performed to find the associations of clinical variables with OS. Cox proportional hazards models were generated for multivariate analyses of the associations among clinical variables and OS. RESULTS: A total of 263 spinal chordomas that underwent GTR were identified. The mean age of all included patients was 58.72 years, and 63.9% of patients were male. In addition, 0.4% had dedifferentiated histology. The mean follow-up was 75.54 months. Of all patients, 152 (57.8%) received no RT and 111 (42.2%) received RT. Patients with sacral tumor location (80.9% vs 51.4%, p < 0.001) were more likely not to undergo RT when compared to patients with vertebral column location. In multivariate analysis, only age ≥ 65 years was associated with poorer OS (HR 3.16, CI 1.54-5.61, p < 0.001). RT did not have a statistically significant association with OS. CONCLUSIONS: RT after GTR of chordoma did not improve OS among SEER chordoma patients to a value that achieved statistical significance. Additional multicenter prospective studies are needed to determine the true efficacy of RT after GTR of spinal chordoma.