Predictors of Overall Survival in Skull Base Chordoma

Objective: Skull base chordomas (SBCs) are rare skull base tumors that arise from notochordal remnants that typically follow a malignant pattern. They typically exhibit a slow developing, locally invasive nature, and have a poor prognosis. In this study, we aim to identify predicative factors of overall survival in patients with SBCs.

Methods: Medical records of patients who had primary resection of the SBCs at UPMC (2003–2020) were obtained through EMR databases and retrospectively reviewed. A Cox's univariate and multivariate analyses were used to determine predictive factors for OS. Kaplan–Meier survivorship curves were made to illustrate overall survival.

Results: Patient cohort demographics are demonstrated in [Table 1]. Ki67, brainstem compression, age at diagnosis, a preoperative KPS less than 80, and male sex were significant for predicting OS in Cox's univariate analysis (p < 0.05, [Table 2]). Cox's multivariate analysis included all variables with a p-value of <0.1 in univariate analysis and passed collinearity model fitting. Multivariate analysis showed that brainstem compression symptoms (HR = 13.99) and Ki67 (HR = 1.13) were statistically significant in predicting decreased overall survival (p < 0.05; [Fig. 1]). KM survival curves for level of Ki67 indicated high Ki67 (>7%) to be significantly predicative of decreased overall survival with high Ki67 predicting a median survival of 3.85 years and low Ki67 of 13.62 years (p < 0.0001; [Fig. 2A]). KM survival curves demonstrated that presence of brainstem compression symptoms was statistically significant for decreased overall survival (p < 0.0001) with a median survival of 5.65 years in patients with brainstem compression compared with 13.62 years without ([Fig. 2B]). A combination of high Ki67 and brainstem compression decreased median survival to 1.92 years and was statistically significant predicting decreased survival (p < 0.0001; [Fig. 2C]).

Conclusion: Presence of brainstem compression and high levels of nuclear protein Ki67 are independently significant predictive factors of decreased overall survival in patients with SBCs. This study was done on the largest cohort of SBCs patients known to date.

Fig. 1

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Table 1

Table 2

Publication History

Article published online:
15 February 2022