A Preoperative Risk Classifier Predicts Tumor Progression in Patients with Cranial Base Chondrosarcoma
Eric Wang, Michael McDowell, Ezequiel Goldschmidt, Paul Gardner, Carl Snyderman, Andrew Venteicher
Introduction: Cranial base chondrosarcomas frequently involve critical neurovascular structures that make complete resection challenging. Predictors of tumor progression in the skull base as unknown.
Objective: To identify clinical features of cranial base chondrosarcoma that will predict tumor progression.
Methods: We performed a retrospective analysis at the University of Pittsburgh from 2004 to 2018. We recorded tumor locations and radiographic features. Our primary outcome was progression-free survival (PFS). Univariate and multivariate regression models were created. Of 41 patients treated for skull base chondrosarcoma, the mean age was 52 years, 60.5% were female, and mean follow-up was 55 months. For the entire cohort, the median PFS was 123 months.
Results: Older age was correlated with shorter PFS (p < 0.017). We performed univariate regression analysis of involved tumor locations and of radiographic parameters, and those parameters with a p-value of < 0.1 were fed into a Cox proportional hazards model. This revealed an independent association of both age (p < 0.018) and increasing number of arteries encased (p < 0.045) with PFS.
We next generated a grading scale based on both age and number of encased arteries (Figure 1a). This allowed us to risk stratify patients into a high risk (10% patients; median PFS 22 months), intermediate risk (66% patients; median PFS 97 months), and low risk groups (24% patients; none progressed) (Figure 4b).
Conclusions: In patients with skull base chondrosarcomas, age and artery encasement are two preoperative variables that predict tumor progression, which may help guide post-operative follow-up and adjuvant therapy.