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

Chondrosarcomas of the skull base are rare tumors most commonly treated surgically with or without adjuvant radiation therapy. Using the National Cancer Database (NCDB), we analyzed overall survival (OS), treatment modalities, and prognosticators.

The NCDB was queried for all cases of histologically confirmed skull base chondrosarcoma treated between 2004 and 2015, excluding patients with more than 1 malignant tumor, on palliative care, receiving unrelated concurrent treatments, or having less than 1 month of follow-up. The χ² test for categorical variables, Cox proportional hazards models, and Kaplan-Meier log-rank analysis were used to test associations with the use of adjuvant radiation, OS, and survival time.

A total of 498 patients with skull base chondrosarcoma were identified in the NCDB. Of them, 224 (45.0%) and 198 (39.8%) were treated with either surgery alone or surgery with adjuvant radiation therapy, respectively. Patients more likely to undergo surgery with adjuvant radiation had higher tumor grade (P = 0.008), later year of diagnosis (P = 0.002), positive surgical margins (P < 0.001), and treatment at an academic institution (P = 0.02). Patient, tumor, and socioeconomic factors associated with worse OS on multivariate analysis included the Charlson/Deyo Comorbidity Score ≥2 (P = 0.017), as well as clear cell (P = 0.02) and dedifferentiated (P = 0.006) histology. Age, tumor grade, tumor size, treatment modality, insurance status, facility type, and urban/rural population did not show a statistically significant impact on OS.

The mainstay of treatment for skull base chondrosarcoma is surgery, with consideration of adjuvant radiation. This study demonstrated worse overall survival associated with more frail patients and aggressive histology types. It is important to consider these factors when planning the clinical management of these patients.