Incidence and survival rates and trends of skull Base chondrosarcoma: A Population-Based study

Introduction: Chondrosarcomas are extremely rare, locally invasive, and potentially mortal malignant cartilaginous tumors. In this study, we aimed to evaluate the incidence and survival rates and trends of skull base chondrosarcomas (SBC). Methods: Data from SBC patients between 1975 and 2017 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The age-adjusted incidence rates (AAR) were calculated for the overall cases and based on gender, age, race, and histology. Furthermore, the relative survival rates for one, three, and five years, and the rates stratified to the aforementioned selected variables were computed. Besides, we conducted a joint point regression analysis to calculate the annual percent change (APC) and its associated standard error (SE) for AAR and mortality. Results: The AAR rate of SBC was 0.019 per 100,000. Higher AAR rates were observed in patients who were in the 65-74-year-age-group, females, Caucasians, and had none mesenchymal subtype. The relative one-year, three-year and five-year-survival rates were 99.58 %, 93.67 %, and 89.10 %, respectively. Lower survival rates were noted in patients who were males, African Americans, and had a mesenchymal subtype. The trend analysis has shown a significant yearly increase (P < 0.001) in AAR of SBC (APC +/- SE = 0.0005 %+/- 0.0001), along with a significant yearly decline in mortality rates (APC +/- SE= -0.0202 %+/- 0.0029). Conclusion: Despite the increase in AAR over time, there has been a significant decline in mortality rates over time, which might have been due to the advancement of treatment modalities, improvement in diagnostic imaging, and modification in disease grading.