Epidemiology of primary malignant non-osseous spinal tumors in the United States.

BACKGROUND CONTEXT:Primary malignant non-osseous spinal tumors are relatively rare and this has led to a paucity of studies specifically examining the epidemiology of malignant spinal tumors. PURPOSE:To provide an updated and more comprehensive study examining the epidemiology and relative survival of these rare tumors. STUDY DESIGN/SETTING:Data was retrospectively acquired from the Central Brain Tumor Registry of the United States (CBTRUS). PATIENT SAMPLE:Primary malignant non-osseous spinal tumor cases diagnosed between 2000 and 2017 in the United States. OUTCOME MEASURES:Incidence rates (IRs), relative survival rates, and hazard ratios (HR) were measured. METHODS:IRs were calculated only for histologically-confirmed cases between 2000 and 2017. Relative survival estimates were calculated from survival information on malignant spinal tumors between 2001 and 2016 for death from any cause. Multivariable Cox proportional hazards regression models were constructed to control for age, sex, race, and ethnicity. RESULTS:From 2000 to 2017, approximately 587 new cases of malignant non-osseous spinal tumors were diagnosed every year in the United States. The overall IR was 0.178 per 100,000 persons. Ependymomas were the most commonly diagnosed tumor in all age groups. The 10-year relative survival rates were 94.1%, 62.1%, 62.0%, and 13.3% for ependymomas, lymphomas, diffuse astrocytomas, and high-grade astrocytomas, respectively. Females have a significantly lower risk of death as compared with males for ependymomas (HR: 0.74, p<.001) and diffuse astrocytomas (HR: 0.70, p=.005). African-Americans have a significantly higher risk of death compared with Caucasians when diagnosed with ependymomas (HR: 1.52, p=.009) or lymphomas (HR: 1.55, p=.009). CONCLUSION:Primary malignant non-osseous spinal tumors are primarily diagnosed in adulthood or late adulthood. Ependymal tumors are the most commonly diagnosed primary malignant non-osseous spinal tumors and have the highest 10-year relative survival rates. High-grade astrocytomas are rare and portend the worst prognosis.