Epidemiology of Brain Tumors

Brain tumors can be classified as primary if they originate from intracranial elements, and secondary if they originate from another organ, as metastases. The global prevalence of central nervous system (CNS) neoplasms in 5 years is approximately 771,110 cases. Primary brain tumors represent 1.7% of all cancers and global incidence is 3.9 per 100,000 person-years for all central nervous system tumors; this incidence varies from age, gender, race and region, with higher frequency in Northern Europe, followed by Australia, United States and Canada. African-Americans show higher incidence of benign neoplasms, whereas Caucasian individuals show a higher rate of malignant neoplasms incidence. Central nervous system neoplasms are more frequent in women with meningiomas having the most significant difference. In primary brain tumors, meningiomas are the most frequent, representing 36.8% of all neoplasms; gliomas are the most common malignant type, representing 75% of the malignant central nervous system tumors, with a global incidence of 6 per 100,000 person-years. Global mortality of CNS neoplasms represents 2.71% of all deaths by cancer. The only risk factors confirmed for brain tumors are associated with ionizing radiation and hereditary cancer, such as phakomatosis syndromes (neurofibromatosis, tuberous sclerosis, von Hippel-Lindau’s, Gorlin’s, and Cowden’s) and other hereditary cancer syndromes (Lynch and Li-Fraumeni). Mortality tends to be higher in adults than in the child population. The 5-year survival rate for anaplastic astrocytoma is 30% and for glioblastoma (GB) is 5.6%, the 10-year survival rate for patients with glioblastoma is 0.71%. This chapter focuses on the epidemiological basis of brain tumors.