Central Nervous System

Tumors of the central nervous system (CNS) differ in many ways from other tumors. First, these tumors are separated by an important natural barrier, the blood–brain barrier, with the aim of defending the CNS from external noxa but, in the case of cancer, limiting the efficacy of therapy. Second, the tumors of the CNS are malignant not only because of their biological behavior but because of their localization. Even very small and slow-growing tumors localized at important regions of the brain, like the brainstem, can have serious, deleterious, and fatal impact. Finally, tumors of the CNS have a very important impact on the quality of life of patients, with long-term disabling effects on everyday life. Therefore, tumors of the CNS require early diagnosis and a rapid multidisciplinary approach to choose optimal treatment. In these cases, special attention must be taken to select chemotherapies and targeting agents that do cross the blood–brain barrier.