Neurooncology is the subspecialty of neurology that deals with the neurologic complications of cancer. Neurologic symptoms may arise from primary malignancies of the brain, and for that reason, one focus of neurooncology is the management of gliomas and other primary tumors of the CNS. A second, equally important focus is the diagnosis and management of neurologic complications of systemic cancer and its treatment which is the core of this book. This second focus extends far beyond brain metastases, a problem that is already ten times more common than malignant gliomas [3, 7].

The first step in managing a neurologic complication of cancer is the correct identification of the underlying problem. A cancer patient with a change in gait may have loss of proprioception from prior chemotherapy, disease within the CNS, or severe pain that limits function. Correct diagnosis and treatment of the patient’s complaint is contingent upon the same principles of neurology that apply to the non-cancer population. A careful history and detailed exam localizes the deficit in the nervous system to a focal, multifocal, or diffuse process. From that localization, a neurologic differential diagnosis can be developed that is based on specialized knowledge of the characteristic propensities of each cancer, the off-target effects of a wide array of conventional cytotoxic, novel small molecule and biologic therapeutics, and the complications of radiotherapy and surgical treatments. The most common neurologic complications of cancer and their association with different malignancies and treatment are provided in Table 1.2.