This chapter aims to review common neuropsychiatric manifestations seen in patients with cancer, as well as principles of assessment and management that can be used in treating these patients. It will start with a discussion of primary brain tumors and explore their epidemiology, classification, pathophysiology, and clinical presentation. It will then examine neuropsychiatric manifestations of cancers that metastasize to the brain, and rare complications including leptomeningeal carcinomatoses. Subsequently, paraneoplastic syndromes, which are infrequent but challenging causes of neuropsychiatric symptoms in cancer patients, will be discussed. This will be followed by a review of commonly encountered neuropsychiatric symptoms in cancer patients. Additionally, the neuropsychiatric side effects of cancer treatments, including radiation therapy, chemotherapy, antiepileptic drugs, and steroids will be considered. Finally, the chapter will address the treatment of neuropsychiatric symptoms in cancer patients using pharmacologic and behavioral approaches.
Cancer and its treatment may affect the brain both directly and indirectly with profound neuropsychiatric consequences. There are nearly 700,000 individuals in the United States with a brain tumor, which are categorized as primary when they originate in the brain, or metastatic when they originate from other parts of the body. Approximately 138,000 of all brain tumors are malignant, constituting brain cancer. Central and peripheral nervous system cancers represent a smaller fraction (approximately 1.4%) of all new brain cancer diagnoses. On the other hand, metastatic brain cancers are more prevalent, since approximately 20–40% of all cancers metastasize to the brain.
Neuropsychiatric and cognitive disorders are extremely common in individuals with brain tumors. More than 50% of brain tumor patients meet diagnosable criteria for a psychiatric disorder. Similarly, cognitive dysfunction is present in over 70% of patients with central nervous system (CNS) malignancies. The manifestations of these disorders are determined by two main factors: (a) the location and affected neurological circuits; and (b) the growth and infiltration pattern of the particular tumor and associated edema.1 It is important to appreciate that manifestations of cognitive dysfunction and psychiatric disorders may vary through the cancer course, in accordance with tumor localization and specific treatments received.
Primary brain tumors are a relatively uncommon form of cancer, with high mortality rates.2 As a group, these tumors are heterogeneous. Primary brain tumors may arise from the parenchyma or surrounding structures, such as the meninges, neuroepithelial tissues, pituitary, cranial nerves, and germ cells.
There is a 0.6% lifetime risk of being diagnosed with a brain or other nervous system cancer.3 The overall incidence of primary brain tumors is 10.82 per 100,000 person-years.4 In the United States, there were an estimated 23,380 new cases diagnosed in 2014 accounting for 1.4% of all new cases of cancer.3 In the same year primary brain tumors led to 14,320 deaths, accounting for 2.4% of all cancer-related deaths.3