Approach to Pain in Patients with Central Nervous System Metastases

Central nervous system (CNS) metastasis is the condition by which a primary malignancy may spread to structures such as the brain, spinal cord, meninges, or cerebrospinal fluid. A multidisciplinary approach is necessary to care for patients with CNS metastases, with treatment of the oncologic condition to include radiation (external beam radiotherapy, brachytherapy, and stereotactic radiosurgery), systemic therapies (chemotherapy, immunotherapy, targeted therapy, and hormone therapy), intrathecal therapies, and surgery. The management of pain related to CNS metastases requires an understanding not only of the pathophysiology of the underlying malignant process but also of the pathophysiology of pain. Furthermore, clinician knowledge about the available pharmacologic agents and interventional modalities is necessary to provide a comprehensive approach to cancer pain management in patients with CNS metastases. The main foci of this chapter are to explain pain processing and to describe the various classes of pharmacologic agents used to treat the different types of pain, with emphasis on neuropathic-type pain, associated with CNS metastases. Interventional modalities to manage pain from CNS metastases are described in a separate chapter in this book.