ABSTRACT
Neurological complications in the cancer patient are an increasingly common problem. A simplistic explanation for this is that patients survive longer with their tumor and therefore develop more metastases at all sites, but it is also possible that the central nervous system (CNS) is a genuine ‘‘sanctuary site’’ for malignant cells from common solid tumors treated with systemic chemotherapy, just as it is in leukemia. A study of nearly 12,000 patients identified neurological complaints including altered mental state, headache, back pain, and leg weakness in 15% of patients with a variety of tumors (1) . In small cell lung cancer, the incidence of neurological disorder caused by the disease is 29% (2) , and a report from the Johns Hopkins Cancer Center identified neurological problems as the cause of 50% of unplanned hospital admissions, with changes in mental status, brain metastases and epidural spinal cord compression being the major problems (3) . The effects of metastatic disease on the nervous system can be severely disabling, with a catastrophic effect on the quality of life of a patient whose tumor may be eminently treatable. This is partly because the brain and spinal cord are enclosed in bone, and thus relatively smallvolume disease can cause disproportionately severe symptoms. In addition, the CNS lacks lymphatics, making removal of edema and biological detritus difficult and the capacity for regeneration of nervous tissue after damage is very limited.
