Treatment-related white matter changes in cancer patients.

Forty cancer patients with bilateral diffuse cerebral white matter hypodensities on computerized tomography (CT) scan were reviewed. Brain irradiation and/or chemotherapy were considered responsible for the CT abnormalities in all patients but one, whose changes were presumably due to demyelination related to the aging process. Among these 39 patients, 7 had clinical symptoms of leukoencephalopathy. Two patients had acute transient leukoencephalopathy, and one of them experienced permanent neurologic changes after continuing treatment. Six additional patients had delayed leukoencephalopathy. The interval between whole-brain irradiation (WBXRT) alone and the CT detection of white matter hypodensities was almost always longer than 1 year. This interval was shortened to less than 1 year in a significant number of patients when WBXRT was followed by various chemotherapeutic protocols. More importantly, there was an increased incidence of clinical leukoencephalopathy. A higher incidence of clinical leukoencephalopathy in patients receiving intracarotid chemotherapy in the treatment of brain tumors and in patients receiving combination chemotherapy for central nervous system relapse of adult leukemia suggests a need for further investigation.