ABNORMAL CT SCANS OF BRAIN IN ASYMPTOMATIC CHILDREN WITH ACUTE LYMPHOCYTIC-LEUKEMIA AFTER PROPHYLACTIC TREATMENT OF CENTRAL NERVOUS-SYSTEM WITH RADIATION AND INTRATHECAL CHEMOTHERAPY

Thirty-two asymptomatic patients with acute lymphocytic leukemia, who had received prophylactic cranial radiation (2400 rads) and either intrathecal methotrexate or cytosine arabinoside were studied by computed tomography of the brain 19 to 67 months after initiation of prophylaxis. Seventeen of 32 (53 per cent) had one or more abnormal findings. Dilatation of the ventricles (eight patients) and widening of the subarachnoid spaces (nine patients) were equally distributed among patients in both intrathecal-chemotherapy groups. Areas of decreased attenuation coefficient (hypodense, abnormally radiolucent regions) (four patients) and intracerebral calcification (one patient) — lesions previously described in methotrexate leukoencephalopathy —were found only in those who had received intrathecal methotrexate. Mild Central-nervous-system dysfunction was detected in seven patients but did not correlate with the presence of tomographic abnormalities. Nevertheless, these tomographic findings may represent preclinical lesions. The unexpectedly high prevalence of such abnormalities contrasts with the essentially normal tomographic findings in a control group with acute lymphocytic leukemia who received no Central-nervous-system prophylaxis. These results suggest that alternative approaches to such prophylaxis be considered. (N Engl J Med 298:815–818, 1978) THE central nervous system appears to serve as a sanctuary for leukemic cells in that systemic treatment, though effective in preventing bone-marrow relapse, often fails to prevent meningeal leukemia. This circumstance appears to be due to inability of systemically administered chemotherapy to penetrate the central nervous system effectively. The institution of specific Central-nervous-system prophylaxis at a time when the number of leukemia cells in that location is presumably low has greatly reduced occurrence of overt meningeal leukemia, thus increasing survival of children with acute lymphocytic leukemia.12 Although the long-term sequelae of Central-nervous-system prophylaxis have not been well defined, the therapeutic. © 1978, Massachusetts Medical Society. All rights reserved.