Serial cranial computed-tomography scans in children with leukemia given two different forms of central nervous system therapy.

Cranial computed tomography (CT) was used to estimate the frequency and permanence of brain abnormalities in 108 consecutive children with acute lymphoblastic leukemia (ALL). Fifty-five patients received cranial irradiation (1,800 rad) with intrathecal methotrexate (RT group) and 53 patients received intravenous and intrathecal methotrexate without irradiation (IVIT group). Continuation treatment included sequential drug pairs for the RT group and periodic IVIT methotrexate for the other group. After 12 to 24 months of serial evaluation, five (9%) of the 55 patients in the RT group have had CT scan abnormalities, compared to 10 (19%) of 52 in the IVIT group (p = 0.171). Fourteen of the 15 patients with CT scan abnormalities had focal or diffuse white-matter hypodensity; these have reverted to normal in most cases, reflecting a dynamic process. While such CT findings are of concern and may be an early indicator of central nervous system toxicity, this remains to be proven. Therapy should not be altered on the basis of abnormal CT scans alone but in the context of the entire clinical situation.