Ten-year survey of the intellectual deficits in children with acute lymphoblastic leukemia receiving chemoimmunotherapy.

Effects of chemoimmunotherapy, including cranial irradiation for central nervous system (CNS)-directed therapy, on children with acute lymphoblastic leukemia (ALL) were investigated. Fifty-five children with ALL in continuous complete remission (> 5 yr) and without evidence of current or past CNS diseases were evaluated in this retrospective study. Using standard measures of intelligence (IQ), we repeatedly (1-4 times/person; mean 2.1 times) evaluated IQ in the cohort of patients for the mean follow-up time of 9.7 yr, ranging from 5.4 to 15.8 yr. Fifty-five patients received the total number of 118 IQ testings and 40 patients received them more than twice. Patients were examined periodically at intervals of 1.4 to 10.0 yr (mean 4.8 yr) following diagnosis. Most of the published studies dealt with single IQ testing, and long-term follow-ups were not enough to assess the consequent IQ change. This report confirms and extends the previous findings: decreased IQ was related to age at diagnosis and irradiation (< 5 yr of age at diagnosis), irradiation-examination interval, and female sex. Further long-term follow-up study will be needed in these groups, since their IQs are still on the decline even after 10 yr of diagnosis.