Reduced white matter and impaired neuropsychological function were seen 20-30 years later in childhood acute lymphoblastic leukemia and lymphoma survivors who received cranial radiotherapy.
Survivors treated with chemotherapy alone appeared to have milder impairments, with measures that were within one standard deviation of the measures seen in healthy controls, reported Ilse Schuitema of the University of Leiden and her associates.
They also found that a young age at the time of cranial radiotherapy and the radiation dosage were associated with poorer results on the MRI measure used to evaluate the white matter's microstructure. Decreases in this measure were associated with neuropsychological dysfunction. The study was published in the Sept. 20 issue of the Journal of Clinical Oncology (2013;31:3378-88).
The finding "warrants a recommendation to use CRT [cranial radiotherapy] only as a last resort," since chemotherapy is just as effective, based on survival and recurrence rates in patients with acute lymphoblastic leukemia (ALL). Further, indications of accelerated aging seen in survivors given cranial radiotherapy may support screening for early-onset dementia as well as recommending lifestyle modifications such as not smoking and getting regular physical exercise to slow the progress of dementia.
Ms. Schuitema of the department of clinical child and adolescent studies, faculty of social sciences at Leiden (the Netherlands) University, and her co-investigators, followed up with 93 survivors of ALL or lymphoma who had been treated between 1978 and 1990 with cranial radiotherapy or CNS-directed chemotherapy, and compared them with 49 healthy controls. The mean age of patients given chemotherapy only was 27 years and the mean age of those treated with radiotherapy was 31 years.
Testing included magnetic resonance diffusion tensor imaging and neuropsychological tests. Differences in fractional anisotropy on the MRI test were used to analyze white matter microstructure, and whole-brain, voxel-based analysis was performed.
Survivors treated with chemotherapy only had reductions in the MRI measure and neuropsychological performance, but the measures were no more than one standard deviation below the mean values of controls.
When compared with controls, survivors who had cranial radiotherapy had significant reductions in white matter integrity and lower neurocognitive function, with effects that included lower IQ, poorer visuomotor accuracy, and poorer work flow during sustained attention.
Further, there was a "steep decline," in the MRI measure within the frontal and parietal white matter, which "is a strong indication of accelerated aging" the researchers wrote. Some of the anatomical findings among those treated with CRT were similar to those found in people with Alzheimer's disease, suggesting that "the irradiated survivors could be at increased risk of developing early-onset dementia."
The study results highlight the importance of long-term follow-up of children who receive neurotoxic treatments and increase support "for the concept of accelerated aging after CRT implicates screening for early-onset dementia,"the researchers said.
The tests used in the study included the computerized Amsterdam Neuropsychological Tasks (ANT) program, used to assess executive functions, and the four subtest short-form of the Wechsler Adult Intelligence Scale Revised (WAIS-R III).
Ms. Schuitema's coauthors are from the University of Leiden; University Hospitals Leuven, Belgium; and Academic Medical Center, Amsterdam. The authors had no disclosures. The study was funded by grants, including one from the Dutch Cancer Society.