FRIDAY, Aug. 7, 2009 (HealthDay News) -- Even at low doses, radiation therapy for low-grade brain tumors can cause progressive decline in cognitive functioning, a new study reports.
Radiation is the most widely used treatment for such tumors, known as low-grade gliomas, the most common type of brain cancer.
Researchers in the Netherlands assessed cognitive abilities in 65 people an average of 12 years after treatment for low-grade gliomas. About half of them had received radiation. The assessment measured attention, executive functioning, verbal memory, working memory, psychomotor functioning and information processing speed.
Cognitive disability was found in 53 percent of those who'd had radiation treatment and 27 percent of those who'd received other treatments. In general, people in the radiation group had poorer attention, executive functioning and information-processing speed.
The "results indicate that radiotherapy [or radiation treatment] is associated with long-term cognitive deterioration, regardless of fraction dose," wrote Linda Douw, of the VU University Medical Center in Amsterdam, and her colleagues. "All surviving patients who had radiotherapy are at risk of developing attentional problems," not just survivors who received a high-level dose of radiation, according to the researchers.
Careful consideration should be given to the use of radiation in people with low-grade gliomas, the researchers said. They suggested that deferring treatment might be the most beneficial approach in terms of cognitive status and quality of life.
The study appears online and in the September print issue of The Lancet Neurology.
In an accompanying editorial, U.S. experts noted there have been substantial improvements in radiation techniques since people in the study were treated. Therefore, it's not possible to use the study's findings to make firm generalizations about the risks of modern radiation, wrote Paul Brown and Jane Cerhan of the Mayo Clinic.
They said that more studies are needed to assess the effects of current radiation techniques on cognitive functioning in people with low-grade gliomas.
The American Brain Tumor Association has more about the effects of radiation therapy.