Academic Fluency in Pediatric Brain Tumor Survivors Treated with Proton Beam Radiation Therapy versus Photon Radiation Therapy

Brain and central nervous system (CNS) tumors are the most common tumor type in children and adolescents, and are often treated with a combination of surgery, chemotherapy, and radiation therapy. Historically, most pediatric brain tumor patients have received photon radiation therapy (XRT). However, this treatment is associated with negative long-term neurocognitive and academic effects due to unavoidable irradiation of healthy brain tissue. In an effort to minimize radiation exposure to healthy tissue, proton beam radiation therapy (PBRT) was developed due to its ability to maximize radiation administered to the tumor and minimize radiation to normal tissue. This therapy is becoming an increasingly popular treatment for children, as scientists theorize that decreased irradiation of healthy brain tissue will correspond to relatively improved long-term cognitive and academic outcomes. However, very little research has explored outcomes in children treated with PBRT. The present study compared long-term cognitive (i.e., working memory, processing speed, vocabulary, attention, shifting, and fine motor) and academic (i.e., reading, math, and writing fluency) outcomes in pediatric brain tumor survivors treated with XRT versus PBRT, and evaluated the degree to which group differences in academic fluency are mediated by cognitive ability. Results revealed that PBRT patients outperformed XRT patients on multiple cognitive measures (vocabulary, processing speed, shifting, working memory) as well as all fluency measures (reading, writing, math fluency). In addition, vocabulary and processing speed fully mediated relations between group and all three fluency outcomes. Working memory also mediated relations between group and math fluency. Findings suggest that academic fluency interventions that are effective for typically developing children with learning disabilities may also ameliorate fluency difficulties in brain tumor survivors, although modifications would likely be needed due the significant processing speed difficulties that are unique to this population.