A review of long-term deficits in memory systems following radiotherapy for pediatric posterior fossa tumor.

• All memory systems are impaired in irradiated PFT survivors. • Memory systems are more mildly affected in non-irradiated PFT survivors. • Progress in radiotherapy has led to a reduction in long-term memory sequelae. • Further investigation of procedural and episodic memory is warranted. In recent years, progress in pediatric posterior fossa tumor (PFT) treatments has improved survival rates. However, the majority of survivors present neurocognitive sequelae that impact academic achievement. This review examines the literature from 2000 to 2020 on long-term outcomes in different memory systems for survivors of pediatric PFT, considering the impact of radiotherapy which is a well-known prognostic factor for global neurocognitive function. Of the 43 articles selected, 31 explored working memory, 19 episodic memory, 9 semantic memory and 2 procedural memory. Irradiated survivors had scores of <−2 standard deviation (SD) (n = 4 studies/25) or between −2SD and −1SD (n = 7 studies/25) for working memory; <−1SD for anterograde memory (n = 11/13), with a progressive decline in these two memory systems; <−1SD (n = 4/7) in semantic memory, and a deficit in perceptual-motor procedural learning (n = 1/1). Reducing craniospinal irradiation dose, limiting tumor bed boosts, and using proton therapy seem to have had a beneficial effect with better preservation of the memory score and a reduction in the decline over time. Non-irradiated survivors had memory systems that were less affected, with preservation of anterograde memory and maintenance of long-term stability. Memory deficits are a core feature in survivors of pediatric PFT, especially when treatment requires radiotherapy. To limit these effects, dose constraints for specific brain areas involved in memory should be defined. During long-term follow-up, specific attention is essential to identify these deficits in order to limit their impact on the quality of life. [ABSTRACT FROM AUTHOR]