QOL-30. LONG-TERM COGNITIVE FUNCTIONING AND TREATMENT-RELATED RISK FACTORS IN CHILDHOOD POSTERIOR FOSSA TUMOR SURVIVORS

Abstract

INTRODUCTION: Each constituent of posterior fossa tumor treatment can affect brain development tremendously. We investigated cognition in survivors of childhood posterior fossa tumor. METHOD: Neurocognitive assessments and T1-weighted MRI-images were acquired in 21 survivors (mean age at diagnosis 8.3 years; >2 years post-treatment, pilocytic astrocytoma (n=8), ependymoma (n=1) or medulloblastoma (n=12)); and 21 ageand gender-matched controls. A comprehensive neurocognitive test battery and questionnaires (WAIS-IV, RVDLT, AVLT, ANT, PPVT, COWAT, CFQ, BRIEF, STAI, BDI, PedsQL) were assessed. Based on anatomical scans, cerebellar tissue proportions were analyzed (as indication of atrophy). Scores were compared between patients and healthy controls. Interdependence of treatment-related risk factors (craniospinal radiation dose (0, 23.4, 35-36 and 40 Gy), posterior fossa boost, intraventricular MTX, (sub)total resection, postsurgical mutism, age at diagnosis and time since treatment) and cerebellar tissue was assessed, to predict cognitive scores by independent factors. RESULTS: First, IQ subscales, as well as visual memory and object naming were significantly lower in patients. Second, radiation dose, postsurgical mutism and time since treatment were found to be independent, and used for further analyses. Radiation dose was associated IQ and attentional reaction times, whereas the presence of postsurgical mutism was related to worse perceptual reasoning and emotional regulation. After corrections, only the link between RT and attentional reaction times remained significant. Finally, radiation dose and IV-MTX were associated with reduced current cerebellar tissue. DISCUSSION: Craniospinal irradiation showed the strongest effect on attentional reaction times. The association between decreased cerebellar tissue and RT doses suggests radiation-induced atrophy, which might have additional impact.