QOL-24. DIFFERENTIAL IMPACT OF TUMOR LOCATION, LOCAL AND CRANIOSPINAL IRRADIATION ON NEUROPSYCHOLOGICAL LONG-TERM OUTCOME IN CHILDREN WITH MEDULLOBLASTOMA, EPENDYMOMA AND SUPRATENTORIAL PNET: A LONGITUDINAL MULTICENTER OUTCOME ASSESSMENT OF CHILDREN FROM THE HIT-2000 AND HIT-REZ TRIALS

Neurocognitive deficits are frequent in childhood brain tumor survivors and affect mental intelligence, psychomotor and executive abilities. The differential impact of factors such as disease (location, histology) or treatment (local (LI) vs. craniospinal irradiation (CSI)) on these parameters is not fully understood. Between 2007–2011 and 2013–2017 300 testings were performed on-site by one neuropsychologist. Of these, 274 tests from n=208 children with medulloblastoma (MB), ependymoma (EP) and supratentorial embryonal tumors (SET) <4 years at diagnosis are currently included into the analysis. Applied tests included the Bayley II, WUEP-KD, K-ABC, tapping speed (TS), CPT_Hits/CPT_DT, and, as a new score, CPT_Power which integrates the latter. Treatment consisted of surgery and chemotherapy ± LI/CSI. All children receiving CSI and MB children with LI showed substantial deficits in general intelligence scores. In contrast, children with MB or SET without CSI/LI and those with EP receiving LI performed surprisingly well after 2 and 5 years follow-up. Motor function (TS) was reduced in all children except those with SET without irradiation. Of note, mental processing speed (as measured in CPT_Power) was not essentially reduced in MB and EP patients, indicating that mental processing is less affected than motor speed (TS) in children with infratentorial tumors. In conclusion, our data show that besides the established detrimental effects of CSI on general intelligence, infratentorial tumor location is a main risk factor for motor dysfunction irrespective of irradiation. Appropriate sensitive testing tools are warranted to assess cognitive function without the interfering influence of motor dysfunction.