CLINICO-MOLECULAR CORRELATES OF QUALITY OF SURVIVAL AND NEUROCOGNITIVE OUTCOMES IN MEDULLOBLASTOMA; A META-ANALYSIS OF THE SIOP-UKCCSG-PNET3 AND HIT-SIOP-PNET4 TRIALS

Abstract Determinants of survivorship outcomes are emerging from limited studies of medulloblastoma (MB) survivors. We undertook an integrated analysis of biological (tumour group, host genetics) and clinico-demographic features in patients treated on the SIOP-UKCCSG-PNET3 and HIT-SIOP-PNET4 clinical trials with available quality of survival (QoS) data (n=218), to determine key correlates of survivorship, and their clinical potential. Treatment/demographic factors and molecular subgroup (MBWNT, MBSHH, MBGrp3, MBGrp4) were assessed against health status, behavioural functioning, and health-related quality of life (HrQoL). In DNA from HIT-SIOP-PNET4 (n=74), 39 candidate SNPs with known modifying effects on neurocognitive outcomes (e.g., involved in oxidative stress/inflammation) were genotyped and assessed against Wechsler Intelligence Scale (WISC) scores. As expected, MBSHH was associated with improved HrQoL, but subgroup did not associate further with QoS outcomes. SIOP-UKCCSG-PNET3 patients receiving chemotherapy before craniospinal irradiation (CSI) had significantly lower health status (p=0.021) and behavioural functioning (p<0.016) compared to patients treated with CSI alone, and those treated on both arms (maintenance chemotherapy and hyperfractionated (36Gy) or standard (23.4Gy) CSI) of HIT-SIOP-PNET4. SIOP-UKCCSG-PNET3 patients receiving CSI-only had better HrQoL scores than those who received pre-CSI chemotherapy and both HIT-SIOP-PNET4 arms (p=0.004). Females reported worse HrQoL/behavioural functioning across both trials (p<0.04). In HIT-SIOP-PNET4, longer intervals from diagnosis to CSI predicted worse HrQoL/health status (p<0.05). Neither molecular group nor clinico-demographic features tested were associated with neurocognition. In contrast, 6 SNPs significantly associated with ≥1 WISC domain; 4/6 showed multiple associations and were independently prognostic; further associations were apparent at the gene/pathway level. This large, integrated and multi-disciplinary analysis of two independent trials cohorts has revealed multiple factors predictive of medulloblastoma survivorship including treatment (chemotherapy, time to CSI), tumour (molecular group) and host genetic factors. Assessment in further prospective series are required to determine their potential as a basis for modifications to disease management.