Children treated for medulloblastoma and supratentorial primitive neuroectodermal tumor in Norway from 1974 through 2013: Unexplainable regional differences in survival

BACKGROUND

A previous study based on Norwegian Cancer Registry data suggested regional differences in overall survival (OS) after treatment for medulloblastoma (MB) and supratentorial primitive neuroectodermal tumor (CNS-PNET) in Norway. The purpose of the present study was to confirm in an extended cohort whether there were regional differences in outcome or not, and if so try to identify possible explanations.

MATERIAL AND METHODS

Data from patients aged 0-20 years diagnosed with and treated for MB/CNS-PNET at all four university hospitals in Norway from 1974 to 2013 were collected and compared.

RESULTS

Of 266 identified patients, 251 fulfilled inclusion criteria. MB was diagnosed in 200 and CNS-PNET in 51 patients. Five-year OS and event-free survival (EFS) were 59% and 52%, respectively. There was a significant difference in five-year OS and EFS between MB and CNS-PNET patients; 62% versus 47% (P =  0.007) and 57% versus 35% (P < 0.001). In multivariable analysis, two factors were found to significantly contribute to improved five-year OS and EFS, whereas one factor contributed to improved five-year OS only. Gross total resection (GTR) versus non-GTR (hazard ratio [HR] 0.53, P =  0.003; HR 0.46, P < 0.001) and cerebrospinal irradiation (CSI) versus non-CSI (HR 0.24, P < 0.001; HR 0.28, P < 0.001) for both, and treatment outside Oslo University Hospital for OS only (HR 0.64, P =  0.048).

CONCLUSION

Survival was comparable with data from other population-based studies, and the importance of GTR and CSI was confirmed. The cause for regional survival differences could not be identified.

Neuroanatomical correlates of verbal fluency in early Alzheimer's disease and normal aging

Verbal fluency (VF) impairments occur early in Alzheimer's disease (AD) and to a lesser extent also in normal aging. However, the neural underpinnings of these impairments are not fully understood. The present study evaluated whether VF impairments in early AD and normal aging rely upon common or different neuroanatomical correlates. We examined the association between VF performance and brain structure in 18 mild AD patients and 24 healthy elderly. Linear regressions were performed between accuracy and time intervals in VF scores and structural measurements of cerebral gray matter (GM) and white matter (WM) using MRI. Results showed that semantic VF correlated exclusively with GM in cerebellum, left temporal fusiform cortex, and WM in uncinate fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Phonemic VF showed unique associations between intervals and WM in left-hemisphere tracts. The association between GM in hippocampus, subcortical structures and semantic accuracy differentiated patients from controls. Results showed that VF impairments are primarily associated with same structural brain changes in AD as in healthy elderly but at exaggerated levels. However, specific VF deficiencies and their underlying neural correlates exist and these clearly differentiate the initial stages of AD.