[en] Purpose: To evaluate the effects of cranial radiotherapy (RT) on cognitive function in patients with supratentorial low-grade glioma. Methods and Materials: Twenty adult patients with supratentorial low-grade glioma were treated with 50.4 Gy (10 patients) or 64.8 Gy (10 patients) localized RT. The patients then were evaluated with an extensive battery of psychometric tests at baseline (before RT) and at approximately 18-month intervals for as long as 5 years after completing RT. To allow patients to serve as their own controls, cognitive performance was evaluated as change in scores over time. All patients underwent at least two evaluations. Results: Baseline test scores were below average compared with age-specific norms. At the second evaluation, the groups' mean test scores were higher than their initial performances on all psychometric measures, although the improvement was not statistically significant. No changes in cognitive performance were seen during the evaluation period when test scores were analyzed by age, treatment, tumor location, tumor type, or extent of resection. Conclusions: Cognitive function was stable after RT in these patients evaluated prospectively during 3 years of follow-up. Slight improvements in some cognitive areas are consistent with practice effects attributable to increased familiarity with test procedures and content

[en] Purpose: A prognostic index for survival was constructed and validated from patient data from two European Organisation for Research and Treatment of Cancer (EORTC) radiation trials for low-grade glioma (LGG). We sought to independently validate this prognostic index with a separate prospectively collected data set (Intergroup 86-72-51). Methods and Materials: Two hundred three patients were treated in a North Central Cancer Treatment Group-led trial that randomized patients with supratentorial LGG to 50.4 or 64.8 Gy. Risk factors from the EORTC prognostic index were analyzed for prognostic value: histology, tumor size, neurologic deficit, age, and tumor crossing the midline. The high-risk group was defined as patients with more than two risk factors. In addition, the Mini Mental Status Examination (MMSE) score, extent of surgical resection, and 1p19q status were also analyzed for prognostic value. Results: On univariate analysis, the following were statistically significant (p < 0.05) detrimental factors for both progression-free survival (PFS) and overall survival (OS): astrocytoma histology, tumor size, and less than total resection. A Mini Mental Status Examination score of more than 26 was a favorable prognostic factor. Multivariate analysis showed that tumor size and MMSE score were significant predictors of OS whereas tumor size, astrocytoma histology, and MMSE score were significant predictors of PFS. Analyzing by the EORTC risk groups, we found that the low-risk group had significantly better median OS (10.8 years vs. 3.9 years, p < 0.0001) and PFS (6.2 years vs. 1.9 years, p < 0.0001) than the high-risk group. The 1p19q status was available in 66 patients. Co-deletion of 1p19q was a favorable prognostic factor for OS vs. one or no deletion (median OS, 12.6 years vs. 7.2 years; p = 0.03). Conclusions: Although the low-risk group as defined by EORTC criteria had a superior PFS and OS to the high-risk group, this is primarily because of the influence of histology and tumor size. Co-deletion of 1p19q is a prognostic factor. Future studies are needed to develop a more refined prognostic system that combines clinical prognostic features with more robust molecular and genetic data.