NCOG-36. DOSIMETRY AND COGNITIVE FUNCTION AFTER RADIATION THERAPY IN LOW GRADE GLIOMAS

Abstract

Abstract PURPOSE We found that cognitive function remained stable following radiotherapy with concurrent and adjuvant temozolomide (RT+TMZ) in low-grade glioma (LGG) patients evaluated prospectively up to 2 years. This study evaluates the effects of radiotherapy dosimetry on neurocognitive function in a larger group of molecularly defined LGG patients treated with radiotherapy (RT). METHODS A total of 39 LGG patients were evaluated with comprehensive psychometric tests at baseline (prior to RT) and at various time intervals following RT. Patients served as their own controls by evaluating change in scores over time. Dosimetric parameters included mean and maximum dose to the pituitary, mean and maximum dose to the hypothalamus, mean dose to contralateral hippocampus, brain, cochlea, and PTV volume. Correlation between dosimetry and neurocognitive tests were assessed by Spearman correlation for the baseline correlation and Cox proportional hazard regression analysis for the survival analysis. RESULTS Patients were followed for a median of 60 months. Overall, patients showed group mean test scores similar to their initial performances following radiotherapy on all psychometric measures. There was a significant correlation between mean dose to cochlea (p=0.006), pituitary (p=0.035), mean PTV volume (0.019) and neurocognitive outcome.. CONCLUSION Cognitive function remained stable following radiotherapy in LGG patients evaluated prospectivelys. There was a significant correlation between specific dosimetric endpoints and neurocognitive outcomes over time. Further study needs to be done in a larger population to validate these findings.