Abstract
PURPOSE: To assess the rate of neural stem cell compartment (NSC) involvement in World Health Organization (WHO) grade II gliomas treated at our institution, and whether involvement of NSC at presentation influenced outcomes. METHODS AND MATERIALS: 95 cases were reviewed. Rates of NSC involvement were assessed at presentation and (where applicable) recurrence and/or transformation. We further assessed whether NSC involvement influenced overall survival (OS), rate of recurrence (RR), rate of transformation (RT) to high grade glioma (HGG, WHO grade 3-4), time to recurrence (TTR), overall survival from time of recurrence (OSR), and overall survival from time of transformation (OST). Mean outcomes were compared using paired student t test, whereas incident rates were compared using Fisher's Exact Test. RESULTS: Mean duration of follow up was 48.6 months (60.8 months for survivors). NSC was involved in 77/95 cases (81.1%).20/25 recurrent tumors involved NSC (80%), and 20/22 transformed cases involved NSC (90.9%). 22/25 recurrent tumors had transformed to HGG (88%), and 19/22 recurrent HGG involved NSC (86.4%). There were trends toward worse mean OS for NSC+ patients: all cases (46.3 vs. 57.7 mos., p.31), recurrent cases (61 vs. 81.3 mos., p.25), and transformed cases (61.7 vs. 92 mos., p.36). There was shorter mean TTR (37.2 vs. 52.2 mos., p.54), OSR (29.6 vs. 41.2 mos., p.52), and OST (30.1 vs. 50.3 mos., p.52) in NSC+ patients, but differences were not statistically significant. CONCLUSIONS: We found high rates of NSC involvement in our adult WHO grade II glioma patients at presentation, and also at the time of recurrence and/or transformation to high grade disease. We identified a trend toward worse outcomes in tumors involving NSC, but differences did not reach statistical significance, possibly due to our limited number of patients. Involvement of NSC at presentation does not appear to influence rates of recurrence.