Abstract
BACKGROUND: Oligodendroglioma (WHO grade II and III) patients are at risk to develop neurocognitive dysfunction due to oncological treatment. Our aim was to identify the correlation between cognitive impairment and volumetric brain changes in a group of oligodendroglioma long-term survivors who were exposed to chemotherapy (CT) and/or radiotherapy (RT). MATERIAL AND METHODS: Oligodendroglial tumors (2007 WHO) diagnosed between 1994 and 2015 who underwent CT and/or RT at least 2 years before were retrospectively reviewed. Fourty-eight oligodendroglioma were split into 3 groups according to the time in which treatment was completed: Group 1, 2-5 years before (n=22); Group 2, 6-10 years before (n=13); Group 3, >10 years before (n=13). We conducted a cross-sectional neuropsychological evaluation (n=48) and we compared longitudinal volumetric changes (gray matter, GM) (n=34) between post-surgical and the last follow-up magnetic resonance imaging (MRI). RESULTS: There were no differences regarding tumor or treatment-related characteristics between groups. All patients underwent RT (median dose 60 Gy, range 50-60), and nearly 80% (n=38) also received CT. More than a half of patients (71.4% in Group 1, 89% in Group 2 and 60% in Group 3) showed 1p19q codeletion. Six of 22 patients (27.3%) in Group 1, 5 of 13 (38.5%) in Group 2 and 9 of 13 (69.2%) in Group 3 exhibited cognitive deficits. Group 3 showed significant cognitive impairment compared to Group 1 (p=0.015). Specifically, Group 3 exhibited a delayed visual memory decline compared to Group 1 and 2 (p =0.001 and p=0.02, respectively) and a worsening in measures of executive functioning (Trail Making Test part A) compared to Group 1 (p=0.022). Concerning brain structural alterations, Group 3 showed a marginally significant GM volume decrease at more than 10 years since treatment (p=0.13) compared to other groups. Interestingly, patients with more severe cognitive deficits (executive functions) associated less GM volume (r=0.53, p=0.002). CONCLUSION: This study shows that long-term oligodendroglioma survivors patients who underwent standard radiation and chemotherapy treatment, mainly after 10 years of its completion, present an established cognitive impairment, especially focused on memory and executive functions, accompanied with a late GM damage (more than 10 years), thus highlighting the need of improving the current treatment strategies in patients with long expected survival.