Characteristics and patterns of care of high-grade IDH-mutant gliomas in elderly patients: A French POLA network study

Abstract

Background: The characteristics of elderly patients with IDH-mutant (IDHm) highgrade gliomas (HGG) remain to be described. This study aims to describe characteristics and patterns of care of elderly patients with IDHm HGG included in the French POLA network dedicated to HGG. Method(s): The characteristics and patterns of care of elderly ( >=70 years) patients IDHm HGG were compared to those of younger patients (<70 years) with IDHm gliomas and to those of elderly patients with IDH wild-type (IDHwt) gliomas. Result(s): Out of the 1433 HGG patients included, 119 (8.3%) occurred in elderly patients. Histology consisted of 1p/19q codeleted anaplastic oligodendroglioma (71.8%), anaplastic IDHm astrocytomas (12.8%) and IDHm glioblastoma (15.4%). Median age at diagnosis was 74 years (70.2-87.1), median Karnofsky Performans Status (KPS) was 80 (50-100). Treatments consisted of a wait and scan policy (7.7%), radiotherapy (RT) alone (7.7%), chemotherapy (CT) alone (41%), RT-CT (RT-TMZ: 25.6%, RT-PCV: 15.4%) or palliative care (2.6%). The clinical, radiological and histological presentations of elderly patients IDHm HGG were different from those of elderly patients IDHwt HGG. Compared to elderly patients IDHwt HGG, elderly patients IDHm were less frequently associated with cognitive impairment (p=0.045), contrast enhancement (p=0.01) and had a lower proliferative index (Ki67) (p=0.005). In contrast, there was no difference regarding clinical, radiological and histological presentations of elderly and younger patients IDHm HGG but their management was different. Elderly patients IDHm less frequently underwent gross total resection (p=0.002) and radiotherapy (p<0.001). The median progression-free survival (PFS) and overall survival (OS) were longer for IDHm elderly patients (29.2 and 62.1months respectively) than IDHwt elderly patients (8.2 and 13.2 months respectively) but shorter than younger IDHm patients (69 months and not reached respectively). Conclusion(s): IDHm HGG in elderly show prolonged survival. However, their poorer outcome compared to younger IDHm gliomas may results from patient or tumor characteristics or from under-treatment, suggesting a role for geriatric assessment.