Contrast enhancement (CE) is described in 10-60% of low grade gliomas (LGG). Its prognostic significance is controversial, and its correlation with IDH mutations and 1p/19q codeletion is unknown. The aim of this study is to investigate whether CE is associated with molecular characteristics of LGG and elucidate its prognostic value.
All confirmed histological cases of LGG diagnosed in a single institution between years 2000-2016 were retrospectively reviewed (n = 104). Clinical, radiological and molecular factors were collected. Spinal and brainstem localization, only-biopsied tumours with ring-like enhancement and incomplete medical records were excluded. 1p/19 codeletion analysis was performed by FISH, IDH was performed by immunohistochemistry. IDH wild-type tumours were confirmed with qPCR. Overall survival (OS) was estimated by Kaplan-Meier method.
We included 89 patients, with a median follow-up of 73.3 months. Mean age was 41.6 years, and 65.2% were male. CE was present on 25.8% of preoperative MRI, and 25.3% of patients were considered high-risk according to Pignatti score. Most were astrocytomas (67.4%) and 84.4% were surgically removed. IDH mutation was found in 66.7% of tumour samples, and 17.9% had a 1p/19q codeletion. No differences were observed amongst CE and non-CE groups, apart from age (46.6 vs 39.9 years, respectively; p = 0.041). IDH mutation (p = 0.776) and 1p/19q codeletion (p = 0.512) were evenly distributed. On univariate analysis, size >6cm (p = 0.002), CE (p = 0.026), extent of resection (p = 0.008), Pignatti score (p = 0.002) and IDH mutation (p = 0.003) were significantly associated to OS. On multivariate analysis, only CE (p = 0.009) and IDH status (p = 0.005) were independently associated to OS.
CE in LGG provides complementary and independent prognostic information to IDH and 1p/19q codeletion. Its contribution to treatment decisions requires further exploration in larger prospective cohort studies.
Clinical trial identification
Legal entity responsible for the study
Unidad de Neuro-Oncología, Institut Català d'Oncologia.
Has not received any funding.
All authors have declared no conflicts of interest.