gms | German Medical Science

Objective: High-grade gliomas (HGG) are the most common malignant primary brain tumor in adults. During the course of disease, several challenges occur, like measuring tumor burden, monitoring of treatment response, estimating the patient’s prognosis and distinguishing between true progression and pseudo-progression. Currently, diagnosis and monitoring of HGG depend on invasive procedures or on technically extensive and costly imaging techniques with in parts restricted informational value. So far, no blood-based biomarker has been established in the clinical routine to address the mentioned challenges. The aim of this study was to analyze the present evidence on blood-based biomarkers for HGG.

Methods: PubMed, Web of Sciences, Scopus and Cochrane Library databases were systematically searched for publications before 30th march 2018 reporting on associations of blood-based biomarkers in HGG patients with different endpoints as overall survival, progression-free survival and postoperative monitoring. For each included study the methodological and content quality was assessed. The tested blood-based biomarkers were classified into 4 different groups according to their class of evidence. Statistical analysis was conducted using Student’s t-test for normally distributed and the Mann-Whitney U test for non-normally-distributed data. Differences with a P-value of 0.05 or less were considered as statistically significant.

Results: 1680 unique records were identified. Of these, 170 original articles were included to this review. 415 different blood-based biomarkers analyzed in 15.041 patients with HGG as also their corresponding recurrent tumors. The mean number of patients was 88.48 patients in each study. The mean total number of analyzed patients for every single biomarker was 112.84. Ten predictive biomarkers reached level II of evidence: α2-Heremans-Schmid glycoprotein, Albumin, Glucose, Insulin-like growth factor- binding protein 2, macrophage inflammatory protein 1δ, Macrophage inflammatory protein 3ß, neutrophil-lymphocyte ratio, red blood cell distribution width, soluble glycoprotein 130 and chitinase-3like protein 1. No biomarker achieved level I of evidence.

Conclusion: In this review, 10 blood-based biomarkers were selected as most promising biomarkers for HGG. To further assess the clinical significance of these biomarkers, the evaluation in a larger cohort of HGG and their corresponding subgroups would be necessary.