Predicting the IDH1 mutation status of diffuse gliomas by intraoperative 5-aminolevulinic acid-induced fluorescence
In patients operated for malignant glioma, 5-aminolevulinic acid (5-ALA)-induced fluorescence guidance is useful. However, we occasionally experience instances of non-visible fluorescence despite a histopathological diagnosis of high-grade glioma. We sought to identify factors that facilitate the intraoperative visualization of gliomas by their 5-ALA-induced fluorescence.
Patients and methods
We reviewed data from 60 patients with astrocytic or oligodendroglial tumors who underwent tumor removal under 5-ALA-induced fluorescence guidance between January 2014 and December 2015. Their characteristics, preoperative magnetic resonance imaging (MRI) findings, histological diagnosis, and genetic profile were analyzed and univariate and multivariate statistical analyses were performed.
In 42 patients (70%) we intraoperatively observed tumor 5-ALA fluorescence. They were 2 of 8 (25%) patients with WHO grade II-, 9 of 17 (53%) with grade III-, and 31 of 35 (89%) patients with grade IV gliomas. Univariate analysis revealed a statistically significant association between 5-ALA fluorescence and the IDH1 status, 1p19q LOH, the MIB-1 labeling index, and the tumor margin, -heterogeneity, and -contrast enhancement on MRI scans (p < 0.001, p = 0.003, p = 0.007, p = 0.046, p = 0.021, and p = 0.002, respectively). Multivariate analysis showed that the IDH1 status was the only independent, statistically significant factor related to ALA-5 fluorescence (p = 0.009).
The absence of 5-ALA fluorescence in diffuse gliomas may be predictive of their IDH1 mutation status.