Association between fluorine-18-labeled fluorodeoxyglucose uptake and 1p and 19q loss of heterozygosity in World Health Organization Grade II gliomas

Object. Oligodendroglial tumors harboring combined 1p and 19q loss (1p/19q LOH) are characterized by a favorable prognosis and response to chemotherapy and radiotherapy, but detection of 1p/19q LOH relies on postoperative procedures. The authors investigated the potential of fluorine-18-labeled fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) to predict 1p/19q LOH preoperatively in tumors whose appearance on initial magnetic resonance images was consistent with that of low-grade glioma. Methods. The Study Population comprised 25 patients who had undergone preoperative FDG-PET followed by tumor resection. Neuronavigation ensured a precise match of FDG uptake with the site of biopsy. All tumor specimens were graded according to the World Health Organization (WHO) classification system. Microsatellite analysis was used to identify 1p/19q LOH. In this series, 16 of 25 gliomas corresponded to WHO Grade II. In eight of these 16, 1p/19q LOH was detected. Raised glucose utilization within the tumor was seen in the six of eight WHO Grade II gliomas with 1p/19q LOH and in none of the WHO Grade It gliomas without this genetic alteration (p = 0.003). Conclusions. These findings demonstrate the potential of FDG-PET to predict 1p/19q LOH in WHO Grade II gliomas.