Correlation of Intraoperative 5-ALA-Induced Fluorescence Intensity and Preoperative 11 C-Methionine PET Uptake in Glioma Surgery

• Published in: Cancers 2022-03, Vol.14 (6)
• Main Authors: Shimizu, Kazuhide, Tamura, Kaoru, Hara, Shoko, Inaji, Motoki, Tanaka, Yoji, Kobayashi, Daisuke, Sugawara, Takashi, Wakimoto, Hiroaki, Nariai, Tadashi, Ishii, Kenji, Sakuma, Ichiro, Maehara, Taketoshi
• Format: Article
• Language: English
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers14061449

5-Aminolevulinic acid (5-ALA) is widely employed to assist fluorescence-guided surgery for malignant brain tumors. Positron emission tomography with C-methionine (MET-PET) represents the activity of brain tumors with precise boundaries but is not readily available. We hypothesized that quantitative 5-ALA-induced fluorescence intensity might correlate with MET-PET uptake in gliomas. Adult patients with supratentorial astrocytic gliomas who underwent preoperative MET-PET and surgical tumor resection using 5-ALA were enrolled in this prospective study. The regional tumor uptake of MET-PET was expressed as the ratio of standardized uptake volume max to that of the normal contralateral frontal lobe. A spectrometric fluorescence detection system measured tumor specimens' ex vivo fluorescence intensity at 635 nm. Ki-67 index and IDH mutation status were assessed by histopathological analysis. Use of an antiepileptic drug (AED) and contrast enhancement pattern on MRI were also investigated. Thirty-two patients, mostly with Glioblastoma IDH wild type (46.9%) and anaplastic astrocytoma IDH mutant (21.9%), were analyzed. When the fluorescence intensity was ranked into four groups, the strongest fluorescence group exhibited the highest mean MET-PET uptake and Ki-67 index values. When rearranged into fluorescence Visible or Non-visible groups, the Visible group had significantly higher MET-PET uptake and Ki-67 index compared to the Non-visible group. Contrast enhancement on MRI and IDH wild type tumors were more frequent among the Visible group. AED use did not correlate with 5-ALA-induced fluorescence intensity. In astrocytic glioma surgery, visible 5-ALA-induced fluorescence correlated with high MET-PET uptake, along with a high Ki-67 index.