11C-methionine uptake and intraoperative 5-aminolevulinic acid-induced fluorescence as separate index markers of cell density in glioma.

BACKGROUND: The extent of tumor resection is acknowledged as 1 of the prognostic factors for glioma. 5-Aminolevulinic acid (5-ALA)-induced fluorescence guidance and neuronavigation integrated with 11C-methionine positron emission tomography (PET) are widely utilized under the expectation of improving the extent of resection. These 2 novel approaches are beneficial for glioma resections, and the combination of these approaches appears rational. However, biological characteristics reflecting 5-ALA-induced fluorescence and 11C-methionine uptake have not been clearly elucidated, and studies about the relationship between 5-ALA-induced fluorescence and 11C-methionine uptake have been limited. The present study aimed to clarify this issue. METHODS: Data from 11 consecutive patients harboring astrocytic tumors were analyzed: 2 grade II and 2 grade III, and 7 grade IV tumors were included. Thirty samples from these patients were obtained from the relative periphery of each tumor. Relationships among histology, 5-ALA-induced fluorescence and 11C-methionine uptake were analyzed by stereotactic sampling and image analysis. RESULTS: Uptake of 11C-methionine correlated with cell density ( R2 = 0.322, P = .0059). Cell density was higher in fluorescence-positive areas than in negative areas (2760 ± 1080 vs 1450 ± 1380/mm2, P = .0132). Although both 11C-methionine uptake and fluorescence seemed to correlate with cell density, no significant difference in 11C-methionine uptake was seen between fluorescence-positive and -negative areas ( P = .367). Multiple linear regression analysis revealed 11C-methionine uptake and 5-ALA-induced fluorescence as independent indices for tumor cell density. CONCLUSIONS: These results indicate that 5-ALA fluorescence and 11C-methionine PET image are separate index markers for cytoreduction surgery of gliomas. Cancer 2011;. © 2011 American Cancer Society. [ABSTRACT FROM AUTHOR]