From the Department of Neurosurgery.
Department of Surgery.
Clin Nucl Med. 2022 Jul 1;47(7):569-574. doi: 10.1097/RLU.0000000000004221. Epub 2022 Apr 22.
The aim of this study was to clarify whether PET with 11C-methyl-l-methionine (11C-met PET) can predict consequential outcomes at the time of discontinuing temozolomide (TMZ)-adjuvant chemotherapy in patients with residual isocitrate dehydrogenase gene (IDH)-mutant lower-grade glioma.
Among 30 patients showing residual lesions of IDH-mutant lower-grade glioma, we compared the tumor-to-normal brain tissue ratio of standardized uptake values (SUVT/N) from 11C-met PET at the time of discontinuing TMZ-adjuvant chemotherapy with putative predictive factors including age, Karnofsky Performance Scale, number of courses of adjuvant therapy, residual tumor size, and promotor methylation status of O6-methylguanine-DNA methyl-transferase gene (MGMT). For each factor, progression-free survival (PFS) was compared between groups divided by cutoff values, determined to predict tumor relapse using receiver operating characteristic curves for each factor. Univariate and multivariate analyses were conducted using log-rank testing and Cox regression analysis, respectively. In addition, PFS was compared between patients grouped by combined findings from multiple predictors identified from univariate and multivariate analyses.
Univariate and multivariate analyses identified SUVT/N from 11C-met PET and MGMT methylation status as independent predictors of outcomes after TMZ discontinuation. When comparing 3 groups assigned by the combination of MGMT and SUVT/N findings, PFS differed significantly among groups.
The present study suggested that 11C-met PET at the time of discontinuing TMZ-adjuvant chemotherapy allows prediction of outcomes at least comparable to MGMT methylation status in patients with residual IDH-mutant lower-grade glioma. Further, 11C-met PET allows more precise prediction of outcomes by assessment in combination with MGMT findings.
本研究旨在阐明在停止替莫唑胺（TMZ）辅助化疗时，利用 11C-甲基-L-蛋氨酸（11C-met PET）进行正电子发射断层扫描（PET）是否可以预测残留异柠檬酸脱氢酶基因（IDH）突变型低级别胶质瘤患者的后续结局。
在 30 例表现出 IDH 突变型低级别胶质瘤残留病变的患者中，我们比较了停止 TMZ 辅助化疗时 11C-met PET 的标准化摄取值（SUVT/N）与年龄、卡诺夫斯基表现量表、辅助治疗疗程数、残留肿瘤大小以及 O6-甲基鸟嘌呤-DNA 甲基转移酶基因（MGMT）启动子甲基化状态等潜在预测因素之间的关系。对于每个因素，使用每个因素的受试者工作特征曲线来确定截断值，根据截断值将肿瘤无进展生存（PFS）分组，并比较各组之间的 PFS。使用对数秩检验和 Cox 回归分析进行单变量和多变量分析。此外，还比较了根据单变量和多变量分析中确定的多个预测因子的联合发现对患者进行分组后的 PFS。
单变量和多变量分析均确定 11C-met PET 的 SUVT/N 和 MGMT 甲基化状态是 TMZ 停药后结局的独立预测因素。当比较按 MGMT 和 SUVT/N 发现组合分组的 3 组时，各组之间的 PFS 差异有统计学意义。
本研究表明，在停止 TMZ 辅助化疗时进行 11C-met PET 可预测 IDH 突变型低级别胶质瘤残留患者的结局，其结果至少与 MGMT 甲基化状态相当。此外，通过与 MGMT 发现相结合进行评估，11C-met PET 可更精确地预测预后。
