1.
Differential Diagnosis between Low-Grade and High-Grade Astrocytoma Using System A Amino Acid Transport PET Imaging with C-11-MeAIB: A Comparison Study with C-11-Methionine PET Imaging.
Nishii, R, Higashi, T, Kagawa, S, Arimoto, M, Kishibe, Y, Takahashi, M, Yamada, S, Saiki, M, Arakawa, Y, Yamauchi, H, et al
Contrast media & molecular imaging. 2018;:1292746
Abstract
INTRODUCTIONS [N-methyl-C-11]α-Methylaminoisobutyric acid (MeAIB) is an artificial amino acid radiotracer used for PET study, which is metabolically stable in vivo. In addition, MeAIB is transported by system A neutral amino acid transport, which is observed ubiquitously in all types of mammalian cells. It has already been shown that MeAIB-PET is useful for malignant lymphoma, head and neck cancers, and lung tumors. However, there have been no reports evaluating the usefulness of MeAIB-PET in the diagnosis of brain tumors. The purpose of this study is to investigate the efficacy of system A amino acid transport PET imaging, MeAIB-PET, in clinical brain tumor diagnosis compared to [S-methyl-C-11]-L-methionine (MET)-PET. METHODS Thirty-one consecutive patients (male: 16, female: 15), who were suspected of having brain tumors, received both MeAIB-PET and MET-PET within a 2-week interval. All patients were classified into two groups: Group A as a benign group, which included patients who were diagnosed as low-grade astrocytoma, grade II or less, or other low-grade astrocytoma (n=12) and Group B as a malignant group, which included patients who were diagnosed as anaplastic astrocytoma, glioblastoma multiforme (GBM), or recurrent GBM despite prior surgery or chemoradiotherapy (n=19). PET imaging was performed 20 min after the IV injection of MeAIB and MET, respectively. Semiquantitative analyses of MeAIB and MET uptake using SUVmax and tumor-to-contralateral normal brain tissue (T/N) ratio were evaluated to compare these PET images. ROC analyses for the diagnostic accuracy of MeAIB-PET and MET-PET were also calculated. RESULTS In MeAIB-PET imaging, the SUVmax was 1.20 ± 1.29 for the benign group and 2.94 ± 1.22 for the malignant group (p < 0.005), and the T/N ratio was 3.77 ± 2.39 for the benign group and 16.83 ± 2.39 for the malignant group (p < 0.001). In MET-PET, the SUVmax was 3.01 ± 0.94 for the benign group and 4.72 ± 1.61 for the malignant group (p < 0.005), and the T/N ratio was 2.64 ± 1.40 for the benign group and 3.21 ± 1.14 for the malignant group (n.s.). For the analysis using the T/N ratio, there was a significant difference between the benign and malignant groups with MeAIB-PET with p < 0.001. The result of ROC analysis using the T/N ratio indicated a better diagnosis accuracy for MeAIB-PET for brain tumors than MET-PET (p < 0.01). CONCLUSIONS MeAIB, a system A amino acid transport-specific radiolabeled agents, could provide better assessments for detecting malignant type brain tumors. In a differential diagnosis between low-grade and high-grade astrocytoma, MeAIB-PET is a useful diagnostic imaging tool, especially in evaluations using the T/N ratio. CLINICAL TRIAL REGISTRATION This trial was registered with UMIN000032498.
2.
Therapeutic strategy of untreated de novo acute myeloid leukemia in the elderly: the efficacy of continuous drip infusion with low dose cytarabine and etoposide.
Tsurumi, H, Kanemura, N, Hara, T, Kasahara, S, Yamada, T, Sawada, M, Oyama, M, Moriwaki, H
Journal of cancer research and clinical oncology. 2007;(8):547-53
Abstract
PURPOSE To evaluate the efficacy and safety of a novel low dose chemotherapy as a remission induction regimen for elderly de novo AML patients ineligible for intensive chemotherapy. METHOD Fifty consecutive patients, aged 60 to 85, with untreated de novo AML were enrolled. Patients with poor PS or defined non-hematological complications were given continuous drip infusion of low dose cytarabine (Ara-C), 20 mg/body and etoposide (VP-16), 50 mg/body for 10 days (AV group). Patients without those comorbidities were given intensive induction therapy (S group). After achieving complete remission (CR), S group patients and those with improved PS in AV group received consolidation chemotherapy with intensive regimen (S-S or AV-S group), and other patients received AV regimen repeatedly (AV-AV group). RESULTS Eighteen (64%; 95% confidence interval (CI), 0.47-0.82) of 28 patients in AV group and 16 (73%; 95% CI, 0.54-0.91) of 22 patients in S group achieved CR, respectively. The 1-year OS rates of the patients in the AV-AV group (n = 9), AV-S group (n = 9), and S-S group (n = 16) were 22, 81, and 78%, respectively. Although the sample size was small, no significant difference was observed for the 1-year OS rate between the AV-S and S-S groups. Regimen related death were 4 patients in S group, while no patient in AV group. CONCLUSION Therapeutic strategy consisting of remission induction using AV regimen and consolidation using intensive regimen after improving PS is beneficial in the management of elderly AML patients who have difficulty in tolerating for intensive induction chemotherapy.