Prognostic significance of 18F-FDG PET parameters and plasma Epstein-Barr virus DNA load in patients with nasopharyngeal carcinoma.

UNLABELLED: The plasma concentration of Epstein-Barr virus (EBV) DNA is associated with tumor burden and prognosis in patients with nasopharyngeal carcinoma (NPC), but data on the relationship between viral load and (18)F-FDG PET functional parameters are lacking. We examined the association of (18)F-FDG PET functional parameters and EBV DNA load with the clinicopathologic characteristics and clinical outcomes of patients with NPC. METHODS: One hundred eight patients with NPC who underwent (18)F-FDG PET before treatment were included in this study. We determined total lesion glycolysis (TLG) of the primary tumor, the cervical nodes, and their combination and the maximal standardized uptake value of the primary tumor and cervical lymph nodes. EBV DNA was measured by real-time polymerase chain reaction. RESULTS: EBV DNA was significantly associated with total TLG (R(2) = 0.589). Total TLG values had the highest correlation with EBV DNA load and were significantly associated with tumor, nodal, and overall stages. However, tumor TLG greater than the median (>65 g) was the only parameter significantly associated with overall, local recurrence-free, disease-free, and distant metastasis-free survivals (P = 0.033, 0.014, <0.001, and 0.023, respectively). After allowance for potential confounders, tumor TLG retained its independent significance for overall and disease-free survival rates (P = 0.045 and 0.006, respectively). CONCLUSION: Total TLG values are primarily associated with tumor burden and clinical stage, whereas tumor TLG is the best predictor of patient survival after treatment.

Whole-body biodistribution and brain PET imaging with [18F]AV-45, a novel amyloid imaging agent--a pilot study.

PURPOSE: The compound (E)-4-(2-(6-(2-(2-(2-(18)F-fluoroethoxy)ethoxy)ethoxy) pyridin-3-yl)vinyl)-N-methylbenzenamine ([(18)F]AV-45) is a novel radiopharmaceutical capable of selectively binding to beta-amyloid (A beta) plaques. This pilot study reports the safety, biodistribution, and radiation dosimetry of [(18)F]AV-45 in human subjects. METHODS: In vitro autoradiography and fluorescent staining of postmortem brain tissue from patients with Alzheimer's disease (AD) and cognitively healthy subjects were performed to assess the specificity of the tracer. Biodistribution was assessed in three healthy elderly subjects (mean age: 60.0+/-5.2 years) who underwent 3-h whole-body positron emission tomography (PET)/computed tomographic (CT) scans after a bolus injection of 381.9+/-13.9 MBq of [(18)F]AV-45. Another six subjects (three AD patients and three healthy controls, mean age: 67.7+/-13.6 years) underwent brain PET studies. Source organs were delineated on PET/CT. All subjects underwent magnetic resonance imaging (MRI) for obtaining structural information. RESULTS: In vitro autoradiography revealed exquisitely high specific binding of [(18)F]AV-45 to postmortem AD brain sections, but not to the control sections. There were no serious adverse events throughout the study period. The peak uptake of the tracer in the brain was 5.12+/-0.41% of the injected dose. The highest absorbed organ dose was to the gallbladder wall (184.7+/-78.6 microGy/MBq, 4.8 h voiding interval). The effective dose equivalent and effective dose values for [(18)F]AV-45 were 33.8+/-3.4 microSv/MBq and 19.3+/-1.3 microSv/MBq, respectively. CONCLUSION: [(18)F]AV-45 binds specifically to A beta in vitro, and is a safe PET tracer for studying A beta distribution in human brain. The dosimetry is suitable for clinical and research application.

18F-FDG PET for retropharyngeal lymph node metastasis in oropharyngeal and hypopharyngeal cancers: impact on diagnosis and prediction analysis.

PURPOSE: Retropharyngeal lymph node (RPLN) metastasis is a poor prognosticator in oropharyngeal and hypopharyngeal cancers. The purpose of this study is to evaluate the impact of F-fluorodeoxyglucose positron emission tomography (F-FDG PET) on the diagnosis and predictor analysis of RPLN in these cancers. METHODS: We enrolled patients with oropharyngeal and hypopharyngeal cancers before receiving definitive treatment. Staging was performed by F-FDG PET and conventional imaging modalities. Differences in RPLN metastasis detection rates were compared. Independent predictors of RPLN involvement were also assessed. RESULTS: A total of 224 patients were investigated. RPLN involvement was identified in 17% of the study patients. In 18% of the 38 patients with RPLN involvement, RPLN metastases were identified by F-FDG PET only. Only 4% of the patients with oropharyngeal cancer and RPLN metastasis were not identified without the use of F-FDG PET, compared with 46% of patients with hypopharyngeal cancer. In multivariate analysis, posterior pharyngeal wall tumor (P=0.02) or the presence of ipsilateral level V lymph node metastasis (P=0.025) were independent predictors of RPLN involvement in hypopharyngeal cancer. In oropharyngeal cancer, no factors retained their independent significance. CONCLUSION: We concluded that F-FDG PET is helpful in detecting RPLN metastasis in hypopharyngeal cancer. The presence of ipsilateral level V lymph node metastasis or tumors originating from the posterior pharyngeal wall can predict RPLN involvement in hypopharyngeal cancer and might represent an indication for elective irradiation of this nodal basin. However, regional lymph node involvement is not an independent predictor in oropharyngeal cancer. The predictor for RPLN metastasis seems to change after the introduction of PET.