Ki-67 immunostaining in pancreatic cancer and chronic active pancreatitis: does in vivo FDG uptake correlate with proliferative activity?

UNLABELLED: PET with 18F-FDG has been shown to be useful in the detection and staging of pancreatic cancer. However, whether FDG uptake is dependent on proliferative activity is still unclear. The aim of this prospective study was to evaluate a probable correlation between FDG uptake and proliferative activity in benign and malignant pancreatic tumors. METHODS: Our series consisted of 23 patients with pancreatic cancer and 9 patients with chronic active pancreatitis (CAP). FDG PET was performed within 2 wk before surgery, and standardized uptake values (SUVs) were calculated for benign and malignant pancreatic tumors. Patients were selected when focally increased FDG uptake in previously known pancreatic tumors was present. Proliferation fraction was measured in tissue specimens using the anti-Ki-67 antibody MIB-1. A computer-assisted imaging system was used for quantification of nuclear Ki-67 immunostaining. Immunohistochemical findings were correlated to SUVS: RESULTS: Pancreatic cancer showed both intense nuclear staining of Ki-67 (39% +/- 16%) and high FDG uptake (SUV = 3.6 +/- 1.6). However, no significant correlation was found between in vivo FDG uptake and Ki-67 immunoreactivity (P = 0.65). By contrast, Ki-67 nuclear staining was significantly lower (3.8% +/- 2.7%, P < 0.05) in CAP, whereas FDG uptake was in the same range as for pancreatic cancer (SUV = 3.5 +/- 1.8). CONCLUSION: FDG uptake did not correlate with proliferative activity in pancreatic cancer. Proliferative activity was tenfold higher in malignant pancreatic tumors than in benign tumors associated with CAP, whereas FDG uptake in vivo did not differ significantly. Thus, a PET tracer indicating cellular proliferation should better differentiate between cancer and inflammatory lesions than do metabolic markers such as FDG.

2-(fluorine-18)fluoro-2-deoxy-D-glucose positron emission tomography in the detection and staging of malignant lymphoma. A bicenter trial.

BACKGROUND: The authors undertook a prospective evaluation of the clinical value of 2-fluoro [18-]-2-deoxyglucose positron emission tomography (FDG-PET) in the detection and staging of malignant lymphoma compared with computed tomography (CT) and bone marrow biopsy (BMB). METHODS: Fifty-two consecutive patients with untreated malignant lymphoma were evaluated prospectively in a bicenter study. FDG-PET, CT, and BMB were performed for investigating lymph node/extranodal manifestations and bone marrow infiltration. Thirty-three percnt of the discrepant results were verified by biopsy, magnetic resonance imaging, or clinical follow-up (range, 4-24 month). RESULTS: Altogether, 1297 anatomic regions (lymph nodes, organs, and bone marrow) were evaluated. FDG-PET and CT scans were compared by receiver operating characteristic (ROC) curve analysis. The area under the ROC curve were as follows: lymph nodes, 0.996 (PET) and 0.916 (CT); extranodal, 0.999 (PET) and 0.916 (CT); supradiaphragmatic, 0.996 (PET) and 0.905 (CT); and infradiaphragmatic, 0.999 (PET) and 0.952 (CT). In these analyses, FDG-PET was significantly superior to CT (P < 0.05), except in infradiaphragmatic regions, in which the two methods produced equivalent results. In detecting bone marrow infiltration, FDG-PET was superior to CT and was equivalent to BMB. In 4 of 52 patients (8%), FDG-PET led to an upstaging and a change of therapy. CONCLUSIONS: Noninvasive FDG-PET is very accurate in the staging of malignant lymphoma. Compared with standard staging modalities (CT and BMB), PET was significantly superior and led to changes in the therapy regimen for 8% of patients.

[F-18-FDG PET for primary diagnosis differential diagnosis of pleural processes]. / F-18-FDG-PET zur Primärdiagnostik und Dignitätsbeurteilung pleuraler Prozesse.

PURPOSE: Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) has been shown to be accurate for differentiating benign from malignant pulmonary lesions. Therefore, we evaluated the capability of FDG-PET in the characterisation of pleural lesions. PATIENTS AND METHODS: PET was performed in thirteen patients with pleural or intrapulmonal tumors (three with additional pleural effusion) and in three patients with aetiologically unclear pleural effusion demonstrated by CT. In all cases the diagnosis was confirmed histologically. The PET-imaging was carried out in fasted patients 50 minutes after injection of 400-670 MBq F-18-FDG without attenuation correction. RESULTS: Twelve patients were found to have pleural or pulmonal malignomas (9 pleural mesotheliomas, 3 bronchogenic adenocarcinoma with carcinomatous pleurisy). Four patients had benign pleural changes (1 fibroma, 1 tuberculous pleurisy, 1 pleural fibrosis, 1 empyema). With FDG-PET, all 12 pleural or intrapulmonal malignomas had high FDG-uptake and were classified correctly. Due to very low or virtually deficient FDG-uptake, four histologically benign lesions were correctly interpreted as nonmalignant. CONCLUSION: These preliminary results suggest that FDG-PET is accurate in detecting malignant pleural tumors.

[Radioiodine therapy of autonomously functioning thyroid nodules and Graves' disease]. / Radiojodtherapie der funktionellen Autonomie und des M. Basedow.

We studied the effects of radioiodine therapy (RIT) for autonomously functioning thyroid nodules (AFTNs) and Graves' disease on thyroid function and size up to one year after RIT. In 230 patients with AFTNs, a dose of 300 Gy was effective in about 90% of the cases 6 months after RIT. Out of 65 patients suffering from Graves' disease, 5 patients (8%) had persisting hyperthyroidism 6 months after RIT with a dose of 150 Gy. This group consisted exclusively of patients with manifest hyperthyroidism at the time of RIT. As determined by ultrasonography 6 months after RIT, a reduction of thyroid size by about 40% and 60% was observed in patients with AFTNs and Graves' disease, respectively.