F-18-5-fluorouracil dynamic positron emission tomography/computed tomography shows decreased tracer activity after bevacizumab in colorectal metastases NUCLEAR MEDICINE COMMUNICATIONS Zissen, M. H., Kunz, P., Subbarayan, M., Chin, F. T., Conti, P. S., Fisher, G. A., Quon, A. 2011; 32 (5): 343-347


The aim of this study was to evaluate the potential of fluorine-18 (F)-5-fluorouracil (F-5-FU) positron emission tomography/computed tomography (PET/CT) to show differences in 5-FU activity in metastatic colorectal cancer before and after treatment with bevacizumab.This was a pilot study of five patients with newly diagnosed and untreated metastatic colorectal adenocarcinoma. The presence of cancer was confirmed by histopathological analysis before enrollment. Patients underwent F-5-FU PET/CT scanning before treatment and at approximately 24 h postbevacizumab. PET/CT scanning consisted of a dynamic acquisition of images taken 0-20 min after injection of radiotracer. The degree of F-5-FU activity at the metastatic sites was assessed using visual interpretation and semiquantitative standardized uptake value analyses.The sizes of the metastatic lesions ranged from the smallest lesion measuring 3.04 × 1.50 cm to the largest measuring 4.19 × 2.76 cm. By drawing regions of interest, time-activity curves were generated at each tumor site and area under the curve (AUC) analyses were carried out. At baseline, during the first 5 min after F-5-FU injection the mean AUCtumor/AUCaorta ratio was 1.24 ± 0.30 (range, 0.424-2.14). Less than 24 h after the administration of bevacizumab, the AUCtumor/AUCaorta ratio decreased to 1.06 ± 0.32 (range, 0.23-2.13, P=0.04), which represented an average decline of 20.2% (range, 0.4-45%). Radiotracer uptake on the 5, 10, 15, and 20-min images did not show any significant change between baseline and posttreatment. Follow-up CT imaging showed stable tumor size in one patient and a decrease in metastasis size in the remaining four patients.In this pilot study of five patients with metastatic colorectal carcinoma, F-5-FU PET/CT scanning showed a significant perfusion-related decrease in tracer activity 24 h postbevacizumab.

View details for DOI 10.1097/MNM.0b013e328344894b

View details for PubMedID 21412178