Serum carcinoembryonic antigen measurement, abdominal contrast-enhanced computed tomography, and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of colorectal cancer recurrence: a correlative study

Introduction The aim of this study was to evaluate the correlative role of fluorine-18 fluorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) in carcinoembryonic antigen (CEA) measurement and contrast-enhanced abdominal computed tomography (ceCT) in the detection of colorectal cancer (CRC) recurrence. Materials and methods A total of 96 patients (40 female, 56 male; mean age, 60.6 +/- 12 years) with a previous diagnosis of CRC underwent F-18-FDG PET/CT on suspicion of recurrence and were evaluated retrospectively. Inclusion criteria were accepted as the presence of increased serum CEA levels or positive findings on abdominal ceCT or both. F-18-FDG PET/CT findings were compared with histopathological findings and/or clinical follow-up data as the gold standard. Patients were divided into three groups: group 1, with increased CEA levels and normal abdominal ceCT; group 2, with normal CEA levels and positive ceCT; and group 3, with increased CEA levels and positive ceCT. Results Whereas sensitivities of CEA, ceCT, and F-18-FDG PET/CT in the three patient groups were calculated as 91, 67, and 96%, specificities were 13, 51, and 62%, respectively. There were 35, 14, and 46 patients in groups 1, 2, and 3, respectively. In separate analyses conducted on the groups, sensitivity of F-18-FDG PET/CT was computed as 100 and 100% and specificity as 88 and 80% for groups 1 and 2. In group 3, which comprised four patients with secondary malignancies, sensitivity and specificity of F-18-FDG PET/CT were 94 and 16%, respectively. Conclusion F-18-FDG PET/CT has an additional role in the detection of CRC recurrence with a higher sensitivity compared with CEA and ceCT alone, and F-18-FDG PET/CT is especially more successful in patients with isolated elevated CEA levels or positive ceCT findings without accompanying CEA elevation. Nucl Med Commun 33:990-994 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.