The value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in asymptomatic examinees with unexplained elevated blood carcinoembryonic antigen levels.

Abstract

Cancer is still a clinical challenge, with many efforts invested in order to achieve timely detection. Unexplained elevated blood carcinoembryonic antigen levels are occasionally observed in an asymptomatic population and considered as a risk factor of cancers. The purpose of this study was to determine the validity of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) for detecting cancer in an asymptomatic population with an unexplained elevation in blood carcinoembryonic antigen (CEA) levels. This retrospective study included a total of 1920 asymptomatic examinees conducted from August 2011 through September 2013. The participants underwent CEA assay and conventional medical imaging (CEA-conventional), or CEA assay and F-18 FDG-PET/CT (CEA-PET/CT). The validity of conventional medical imaging and CEA-PET/CT scanning for detecting cancer and early-stage cancer in an asymptomatic population with an unexplained elevation in blood CEA levels were evaluated. Sensitivity, specificity, cancer detection rate, missed cancer detection rate, early-stage cancer detection rate, and early-stage cancer ratio using the CEA-PET/CT scanning were 96.6%, 100%, 10.4%, 0.4%, 3.7%, and 34.5%, respectively. In contrast, the corresponding values obtained using the conventional medical imaging were 50.6% (P < 0.0001), 100% (P > 0.9999), 50.6% (P < 0.0001), 99.9% (P = 0.055), 2.6% (P < 0.0001), 2.5% (P = 0.04), 0.7% (P = 0.0004), and 14.5% (P = 0.002), respectively. The F-18 FDG-PET/CT scanning significantly improved the validity of the cancer detection program in the asymptomatic population with an unexplained elevation in CEA levels.