Application and Indication of Carcinoembryonic Antigen Triggered 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scanning in the Detection of Relapse of Colorectal Cancer Patients After Curative Therapy.

OBJECTIVE: This study aimed to explore the characteristics of patients with colorectal cancer (CRC) following curative therapy that may benefit from fluorine-18-2-uoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT) scanning, evaluate the application of carcinoembryonic antigen (CEA)-triggered F-FDG PET/CT scanning, and provide referential indicators.

METHODS: This retrospective study included 56 CRC patients who received a PET/CT scan as a primary examination because of rising CEA levels after curative therapy and who had not received any other radiological examinations previously.

RESULTS: The rate of recurrence or metastasis was 75.0% by PET/CT scan but was 69.6% with follow-up treatment. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 94.9%, 70.6%, 87.5%, 88.1%, and 85.7%, respectively. TNM (tumor, node, metastasis) stage, body mass index, and CEA level were significant prognostic factors.

CONCLUSIONS: Positron emission tomography/CT can be selectively applied as a primary examination in CRC patients with asymptomatic elevation of CEA. High CEA levels, increased body mass index, and advanced TNM staging are risk factors for relapse.