Cancer imaging : the official publication of the International Cancer Imaging Society

Diagnostic value of (18)F-FDG PET/CT as first choice in the detection of recurrent colorectal cancer due to rising CEA.

PMID 26263901


The diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) as the first imaging approach in the evaluation of rising carcinoembryonic antigen (CEA) is not clear. The objective of this study was to investigate the value of (18)F-FDG PET/CT in patients with colorectal cancer (CRC) and suspected recurrence based on rising CEA. A total of 73 patients with CRC were referred to PET/CT after radical surgery. Generally, all patients were scheduled to follow a CT-based post-surgical follow-up regimen. In the case of rising CEA, (18)F-FDG PET/CT was performed in most patients with contrast-enhanced CT. The PET/CT images were independently reviewed by two readers. The presence or absence of recurrence was based on histology and/or standardized clinical follow-up. Among 35 patients who had confirmed recurrence of CRC, PET/CT demonstrated recurrence with a sensitivity of 85.7xa0%, a specificity of 94.7xa0%, a positive predictive value of 93.8xa0%, and a negative predictive value of 87.8xa0%. The SUVmax ranged from 1.3 to 19.9. The mean time since the last postoperative imaging and PET/CT was 8xa0months (median 4xa0months). CEA values at referral ranged from 1.5 to 164.0xa0μg/L (median 5.6xa0μg/L). The diagnostic properties of PET/CT were analyzed in subgroups of patients with a single rising CEA sample (30 patients, 41xa0%), 31 patients (43xa0%) with two or more consecutive increases, and 12 patients (16xa0%) with persistently elevated values. (18)F-FDG PET/contrast-enhanced CT has high diagnostic accuracy in the diagnosis of recurrent CRC, even in patients in a conventional CT-based follow-up program.