BACKGROUND/AIMS Although access to [18F]2-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography and computed axial tomography (PET/CT) for patients with malignancy has increased, little information is available on the suitability of PET/CT for diagnosis of advanced colonic neoplasms in oncology patients and on the clinical significance of incidental 18F-FDG focal uptake confined to the left-sided colon.

METHODS Patients who underwent 18F-FDG PET/CT followed, within 90 days, by colonoscopy were identified. Case-control analysis was undertaken to determine whether focal 18F-FDG uptake confined to the left-sided colon was associated with advanced neoplasms in the right-sided colon.

RESULTS One hundred ninety-five patients with colonic 18F-FDG uptake and 561 without colonic (18)F-FDG uptake were identified. Of the 195 patients with focal colonic 18F-FDG activity, 103 patients (52.8%) had 145 advanced colonic neoplasms, including 58 colon cancers and 11 metastatic cancers. In the detection of advanced colonic neoplasms, the sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were 54.4, 82.4, 46.9, and 86.3%, respectively. Overall accuracy was 76.2%. Ten (8.0%) of the 125 patients with focal 18F-FDG uptake confined to the left-sided colon had three colon cancers and seven advanced adenomas in the right-sided colon. Case-control analysis revealed that focal 18F-FDG uptake confined to the left-sided colon was associated with an advanced neoplasms in the right-sided colon (OR, 3.02; 95% CI, 1.12-8.13; P = 0.023).

CONCLUSIONS Colonic focal (18)F-FDG uptake by oncology patients warrants endoscopic verification. Complete colon evaluation by colonoscopy is required, even for patients with focal 18F-FDG uptake confined to the left-sided colon.