Is systematic colonoscopy of incidental colonic uptakes detected by 18F-FDG PET/CT safe and always indicated?

Objectives As 18F-FDG-PET/CT is increasingly used, incidental uptake detected by this imaging method is also increasing. The aim of this study was to assess the interest and potential risks of achieving a systematic colonoscopy to explore colonic uptakes detected by 18F-FDG PET/CT.

Methods Records of 8416 patients who underwent an ¹⁸F-FDG-PET/CT from January 2005 to May 2014 in our institution were retrospectively reviewed. Patients with colonoscopy suggested on the report and realized within 6 months were included. Characteristics of colonic uptake were evaluated (localization, focal or diffuse pattern, SUVmax…). Results of colonoscopy (biopsy, histopathological analysis) and potential serious adverse events were collected.

Results A colonoscopy was suggested for 230 patients of the 8416 patients (2.7%) but only 94 had a colonoscopy within 6 months after the examination. There were 18 (21,7%) malignant lesions, 37 (44,6%) premalignant lesions, 28 (33,7%) non-neoplastic lesions. None of the diffuse uptake corresponded to premalignant or neoplastic lesion. There was no stastistically significant difference of mean SUVmax between malignant, premalignant and non-neoplastic lesions. 1 major complication (colonic perforation) occurred. The rate of major complication is 1,2% in this study.

Conclusions Presence of a focal colonic uptake justifies a colonoscopy to detect malignant/premalignant lesions. Due to the very low risk of neoplastic lesion, diffuse uptake should not be explored. Risk-benefit balance of colonoscopy should be weighted, particularly among older patients.

Research Support None