Prevalence and malignancy risk of focal colorectal incidental uptake detected by ¹⁸F-FDG-PET or PET/CT: a meta-analysis

Abstract

BackgroundThe aim of the study was to meta-analyze published data about prevalence and malignancy risk of focal colorectal incidentalomas (FCIs) detected by Fluorine-18-Fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography (18F-FDG-PET or PET/CT).MethodsA comprehensive computer literature search of studies published through July 31st 2012 regarding FCIs detected by 18F-FDG-PET or PET/CT was performed. Pooled prevalence of patients with FCIs and risk of malignant or premalignant FCIs after colonoscopy or histopathology verification were calculated. Furthermore, separate calculations for geographic areas were performed. Finally, average standardized uptake values (SUV) in malignant, premalignant and benign FCIs were reported.ResultsThirty-two studies comprising 89,061 patients evaluated by 18F-FDG-PET or PET/CT were included. The pooled prevalence of FCIs detected by 18F-FDG-PET or PET/CT was 3.6% (95% confidence interval [95% CI]: 2.6–4.7%). Overall, 1,044 FCIs detected by 18F-FDG-PET or PET/CT underwent colonoscopy or histopathology evaluation. Pooled risk of malignant or premalignant lesions was 68% (95% CI: 60–75%). Risk of malignant and premalignant FCIs in Asia-Oceania was lower compared to that of Europe and America. A significant overlap in average SUV was found between malignant, premalignant and benign FCIs.ConclusionsFCIs are observed in a not negligible number of patients who undergo 18F-FDG-PET or PET/CT studies with a high risk of malignant or premalignant lesions. SUV is not reliable as a tool to differentiate between malignant, premalignant and benign FCIs. Further investigation is warranted whenever FCIs are detected by 18F-FDG-PET or PET/CT.

Limited Identification of Dual-time-point Positron Emission Tomography/Computed Tomography in Advanced Colorectal Neoplasms

“…However, a high SUVmax may also be found in various benign conditions because 18 FDG is not a neoplasm-specific substance. Indeed, Treglia et al ( 20 ) showed that the SUVmax alone should not be used to differentiate between a malignant, premalignant and benign incidental colonic focal uptake because a significant overlap of the SUVmax was found between these groups. Our results are similar to those of their report in this point, although our data clearly demonstrate that advanced neoplasms had a significantly higher mean SUVmax, compared with that in non-advanced lesions.…”

Detection of incidental colorectal pathology on positron emission tomography/computed tomography

“…With its increasing availability and use in cancer patients, it is not uncommon to detect incidental 18 F‐FDG uptake on PET/CT in sites other than where the primary cancer is known or suspected, posing a diagnostic challenge to clinicians. A common site is the large bowel, where the prevalence of incidental focal colorectal 18 F‐FDG uptake detected by PET or PET/CT is estimated at 3.6% . While diffuse and segmental patterns of 18 F‐FDG uptake are attributed to benign or inflammatory causes, focal uptake is associated with a significant risk of neoplasia .…”

“…A common site is the large bowel, where the prevalence of incidental focal colorectal 18 F-FDG uptake detected by PET or PET/CT is estimated at 3.6%. 3 While diffuse and segmental patterns of 18 F-FDG uptake are attributed to benign or inflammatory causes, focal uptake is associated with a significant risk of neoplasia. [4][5][6][7][8][9][10][11] Given that colorectal cancer may be insidious in onset and run a silent course until late, these radiological findings should not be ignored.…”

Fixations colorectales focales en TEP/TDM 18FDG : importance de la coloscopie et apport du SUVmax pour orienter sur la gravité anatomopathologique des lésions

“…En particulier, les méthodes de reconstruction sont identiques permettant d'homogénéiser les images et les valeurs de SUVmax. Dans la méta-analyse de Treglia et al de 2014 [28], ils n'ont pas pu définir de valeur de SUVmax en fonction de la nature histologique des lésions à cause de la disparité des caméras TEP/TDM. Un projet d'uniformité des paramètres d'injection, d'acquisition et de reconstruction devrait voir le jour dans les années qui viennent mais, en attendant, de grosses disparités existent sur le territoire français.…”