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

Abstract

PurposeColorectal cancer is the third most common cancer in France while any age or sex. In 60 to 80% of cases, colorectal adenocarcinoma was developed from precancerous lesions, usually adenomatous. Screening allows early action limit the risk of metastatic cancer lesions. The aim of this study was to consolidate the importance to realize a colonoscopy in front of a colorectal focal uptake PET-CT. We would also try to show a correlation between the histology and SUVmax value. Materials and methodsThis is a retrospective study from January 2010 to November 2012, bi-centric, involving 123 patients. All patients underwent PET-CT and colonoscopy next. During this period, about 6756 PET-CT realized, only 388 patients had PET-CT and colonoscopy. Patients have been included when PET-CT was before colonoscopy, and had no known colorectal cancer. ResultsOut of 123 patients, we observed 136 suspect fixed focal uptake, among which 119 (87.5%) corresponded to 85 “polyps” (51 adenomas low grades, 16 hyperplastic polyps, 8 high-grade adenomas and 10 adenocarcinomas), 28 inflammatory, 5 metastasis, 1 lymphoma and 17 false positives. A statistically significant difference (P<0.001) was found between the adenocarcinomas SUVmax and the low-grade adenomas SUVmax. It also remained significant between groups recomposed with adenocarcinomas and high-grade adenomas vs. low-grade adenomas and hyperplastic polyps (P<0.001). It is found that 97.7% of lesions with a SUVmax greater than 10 were either adenocarcinoma or high-grade adenomas. ConclusionThis study confirms the importance of realizing a colonoscopy to explore an incidental focal colorectal 18F-fluorodeoxyglucose uptake. It also shows promising results to the SUVmax value for guide us on the histological severity and the urgency to make a colonoscopy.