Positive Incidental Colorectal PET/CT: Sometimes Serious Lesions, Sometimes Not
Douglas K. Rex, MD, MASGE, reviewing Kousgaard S, et al. Endosc Int Open 2020 Dec.
There is general agreement that when positron emission tomography (PET) incidentally lights up the colon, there is a substantial positive predictive value for cancer and large adenomas.
The current study is significant primarily for its large size. In the retrospective study from the North Denmark Region, 19,987 patients underwent 18F-fluorodeoxyglucose-PET/CT from 2006 through 2015, of whom 1,652 had a colonoscopy within 12 months. Incidental colorectal uptake was noted in 623 patients, of whom 74 were excluded, mostly for prior or current known colon cancer (n=68).
Of the remaining patients, cancer was present in 13.8% and adenoma in 40.3%. The overall positive predictive value for neoplasia was 72%, and the sensitivity for any neoplasia was 57%.
Ninety-two patients with a PET-avid lesion had a negative colonoscopy; none of these patients developed colorectal cancer during a median follow-up of 7.2 years.
COMMENTAlthough this study was large, major deficiencies with it were not matching lesions by location and not describing the adenomas by size.
In any case, these data indicate that a positive incidental PET/CT in the colon does indeed have a significant positive predictive value; however, colonoscopists should not be too concerned when no lesion is found because this occurs often.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
CITATION(S)
Kousgaard SJ, Gade M, Petersen LJ, Thorlacius-Ussing O. Incidental detection of colorectal lesions on 18F-FDG-PET/CT is associated with high proportion of malignancy: a study in 549 patients. Endosc Int Open 2020;08:E1725-E173. (https://doi.org/10.1055/a-1266-3308)
