Negative Colonoscopy for FIT-Positive Patients: Should We Keep Doing FIT?
Douglas K. Rex, MD, MASGE, reviewing Peng SM, et al. Gut 2020 Sep 28.
In this study from Taiwan, patients with a negative colonoscopy after a positive fecal immunochemical test (FIT) during the interval 2004 through 2009 were followed until the end of 2014. Some patients received subsequent FIT after colonoscopy and some did not. The incidence of colorectal cancer was 1.34 per 1000 person-years of observation in those who received subsequent FIT and 2.69 in those who did not. Higher fecal hemoglobin concentration was associated with increased risk. Compared to the group with fecal hemoglobin of 20 to 39, the risk of incident cancer was 1.93 for fecal hemoglobin of 40 to 59, 2.26 for fecal hemoglobin of 100 to 149, and 2.44 for fecal hemoglobin of 150 or higher.
A low adenoma detection rate (ADR) predicted interval cancer risk in univariate analyses but not multivariate analysis.
COMMENTThis is not the first study to find that FIT can have significant value after a negative colonoscopy. FIT essentially compensates for missed lesions. The value is greater for indications associated with a higher prevalence of disease because these same factors are associated with a greater chance of missed lesions. Thus, the use of FIT after negative colonoscopy can be appropriate when either the ADR of the physician is low or the pretest probability of disease is high (indications associated with high prevalence). Unfortunately, in the United States, FIT results are reported only as positive or negative rather than giving the actual amount of hemoglobin detected, so higher hemoglobin amounts cannot be used to stratify patient need for continued FIT testing.
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)
Peng SM, Hsu WF, Wang YW, et al. Faecal immunochemical test after negative colonoscopy may reduce the risk of incident colorectal cancer in a population-based screening programme. Gut 2020 Sep 28. (Epub ahead of print) (http://doi.org/10.1136/gutjnl-2020-320761)
