A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population.
OBJECTIVE
The fecal occult blood test (FOBT) is recommended as a screening test for colorectal cancer, but there are few reliable studies on the accuracy of immunochemical FOBT. The aim of this study was to analyze the sensitivity of immunochemical FOBT and to compare the results with the findings from complete colonoscopy.


METHODS
Asymptomatic adults underwent 1-time immunochemical FOBT and total colonoscopy simultaneously. The prevalence and location of colorectal neoplasia were determined by colonoscopy. The results of immunochemical FOBT and the colonoscopic findings were compared.


RESULTS
Of 21,805 patients, immunochemical FOBT was positive in 1231 cases (5.6%). The sensitivity of 1-time immunochemical FOBT for detecting advanced neoplasia and invasive cancer was 27.1% and 65.8%, respectively. In addition, the sensitivity for invasive cancer according to Dukes' stage showed 50.0% for Dukes' stage A, 70.0% for Dukes' stage B, and 78.3% for Dukes' stages C or D. The sensitivity for detecting advanced neoplasia at the proximal colon was significantly lower than that detected in the distal colon (16.3% vs 30.7%, P = .00007).


CONCLUSIONS
Although the screening of asymptomatic patients with immunochemical FOBT can identify patients with colorectal neoplasia to a certain extent, the sensitivity is relatively low and different according to the tumor location. Therefore, programmatic and repeated screening by immunochemical FOBT may be necessary to increase sensitivity for colorectal cancer detection.
Morikawa
Tamiya
T
Department of Medicine and Medical Science, Okayama University Graduate School of Medicine and Dentistry, Japan.
Kato
Jun
J
Yamaji
Yutaka
Y
Wada
Ryoichi
R
Mitsushima
Toru
T
Shiratori
Yasushi
Y
D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000517:prevention & control*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009780:Occult Blood; D011159:Population Surveillance; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity