Colorectal adenomatous polyps detected by immunochemical occult blood screening.
OBJECTIVE
This study aimed to evaluate the validity of immuno-chemical occult blood screening for colorectal adenomas and to clarify the characteristics of this disease which are detected.


METHODS
We studied 140 colorectal adenomas and 140 healthy controls in a hospital based case control study, in which three-day testing was conducted to assess the accuracy of the immuno-chemical occult blood screening test (total 280 patients). A further 80 colorectal adenomas 1 cm or larger, which were detected by a screening program, were compared with matched cases detected by the outpatient clinics (total 160 patients). A comparison of characteristics including tumor location, shape and histology was made between the two groups.


RESULTS
Sensitivity and specificity were calculated to be 46% (61% for tumors larger than 1 cm, 30% for those less than 1 cm), and 96% respectively, showing a significant difference in sensitivity between large and small adenomas (p < 0.01). The proportion of rectal adenomas was significantly higher in the outpatient clinics (41%) than in the screening program (21%) (p < 0.05), whereas no differences were noted in the other measures.


CONCLUSIONS
These results suggest that immuno-chemical occult blood is inadequate as a screening test for detecting small adenomas, as t can not differentiate between the detection of rectal adenomas from large adenomatous polyps.
Fattah
A S
AS
Department of Public Health, Shinshu University School of Medicine, Nagano, Japan.
Nakama
H
H
Kamijo
N
N
Fujimori
K
K
Zhang
B
B
D000328:Adult; D016022:Case-Control Studies; D003111:Colonic Polyps / Q000097:blood / Q000175:diagnosis*; D015179:Colorectal Neoplasms / Q000097:blood / Q000175:diagnosis*; D005069:Evaluation Studies as Topic; D006801:Humans; D008403:Mass Screening; D009780:Occult Blood; D012680:Sensitivity and Specificity