[The effect of immunofecal occult blood test on colorectal cancer screening]

To discuss the clinical value of immunofecal occult blood test in screening of colorectal cancer and its precancerous lesions in a large series of health checkup population.

Colorectal cancer and its precancerous lesions in 5919 subjects undergoing health checkup in our hospital were screened out by using immunofecal occult blood test from July 2006 to June 2007; positive cases with the test were subjected to colorectal endoscopy or X-ray barium enema examination. Relevant results were analyzed in combination with clinical and pathological data.

Positive result was obtained in 314 out of the 5919 subjects undergoing health checkup with immunofecal occult blood test; the positive rate was 5.30%. 241 cases (76.75%) of them accepted colorectal endoscopic examination and 23 cases (7.32%) accepted X-ray barium enema examination. The total follow up rate was 84.08% with 50 cases out of contact. After excluding the cases out of contact, 16 cases of colorectal cancer were found morbidity 2.37 per thousand including 8 (50.00%) cases of Dukes A, 7 cases (43.75%) of Dukes B and 1 case of Dukes C (6.25%). The detection rate of colorectal cancer with positive immunofecal occult blood test was 6.06% (16/264). 94 cases (16.01 per thousand) of adenomatous polyps were found including 55 cases (58.51%) of tubular adenoma, 23 cases (24.47%) of villiform-tubular adenoma and 16 cases (17.02%) of villiform adenoma. Among these cases 55 (58.51%) were solitary and 39 (41.49%) multiple. In addition, 6 cases of ulcerative colitis in active phase were found. Altogether 116 (43.94%) of the 264 cases with positive immunofecal blood test and not out of contact were found to have colorectal cancer or its precancerous lesions.

Immunofecal occult blood test is suitable for screening of colorectal cancer and its precancerous lesions in large series of population. Colorectal cancer and its precancerous lesions may be found in relatively early phase and be eradicated in curable stage, thus to reduce the morbidity and mortality.