A. S. M. Abdul Fattah

A cost-effective analysis of the optimum number of stool specimens collected for immunochemical occult blood screening for colorectal cancer

This study was carried out to assess, from the viewpoint of cost-effectiveness, the optimum number of faecal specimens to collect for use in immunochemical occult blood testing as a means of screening for colorectal cancer. 3300 asymptomatic individuals were subjects of this study. They gave samples for an immunochemical faecal occult blood test, monohaem and colonoscopy was carried out during a medical check-up. For evaluation of the optimum number of sampling specimens, the results of the first day of sampling, those of the first and second days, and those of samples taken for 3 consecutive days were considered as the single-day method, the 2-day method and the 3-day method respectively. The average cost to detect 1 patient with colorectal cancer, the detection rate and the false-positive rate of these three faecal sample collection methods were evaluated. The average costs for one cancer case detected were calculated as

Validity of Immunological Faecal Occult Blood Screening for Colorectal Cancer: A Follow up Study

3,630.68 for the single-day method,

Does stool collection method affect outcomes in immunochemical fecal occult blood testing

3,350.65 for the 2-day method and

Colorectal cancer in iron deficiency anemia with a positive result on immunochemical fecal occult blood.

4,136.36 for the 3-day method, respectively. The detection rate and the false-positive rate were calculated as 47 and 3.5% for the single-day method, 82 and 4.7% for the 2-day method and 88 and 5.3% for the 3-day method, respectively. This detection rate was significantly different between the single- and the 2-day methods, as well as between the single- and the 3-day methods (P<0. 05). No significant differences in the false-positive rate amongst the three testing methods were observed. This analysis suggests that a 2-day faecal collection method is recommended for immunochemical occult blood screening by Monohaem from the aspects of cost-effectiveness and diagnostic accuracy.

Diagnostic accuracy of immunochemical faecal occult blood test for gastric cancer

Objectives – Immunological faecal occult blood testing has been recognised as a useful method for wide scale screening of colorectal cancer in Japan during the past few years. This study was carried out to evaluate the validity of an immunological faecal occult blood test for colorectal cancer screening. Methods – A screening programme for colorectal cancer using an immunological faecal occult blood test was conducted on 3365 residents of regions within Nagano prefecture in 1991, and all the subjects were followed up for three years by verification from cancer registration. Based on the incidence of false negative cases among those who had been evaluated as normal by this screening, but were diagnosed as having colorectal cancer, the sensitivity and the specificity of this test were estimated. Results – Four false negative cases were found during the subsequent three year follow up period after screening. Among these four cases, one case was within the first follow up year, one case within the — second year, and two cases within the third year. Accordingly, the sensitivity of this test was calculated as 90.9% within one year, 83.3% within two years, and 71.4% within three years, while the specificity was found to be 95.6%, indicating a validity higher than that achieved by a chemical occult blood test. Conclusion – These findings suggest that the immunological faecal occult blood test has a high diagnostic accuracy and is a useful strategy for colorectal cancer screening.

Family history of colorectal adenomatous polyps as a risk factor for colorectal cancer

PURPOSE: This paper compares the positive predictive value of an immunochemical fecal occult blood test for colorectal neoplasms between the stool specimens obtained during the digital rectal examination and those obtained during the routine screening. METHODS: In a medical check-up, 1,688 subjects received both an immunochemical fecal occult blood test and a colonoscopy. Fecal occult blood was tested by two methods: digital rectal examination and routine screening. The positivity rate of an immunochemical fecal occult blood test and the positive predictive value for colorectal cancer and large adenomatous polyp were determined by these two methods. RESULTS: The positivity rate and the positive predictive value were 5.4 percent and 19.8 percent (4.4 percent for cancer and 15.4 percent for adenomatous polyp) in the digital rectal examination method and 3.5 percent and 27.1 percent (6.8 percent for cancer and 20.3 percent for adenomatous polyp) in the routine screening method, respectively. These figures indicate a significant difference in the positivity rate (P<0.01) and the positive predictive value (P<0.05) between these two methods. CONCLUSIONS: These findings indicate that the stool obtained by routine screening has a better positive predictive value than stool collected during the digital rectal examination.

Immunochemical Fecal Occult Blood Test Is Not Suitable for Diagnosis of Hemorrhoids

Abstract. We examined the relationships between iron deficiency anemia, immunochemical fecal occult blood test results, and colorectal cancer. Samples were collected from 17,664 asymptomatic individuals for an immunochemical occult blood test, and colonoscopy was carried out during medical check-up. The positivity rate on the occult blood test and detection rate for colorectal cancer were compared in those with and those without iron deficiency anemia. In addition, the detection rate for colorectal cancer was determined in four groups stratified by occult blood test results and the presence of iron deficiency anemia. The occult blood test was positive in 18.4% of those with and in 3.8% of those without iron deficiency anemia (P<0.001), and colorectal cancer was detected in 2.7% of those with and in 0.4% of those without iron deficiency anemia (P<0.05). The highest rate of colorectal cancer was found in subjects with both iron deficiency anemia and positive occult blood test result. These findings indicate positive associations between iron deficiency anemia and immunochemical occult blood test results, and between iron deficiency anemia and colorectal cancer. Colonoscopy is thus necessary particularly in cases of positive immunochemical occult blood test result and iron deficiency anemia.

Detection rate of immunochemical fecal occult blood test for colorectal adenomatous polyps with severe dysplasia.

Objectives –Toinvestigate the accuracy of the immunochemical occult blood test in screening for gastric cancer and to evaluate whether or not the upper digestive tract should be examined when the occult blood test is positive but there is no abnormal sign in the colorectum. Methods –In a case-control study an occult blood test was carried out on 150 subjects with gastric cancer, ISO subjects with colorectal cancer, and on 300 healthy subjects. Data were analysed from 44 996 persons attending a population screening programme who underwent both radiological gastric cancer screening (barium meal) and colorectal cancer examination by occult blood test. Results –In the case—control study the occult blood test was positive in 27/150 (18%) subjects with gastric cancer, in 112/150 (75%) subjects with colorectal cancer, and in 24/300 (8%) healthy controls. In the population screening programme the occult blood test was positive in 4/50 (8%) persons with gastric cancer and 3232/44 950 (7%) persons without gastric cancer,- indicating no difference between them. Conclusions –These data show that the immunochemical faecal occult blood test is worthless as a screening test for gastric cancer, and that examination of the upper digestive tract is unnecessary in cases where the faecal occult blood test is positive but there is no sign of colorectal disease.

Relationship between fecal sampling times and sensitivity and specificity of immunochemical fecal occult blood tests for colorectal cancer

The aim of this study was to evaluate the risk of common colorectal cancer among first-degree relatives of patients with colorectal adenomatous polyps. In a population screening programme, 59406 subjects underwent an immunochemical faecal occult blood test. In a medical check-up-based cross-sectional study, 6139 subjects had a colonoscopic examination. They were divided into two groups, according to the results of a questionnaire on family history of colorectal adenomatous polyps, and the detection rates for colorectal cancer were compared in the groups positive or negative for a family history of colorectal adenomatous polyps. In the screening programme-based cross-sectional study, the detection rate for colorectal cancer was 0.57% (95% confidence interval (CI): 0.38-0.76) and 0.15% (95% CI: 0.12-0.18) in subjects with and without a family history of colorectal adenomatous polyps, respectively, showing a significant difference in the detection rate for colorectal cancer between the two groups (P<0.05). In the medical check-up-based cross-sectional study, the detection rate for colorectal cancer was 2.31% (95% CI: 1.15-3.47) and 0.53% (95% CI: 0. 34-0.72) in subjects with and without a family history of colorectal adenomatous polyps, respectively, indicating a significant difference between the two groups (P<0.05). These findings indicate that first-degree relatives of patients with colorectal adenomatous polyps have an elevated risk for common colorectal cancer, and that people with a family history of colorectal adenomatous polyps should be considered as a priority group for colorectal cancer screening.

Characteristics of colorectal cancer with false negative result on immunochemical faecal occult blood test.

PURPOSE This study was conducted to clarify the diagnostic value of an immunochemical fecal occult blood test for hemorrhoids. PATIENTS AND METHODS In a case-control study, an immunochemical fecal occult blood test with a 2-day method was carried out on 82 subjects with hemorrhoids, on 82 subjects with colorectal cancer, and on 82 healthy subjects. In a population-based cross-sectional study, 29,714 subjects who received an immunochemical occult blood screening with a 2-day method were divided into two groups, according to the results of a questionnaire on hemorrhoids, and the positivity rate of an immunochemical test as well as the predictive value for colorectal cancer were compared in the two groups. Moreover, both an immunochemical occult blood test with a 2-day method and colonoscopy were conducted at the same time on asymptomatic subjects during a medical checkup. RESULTS In the case-control study, the test was positive in 13.4% subjects with hemorrhoids, in 84.1% subjects with colorectal cancer, and in 4.9% healthy subjects, respectively, showing a significant difference in the detection rate between the two diseases (P < 0.001). In the population screening program, the test was positive in 6.9% subjects with hemorrhoids and in 6.5% subjects without hemorrhoids, and the predictive value was 3.2% in subjects with and without hemorrhoids, respectively, indicating no significant difference in the positivity rate as well as the predictive value between the two groups. Among 232 subjects in a medical checkup, 28 patients with hemorrhoids and 21 patients with colorectal polyp 1 cm or larger were diagnosed by colonoscopy, and the occult blood test was positive in 16.7% patients with hemorrhoids and in 52.4% patients with colorectal polyp, respectively. There was a significant difference in the sensitivity between the two disease groups (P < 0.05). CONCLUSIONS These findings indicate that the immunochemical fecal occult blood is unsuitable for the diagnosis of the patients with hemorrhoids and an examination of the colorectum is necessary in cases where the occult blood test is positive but there is a sign of hemorrhoids.