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Physician recommendations for follow-up of positive fecal occult blood tests.

Following a positive fecal occult blood test (FOBT), physician recommendation of complete diagnostic evaluation (CDE) is an important first step to ensure identification and treatment of preinvasive or invasive colorectal cancer. Physicians may not recommend CDE, however, potentially compromising the effectiveness of colorectal cancer screening programs and the quality of care for individual patients. The authors used a theoretical model of health behavior and two national physician samples to explore factors associated with recommendations for CDE. Overall, 63 percent of the sample of physicians providing primary care and 76 percent of the gastroenterologist and general surgeon sample reported recommending CDE. Variables representing the theoretical model constructs of physician background, experience, and practice patterns; practice environment; physician psychosocial representations; and patient characteristics were significantly associated with recommendations of CDE. Development of interventions to improve recommendations of CDE is an important area for future research.

Colorectal Neoplasms↗

Characteristics of colorectal cancer that produce positive immunochemical occult blood test results on stool obtained by digital rectal examination.

OBJECTIVE: To clarify the clinicopathological features of colorectal cancer that show positive results on an immunochemical fecal occult blood test of stool obtained by digital rectal examination. METHODS: In a cross-sectional study, 9952 subjects received both an immunochemical fecal occult blood test of stool obtained by digital rectal examination and colonoscopy annually over a nine-year period of medical checkups; 64 patients with colorectal cancer were identified. The study subjects comprised 39 patients with colorectal cancer who had positive results (positive group) and 25 patients with colorectal cancer who had negative results (negative group) on an immunochemical fecal occult blood test of stool obtained by digital rectal examination. The positive and negative groups were compared in terms of their individual factors, such as site, size, Dukes classification and histological type of the cancer lesions. RESULTS: The prevalence of rectal cancers was higher in the positive group than in the negative group (P<0.05), but there were no differences between the two groups with respect to any other factors. CONCLUSIONS: These findings indicate that stool obtained during the digital rectal examination is unsuitable for detecting fecal occult blood, especially for the detection of proximal colon neoplasms.

Adenocarcinoma↗

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

OBJECTIVES: A comparative study was carried out to clarify the clinicopathological features of colorectal cancer diagnosed after a false negative result on the immunochemical faecal occult blood test. METHODS: 236 patients with colorectal cancer were studied: 48 patients with negative results and 188 patients with positive results with the faecal occult blood test. The two groups were compared according to their age and sex and by the site, size, macroscopic type, Dukes's classification, and histological type of their cancer lesions. Additionally, the above factors were investigated prospectively and compared in 40 cases of colorectal cancer cases diagnosed as false negative and in matched cases diagnosed as true positive in cancer screening by the immunochemical faecal occult blood test. RESULTS: In both the hospital based case-control study and the screening programme based nested case-control study the prevalence of rectal cancers was higher in the false negative group than in the true positive group (P = 0.02, P = 0.03), but there were no differences between the two groups for any other factors. CONCLUSION: These results suggest that the immunochemical faecal occult blood test is unsuitable for the diagnosis of rectal cancer.

Case-Control Studies↗

Physician-reported reasons for limited follow-up of patients with a positive fecal occult blood test screening result.

OBJECTIVE: Fecal occult blood testing (FOBT) screening can reduce colorectal cancer (CRC) mortality when patients with an abnormal result [FOBT(+)] undergo a complete diagnostic evaluation (colonoscopy or double-contrast barium enema with or without flexible sigmoidoscopy). The aim of this study was to determine common reasons for nonperformance of a complete diagnostic evaluation. METHODS: We identified 544 FOBT(+) patients, aged 50 yr or older, who had participated in a managed care organization-sponsored CRC screening program. The performance of a complete diagnostic evaluation was determined from a patient-specific follow-up form and managed care organization claims data. Physicians were asked to report whether patients submitted to a complete diagnostic evaluation. When an evaluation was not done, the physicians were also asked to state the reasons for nonperformance. RESULTS: A total of 248 (46%) patients did not undergo a complete diagnostic evaluation. Physicians provided reasons for nonperformance for 50% (123/248). Factors accounting for nonperformance of a complete diagnostic evaluation were classified as follows: primary care physician decision (50%); specialist decision (28%); patient decision (17%); and other (practice-related) (5%). Many failures to complete an appropriate diagnostic evaluation were due to providers deciding to repeat the FOBT, perform a sigmoidoscopy, or not to proceed with any further testing. CONCLUSION: Many patients with a positive FOBT do not receive a complete diagnostic evaluation. The reasons for nonperformance most frequently have to do with physician decision making. Many physician-related explanations do not conform to expert recommendations for appropriate follow-up.

Aged↗

Performance characteristics and evaluation of an automated-developed and quantitative, immunochemical, fecal occult blood screening test.

OBJECTIVES: Guaiac fecal occult blood colorectal cancer (CRC) screening tests (FOBT) are faulted for low sensitivity and nonspecificity for human hemoglobin (Hb). Automated-developed, immunochemical, human Hb FOBT (I-FOBT) is specific, eliminates diet restrictions, and Hb quantification allows selection of a threshold for colonoscopy. Aims were to determine 1) test reproducibility; 2) test stability; 3) intrapatient daily I-FOBT variation; 4) test sensitivity and specificity for neoplasia in 500 symptomatic/high-risk patients undergoing colonoscopy; and 5) to correlate fecal Hb measurements with findings. METHODS: The desktop instrument OC-Sensor (Eiken, Japan) automatically develops and quantitates 50 tests/h for Hb. Patients prepared three tests, which were quantified and then 1) repeatedly re-examined; 2) stored at 4 degrees C or 20 degrees C or 28 degrees C and repeatedly examined; and 3) fecal Hb levels were correlated with colonoscopic findings. RESULTS: Five I-FOBTs re-examined five times in 1 day had no significant measurement changes. Thirty tests stored for 21 or more days had a decay/day of 0.3%+/- 0.4 at 4 degrees C (NS), 2.2%+/- 1.7 at 20 degrees C (NS), and 3.7%+/- 1.8 at 28 degrees C (p < 0.05). There were intrapatient variations between the three daily I-FOBTs (NS). At the recommended 100 ng Hb/mL threshold, all six cases of CRCs and 20 out of 28 cases of advanced adenomas were detected; evaluated together their sensitivity and specificity were 76.5% and 95.3%. CONCLUSIONS: Desktop, automated-developed, quantitative I-FOBT is now available. Refrigerated OC-Sensor samples are stable for 21 days, easy to prepare and develop and, at the 100 ng Hb/mL threshold, have high sensitivity, specificity, and negative predictive values for significant neoplasia. Suitability for population CRC screening awaits further evaluation.

Adenoma↗

Colorectal cancer screening in asymptomaic adults: comparison of colonoscopy, sigmoidoscopy and fecal occult blood tests.

BACKGROUND AND PURPOSE: Fecal occult blood tests (FOBT) and flexible sigmoidoscopy have previously been recommended for colon cancer screening. More recently, studies have recommended colonoscopy due to the high rates of advanced neoplasm not detected by FOBT and sigmoidoscopy. Previous studies of the effectiveness of colonoscopic screening in Taiwan were limited to families of patients with colorectal cancer. This study compared colonoscopy, sigmoidoscopy and FOBT for colorectal cancer screening in asymptomatic adults. METHODS: Screening colonoscopies and FOBT were performed in asymptomatic adults enrolled in our health-screening program between January 1997 and December 2000. Advanced neoplasm was defined as the presence of a polyp larger than 1 cm, polyps with villous or severe dysplastic features, or cancer. The junction of the splenic flexure and descending colon was defined as the boundary of the proximal and distal colon, and it was presumed that the distal colon would be examined using sigmoidoscopy in all patients. Data on the prevalence of polyps, advanced neoplasm, and cancer among different age groups were obtained. The results of chemical and immunologic FOBT were compared. The anatomic distributions of advanced neoplasm and cancer were analyzed. RESULTS: A total of 7,411 colonoscopic examinations were included in the analysis. Advanced neoplasms were present in 93 examinations (1.3%), including 16 cancers (0.2%). Chemical FOBT detected 20.2% of advanced neoplasms and 37.5% of cancers. Immunologic FOBT detected 48.3% of advanced neoplasms and 87.5% of cancers. If sigmoidoscopy had been performed in place of colonoscopy, 26.9% of advanced neoplasms and 12.5% of cancers would not have been detected. CONCLUSIONS: Colonoscopy can detect neoplastic lesions undetectable by FOBT and sigmoidoscopy in asymptomatic subjects. These results suggest that colonoscopy should be the method of choice in colon cancer screening.

Adult↗

A national survey of primary care physicians' methods for screening for fecal occult blood.

BACKGROUND: Screening with the fecal occult blood test (FOBT) has been shown to reduce colorectal cancer incidence and mortality in randomized, controlled trials. Although the test is simple, implementation requires adherence to specific techniques of testing and follow-up of abnormal results. OBJECTIVE: To examine how FOBT and follow-up are conducted in community practice across the United States. DESIGN: Cross-sectional national surveys of primary care physicians and the public. SETTING: The Survey of Colorectal Cancer Screening Practices in Health Care Organizations and the 2000 National Health Interview Survey. PARTICIPANTS: 1147 primary care physicians who ordered or performed FOBT and 11 365 adults 50 years of age or older who responded to questions about FOBT use. MEASUREMENTS: Self-reported data on details of FOBT implementation and follow-up of positive results. RESULTS: Although screening guidelines recommend home tests, 32.5% (95% CI, 29.8% to 35.3%) of physicians used only the less accurate method of single-sample in-office testing; another 41.2% (CI, 38.3% to 44.0%) used both types of test. Follow-up of positive test results showed considerable nonadherence to guidelines, with 29.7% (CI, 27.1% to 32.4%) of physicians recommending repeating FOBT. Furthermore, sigmoidoscopy, rather than total colon examination, was commonly recommended to work up abnormal findings. Nearly one third of adults who reported having FOBT said they had only an in-office test, and nearly one third of those who reported abnormal FOBT results reported no follow-up diagnostic procedures. LIMITATIONS: The study was based on self-reports. Data from the National Health Interview Survey may underestimate the prevalence of in-office testing and inadequate follow-up. CONCLUSIONS: Mortality reductions demonstrated with FOBT in clinical trials may not be realized in community practice because of the common use of in-office tests and inappropriate follow-up of positive results. Education of providers and system-level interventions are needed to improve the quality of screening implementation.

Colorectal Neoplasms↗

Inspection for gastric occult blood at regular intervals is the optimum program for the screening of esophageal-gastric cancer.

Gastric occult blood screening has been performed for 242296 persons from 1986 to 1993. 30227 persons had positive reactions to the occult blood reagent. Among them, 17915 persons were asked to accept gastroscopy exam, and 638 esophageal-gastric cancers were found. The cancer detection rates were 3.56%. 4774 persons were asked to accept screening twice and 203 persons were asked to accept screening three times. After follow-up, the cancer detection rates were 2.11% for occult blood positive group if the screening was conducted once a year. The missing case was 0.77% for negative group and it was 0.05% in the same group if the screening was performed twice. Lastly, the missing case would be decreased to 0% when the patients undergone the exam, for three times in continuity. Two thirds of patients still belonged to the early-middle stage of cancer. The 5-year survival rates were 95.2%. The missing case of cancer would be reduced to 0% if the screening was conducted for three years in continuity. The death rates were deducted as well. It is certified that this method is the most effective and reliable way for reducing the death rate of cancer and screening of the upper digestive tract cancer.

Adolescent↗

Colorectal cancer screening by fecal occult blood testing: results of a population-based experience.

AIMS AND BACKGROUND: The study evaluated the results of an experimental screening protocol for colorectal cancer by fecal occult blood testing in a municipality of the Province of Florence. METHODS: A total of 15,235 subjects aged 50-70 years were invited to perform a 1-day immunochemical fecal occult blood testing without any dietary restrictions. All eligible subjects were sent a personal invitation letter, followed by a postal reminder to non-responders. Subjects with a negative stool test were advised to repeat screening after 2 years. Subjects with a positive screening test were invited to undergo full colonoscopy or a combination of left colonoscopy and a double contrast barium enema. RESULTS: A total of 6,418 subjects performed the screening test, with an overall compliance of 42.1%. A total of 268 compliers had positive test results. The positivity rate was 4.2%. Detection rate for cancer and for adenomas was 5.1% and 11.6%, respectively. The positive predictive value was 14.3% for cancer and 32.5% for adenoma. A higher compliance was recorded in subjects born in the province of Florence or living in the centre of the town, in married subjects, and in women. The best results in compliance were associated with the direct distribution of fecal occult blood testing kits by general practitioners to their outpatients. CONCLUSIONS: The study provides useful information about the efficiency and feasibility of a screening program for colorectal cancer using fecal occult blood testing. Compliance results confirm the importance of GP involvement in oncological screening.

Aged↗

A simple strategy to improve patient adherence to outpatient fecal occult blood testing.

Poor patient adherence reduces the effectiveness of fecal occult blood testing for colon cancer. Patients at the inner-city clinic involved in the study have historically completed only one-third of the tests administered to them. The authors studied three ways of returning test kits (by hand, by mail, and by mail with prepaid postage). Among 146 randomly assigned patients, the completion rates were 37%, 57%, and 71%, respectively. The difference was significant between the first and third groups (p = 0.003), and the cost was less for the third group ($1.71 vs $2.24 per completed test). The authors recommend that clinics serving indigent populations use postage-paid return envelopes with fecal occult blood testing to improve its effectiveness and save money.

Ambulatory Care↗

Relationship between fecal sampling times and sensitivity and specificity of immunochemical fecal occult blood tests for colorectal cancer: a comparative study.

PURPOSE: The present study was conducted to assess the accuracy of three testing methods using an immunochemical fecal occult blood test based on the number of samples as the optimum means for screening of colorectal cancer. METHOD: One hundred eighty-four patients with colorectal cancer and 368 healthy controls served as the subjects for this study. Each subject was tested by an immunochemical fecal occult blood test for three consecutive days. For evaluation of the most desirable number of sampling times, we used the results of the first day for the one-day method, results of the first and second days for the two-day method, and results of three consecutive days for the three-day method. Sensitivities and specificities of the three testing methods were evaluated. RESULTS: Sensitivities of an immunochemical fecal occult blood test were calculated as 67.9 percent for the one-day method, 88 percent for the two-day method, and 90.8 percent for the three-day method; specificity was as follows: 97.5 percent for the one-day method, 95.6 percent for the two-day method, and 92.1 percent for the three-day method. A significant difference in sensitivity was shown between the one-day and two-day and the one-day and three-day methods (P < 0.01); also, a significant difference in specificity was shown between one-day and three-day and two-day and three-day methods (P <0.05). CONCLUSIONS: These results indicate that the two-day method is recommended for immunochemical fecal occult blood testing as a means of screening for colorectal cancer.

Antibodies, Monoclonal↗

Do aspirin and nonsteroidal anti-inflammatory drugs cause false-positive fecal occult blood test results? A prospective study in a cohort of veterans.

PURPOSE: To determine whether use of regular aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) is a risk factor for a false-positive fecal occult blood test result. METHODS: Consecutive patients referred for colonoscopy for a positive fecal occult blood test result at a Veterans Affairs hospital were eligible. Patients with hematochezia, peptic ulcer disease, or unevaluated dyspepsia requiring antacids, or who used warfarin, were excluded. Regular aspirin and NSAID use was defined as at least one daily dose for at least 3 days per week. Colonoscopic findings unlikely to explain a positive test result alone were defined a priori as diverticulosis, hemorrhoids, or polyps <1.0 cm with no villous histology. Findings likely to explain a positive test result included cancer and advanced polyps. RESULTS: The sample comprised 193 veterans with a mean (+/- SD) age of 66 +/- 10 years; 98% were male and 86% were white. No colonoscopic findings explained the positive fecal occult blood test result in 153 patients (79%). One hundred and thirty-five patients (70%) were regular aspirin or NSAID users, of whom 21% (n = 29) had findings to explain the positive test results, compared with 19% (11/58) of nonusers (P = 0.7). There was no relation between aspirin dose and colonoscopic findings unlikely to explain a positive test result. Multivariate analysis found no association between regular aspirin or NSAID use and a false-positive test result (odds ratio = 0.85; 95% confidence interval: 0.39 to 1.84). CONCLUSION: Aspirin and NSAID use were not risk factors for a false-positive fecal occult blood test result in this study.

Aged↗

Determination of fecal occult blood in primary schoolchildren infected with Trichuris trichiura.

A correlation of Trichuris trichiura infection and fecal occult blood detection was conducted in 146 primary schoolchildren in Narathiwat Province, Thailand. The Kato-Katz thick smear method was used for determining egg counts and stated as eggs per gram of feces (epg). The number of T. trichiura eggs was categorized as class I (1-499 epg), class 11 (500-4,999 epg), and class III (> 5,000 epg), according to the relation between infection intensity and reduced hemoglobin concentration. Each fecal sample was processed to detect occult blood using a guaiac-based test (Hema-Screen, USA) and an immunochromatographic-based test (HEXAGON OBTI test, Germany). There were 50 schoolchildren without parasitic infection in the control group. Of 96 cases with T. trichiura infection, 85 and 11 children were classified in the class I and class II groups, respectively, but no subjects were in the class III group. Positive occult blood detection results in the control, class I, and class II groups using the guaiac and the immunochemical tests were 0, 3.5, and 9.1% (p=0.19), and 0, 2.4, and 36.4%, (p<0.0001) respectively. This study suggests that T. trichiura infection with an intensity of 500 epg or greater may be associated with intestinal bleeding.

Animals↗

Meta-analysis of dietary restriction during fecal occult blood testing.

CONTEXT: Dietary restriction is often recommended during fecal occult blood testing (FOBT) as a means of increasing test accuracy, but concern surrounds whether such restriction also reduces the chance that patients will complete the test. PURPOSE: We conducted a systematic review and meta-analysis to determine if advice about dietary restrictions affects the rate of completion of FOBT and the rate of positive results. METHODS: We searched the MEDLINE database and hand-searched the bibliographies of other systematic reviews and clinical practice guidelines to identify randomized trials of advice to perform dietary restriction during FOBT. We included only trials that reported the proportion of patients who completed the occult blood tests (completion rate). When such information was available, we also recorded the proportion of patients who had positive test results (positivity rate). RESULTS: Five randomized trials met our inclusion criteria. All used guaiac-based Hemoccult tests; none reported results from rehydrated test slides. In four trials, there was little or no difference in test completion between patients assigned to dietary restriction and those with no restriction. In one small trial that used an especially restrictive diet, completion was 21 percentage points lower in the restricted group. Positivity rates were reported in four trials, none of which found a statistically significant difference between groups. Meta-analysis showed no difference in the summary positivity rate between those assigned to dietary restriction versus those not restricted (difference in positivity rate, 0%; 95% CI, -1% to 1%). CONCLUSIONS: Available data suggest that advice to perform modest dietary restriction during unrehydrated FOBT does not affect the completion rate, but more severe restrictions may. Dietary restriction also does not appear to affect positivity rates. On the basis of these data, physicians do not need to advise patients to restrict their diet for nonrehydrated FOBTs.

Aged↗

Fecal occult blood and flexible sigmoidoscopy screening for colorectal cancer: modeling the impact on colonoscopy requirements and cancer detection rates.

AIM: The aim of this study was to estimate the colonoscopy requirements and the likely impact of fecal occult blood and flexible sigmoidoscopy screening on the detection of colorectal cancer by using previously published data. METHODS: Fecal occult blood and flexible sigmoidoscopy screening programs were applied to the 2.04 million subjects aged 50-65 years, at a participation rate of 40%. The following strategies were evaluated: Fecal occult blood testing with colonoscopy follow up of all positive tests; flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps; and flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps > 10 mm in size. RESULTS: The fecal occult blood program detected 5.6% of all colorectal cancer cases at a rate of 2,914 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program detected 14% of all colorectal cancer cases at a rate of 8,160 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program with follow up of adenomatous polyps > 10 mm in size detected 13% of all colorectal cancer cases at a rate of 1,230 colonoscopies/percentage of detection of colorectal cancer. CONCLUSIONS: Flexible sigmoidoscopy screening followed by colonoscopic follow up of adenomatous polyps > 10 mm in size is the most efficient screening strategy in terms of colonoscopies generated and cases of colorectal cancer detected.

Adenomatous Polyps↗

Colorectal cancer screening for the natural population of Beijing with sequential fecal occult blood test: a multicenter study.

OBJECTIVE: To assess the prevalence of colorectal cancer (CRC) in Beijing and the reliability of the sequential fecal occult blood test (SFOBT) for CRC screening. METHODS: Of the natural population (48 100 persons) in several Beijing communities, we screened 26 827 persons with age over 30 using the SFOBT screening program, Guaiacum Fecal Occult Blood Test (GFOBT), Immuno Fecal Occult Blood Test (IFOBT), and colonoscopies. RESULTS: The screening rate of the population was 74%. The positive rate of SFOBT was 5.6%. The prevalence of CRC in the entire population of Beijing was therefore calculated to be 36.57/10(5). Of 12 CRC detected patients, 4 cases were in stage Dukes A (33.33%), 7 cases in stage Dukes B (58.33%), only 1 case (8.34%) in stage Dukes C. CONCLUSIONS: The prevalence of CRC in Beijing is one of the highest in China. Individuals at high risk for CRC or those over 50 years of age should be considered as primary candidates for screening. SFOBT screening is a cost-effective and reliable method for early detection of CRC.

Adult↗

The effect of toilet sanitizers and detergents on immunological occult blood tests.

Effects of time-releasing toilet bowl sanitizers and their main constituents, detergents, on immunological fecal occult blood tests were examined. Six kinds of toilet sanitizers and 19 kinds of detergents were included. Patients' fecal samples and hemoglobin solutions were measured by means of quantitative immunological fecal occult blood tests after being mixed with sanitizer or detergent solutions. Marked reduction in hemoglobin concentration or antigenicity was observed after the addition of sanitizers or detergents at a final concentration of 0.5 g/l. Most of these inhibitory reactions were dose dependent. In contrast with the immunological method, the chemical method using o-tolidine and guaiac were not affected by the detergents tested. In sampling feces for immunological fecal occult blood tests, contact of samples with sanitizer solutions should be avoided.

Detergents↗

False-negative stool occult blood tests caused by ingestion of ascorbic acid (vitamin C).

In a female patient with unexplained anemia, ascorbic acid ingestion and apparent false-negative occult blood tests were related. When she stopped ascorbic acid, her stools became strongly reactive ("4+") by three tests for occult stool blood; this association was observed repeatedly. A test developed to measure stool occult blood in the presence of ascorbic acid remained reactive throughout this observation, and the observation was confirmed by in-vitro studies. Current tests for occult blood depend on the pseudoperoxidase activity of heme and are inhibited by low levels of ascorbic acid. Reducing substances chemically similar to ascorbic acid also inhibits occult blood tests; oxidized ascorbic acid and sulfhydryl reducing agents do not inhibit them at physiologic levels.

Ascorbic Acid↗