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Survey of the opinions, knowledge, and practices of gastroenterologists regarding colorectal cancer screening and use of the fecal occult blood test.

OBJECTIVES: Primary care physicians and internal medicine residents have poor understanding of colorectal cancer screening and the use of fecal occult blood tests. If acceptance and implementation of colorectal cancer screening is to improve, gastroenterologists may have to take a more leading role in the education of their primary care colleagues, physicians in training, and the general public. However, before this can be recommended, it is necessary to determine how closely gastroenterologists follow currently recommended guidelines and how they use fecal occult blood tests. METHODS: We mailed a two-page, structured questionnaire about colorectal cancer screening and use of fecal occult blood tests to 8000 randomly selected gastroenterologists in the United States. RESULTS: We received responses from 24% of the gastroenterologists. Almost all used fecal occult blood tests in the office setting, 86% on stool obtained at rectal examination. The test was frequently used for reasons other than colorectal cancer screening, and often without adequate patient instruction on dietary and medication restrictions. Of the respondents, 98% commenced screening at age < or = 50 yr, whereas 37% either continued screening into advanced age or never stopped. Annual fecal occult blood testing with flexible sigmoidoscopy every 5 yr was the screening strategy recommended by 71% of the respondents, whereas 25% recommended colonoscopy every 10 yr. However, 77% of the gastroenterologists chose colonoscopy for personal colorectal cancer screening. CONCLUSIONS: Gastroenterologists usually give appropriate advice on colorectal cancer screening but often misuse fecal occult blood tests. This may produce excessively high false-positive screening rates, leading to unnecessary diagnostic testing without apparent benefit.

Attitude of Health Personnel↗

Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study.

BACKGROUND: Although tests for occult blood in the feces are widely used to screen for colorectal cancers, there is no conclusive evidence that they reduce mortality from this cause. We evaluated a fecal occult-blood test in a randomized trial and documented its effectiveness. METHODS: We randomly assigned 46,551 participants 50 to 80 years of age to screening for colorectal cancer once a year, to screening every two years, or to a control group. Participants who were screened submitted six guaiac-impregnated paper slides with two smears from each of three consecutive stools. About 83 percent of the slides were rehydrated. Participants who tested positive underwent a diagnostic evaluation that included colonoscopy. Vital status was ascertained for all study participants during 13 years of follow-up. A committee determined causes of death. A single pathologist determined the stage of each tissue specimen. Differences in mortality from colorectal cancer, the primary study end point, were monitored with the sequential log-rank statistic. RESULTS: The 13-year cumulative mortality per 1000 from colorectal cancer was 5.88 in the annually screened group (95 percent confidence interval, 4.61 to 7.15), 8.33 in the biennially screened group (95 percent confidence interval, 6.82 to 9.84), and 8.83 in the control group (95 percent confidence interval, 7.26 to 10.40). The rate in the annually screened group, but not in the biennially screened group, was significantly lower than that in the control group. Reduced mortality in the annually screened group was accompanied by improved survival in those with colorectal cancer and a shift to detection at an earlier stage of cancer. CONCLUSIONS: Annual fecal occult-blood testing with rehydration of the samples decreased the 13-year cumulative mortality from colorectal cancer by 33 percent.

Aged↗

Evaluation of a desk top instrument for the automated development and immunochemical quantification of fecal occult blood.

BACKGROUND: The guaiac fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is user dependent and not specific for human hemoglobin (Hb). The automated-developed, quantitative, immunochemical human Hb FOBT (I-FOBT) is specific, allows for quality control and selection of a suitable Hb level, with optimal sensitivity and specificity, for colonoscopy. MATERIAL/METHODS: We evaluated a desktop instrument, OC-MICRO (Eiken, Japan), which automatically develops and quantifies 50 fecal tests/hr for Hb; for ease of use, test reproducibility and stability and intra-patient daily I-FOBT variation; clinical evaluation included sensitivity and specificity for neoplasia in patients undergoing colonoscopy. RESULTS: Five hundred patients prepared 3 fecal tests which were quantified for Hb, I-FOBT samples were: (1) repeatedly re-examined; (2) stored at 4 degrees C or 20 degrees C or 28 degrees C and re-examined; (3) I-FOBT levels correlated with colonoscopic findings. Five I-FOBTs re-examined 6 times had no significant changes; 30 tests stored > or = 21 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). Receiver operator characteristic curve analysis showed that at the 100 ng Hb/mL I-FOBT level 76.5% of CRCs and advanced adenomas were detected with a specificity of 95.3%. CONCLUSIONS: The instrument provided reproducible results and refrigerated I-FOBT samples were stable 21 days. An I-FOBT level can be chosen to provide optimal sensitivity and specificity for significant neoplasia.

Colonoscopy↗

Mailings timed to patients' appointments: a controlled trial of fecal occult blood test cards.

BACKGROUND: Fecal occult blood testing (FOBT) programs cost-effectively reduce colon cancer mortality. To improve the rate of colon cancer screening with FOBT, we tested the effect of mailing FOBT cards timed to appointments on the rates of completion of FOBT. DESIGN: Controlled trial. SETTING/PARTICIPANTS: A total of 119 patients with primary care appointments scheduled in May or June 2000 for an urban, public hospital clinic that serves predominantly low-income, African Americans with chronic diseases. The patients in the study were selected by linking a quality improvement registry, the appointment system database, and an FOBT database to generate a list of clinic patients who had not completed an FOBT in the preceding year. INTERVENTION: Subjects were assigned to either a system of mailing FOBT cards and reminders 2 weeks prior to a scheduled appointment or usual care. MAIN OUTCOME MEASURES: The primary outcomes were the rate of screening at the index appointment and during the year beginning with the date of the index appointment. RESULTS: The rate of return of the FOBT cards during the year beginning with the index appointment was 40.7% for the intervention group compared to 5% for the usual care group (odds ratio [OR]=13.0, p <0.001). The difference was accounted for largely by increases in screening at the index appointment (35.6% compared to 3.3%, OR=16.0, p <0.001). CONCLUSIONS: Using computer databases to generate a list of patients due for FOBT and then mailing FOBT cards timed to a scheduled appointment significantly increased the rate of colon cancer screening. This may be an efficient approach to increasing colon cancer screening with FOBT.

Appointments and Schedules↗

Basic variables at different positivity thresholds of a quantitative immunochemical test for faecal occult blood.

OBJECTIVES: Screening by faecal occult blood testing (FOBT) is effective in decreasing mortality and incidence of colorectal cancer (CRC). Immunochemical tests have proved to be more cost effective than guaiac FOBTs. The latex agglutination test (LAT) has the advantage of being a fully automated, quantitative test. The aim of this study is to interpret the overall experience with LAT according to different positivity thresholds. SETTING: A population based screening programme is currently running involving subjects aged 50-70, invited every 2 years to have an FOBT. LAT is the standard screening test and has a positivity threshold for further diagnostic tests of 100 ng haemoglobin/ml of sample solution. METHODS: Positivity rates, detection rates for CRC high risk adenomas, and positive predictive values for CRC, high risk adenomas, and low risk adenomas were calculated for several positivity thresholds. RESULTS: 19,132 attendances at screening were recorded (11,774 at first screening, 7358 at subsequent screenings). Progressively increasing the positivity threshold from 100 to 200 ng/ml showed (a) a decrease in positivity rate; (b) a decrease in detection rates for CRC or high risk adenomas; (c) an increase in positive predictive values for cancer; (d) an increase in positive predictive value for high risk adenomas. CONCLUSIONS: Increasing the positivity threshold of the LAT reduces recall rate and improves positive predictive value for cancer or high risk adenomas but substantially decreases the detection rate of CRC and high risk adenomas. For this reason increasing the positivity cut off for LATs is not advisable. On the other hand decreasing the positivity threshold would increase recall rate and sensitivity of screening. Careful evaluation of sensitivity of the quantitative results of the LAT for interval cancers is needed to definitively assess the optimal positivity threshold for LATs in population based screening programmes.

Adenoma↗

Relative frequency of upper gastrointestinal and colonic lesions in patients with positive fecal occult-blood tests.

BACKGROUND: Although bleeding lesions anywhere in the gastrointestinal tract can cause a positive reaction on guaiac-based fecal occult-blood tests, the relative frequency of upper gastrointestinal and colonic lesions is unknown. METHODS: During a period of 30 months, we prospectively studied all patients with at least one stool specimen containing fecal occult blood who were referred for further evaluation. Fecal occult blood was detected by standard guaiac-based tests of stool specimens obtained as part of routine screening or of stool obtained by digital rectal examination. Patients with documented iron-deficiency anemia or active gastrointestinal bleeding were excluded from the study. All participants had a detailed history taken and underwent colonoscopy, followed by esophagogastroduodenoscopy. RESULTS: Of the 409 patients with fecal occult blood who were referred, 310 were potentially eligible to participate, and 248 (mean age, 61 years; range, 40 to 89) were studied; 40 percent were women. We identified lesions consistent with occult bleeding in 119 patients (48 percent); in 71 bleeding lesions were found in the upper gastrointestinal tract, and in 54 they were identified in the colon. Six patients had abnormalities in both areas. The most common upper gastrointestinal lesions were esophagitis (23 patients), gastric ulcer (14), gastritis (12), and duodenal ulcer (10). Thirty patients with lesions in the upper gastrointestinal tract were long-term users of aspirin, ethanol, nonsteroidal antiinflammatory drugs, or a combination of these substances. The most common colonic lesions were adenomas more than 1.0 cm in diameter (29 patients), carcinoma (13), colitis (5), and vascular ectasia (5). Although the overall sensitivity of symptoms for the detection of gastrointestinal lesions was low, logistic-regression analysis demonstrated that the presence of symptoms in the upper gastrointestinal tract was associated with the detection of lesions in the upper gastrointestinal tract (odds ratio, 2.6; 95 percent confidence interval, 1.4 to 4.7). In both patients with symptoms and those without symptoms, the prevalence of lesions in the upper gastrointestinal tract was greater than or equal to that of colonic lesions. CONCLUSIONS: In a group of patients with positive fecal occult-blood tests who were referred for further evaluation, from which those with iron-deficiency anemia and active bleeding had been excluded, upper gastrointestinal lesions were identified more frequently than colonic lesions.

Aged↗

Fecal occult blood testing for colorectal cancer in an ethnically diverse population.

Fecal occult blood test kits were distributed throughout the ethnically diverse Hawaiian Islands during a 3-week period in 1989. Occult blood was detected in 1,631 persons (11.8%). At least 83% of the participants with positive tests sought medical advice. Subsequently, 76 (4.7%) were diagnosed as having colorectal adenomas and an additional 1.4% had malignant neoplasms (3 gastric and 20 colorectal adenocarcinomas). Three quarters of the colorectal cancers were localized and node-negative. Participation in this program and the type of diagnostic studies done on participants with positive tests varied according to sex and ethnicity. Therefore, these demographic variables must be considered in designing fecal occult blood screening programs.

Adolescent↗

Effect of diet on results obtained by use of two commercial test kits for detection of occult blood in feces of dogs.

To evaluate the effect of diet on results obtained by use of 2 commercial test kits for detection of occult blood in feces, 5 dogs were fed 7 diets in randomized sequence. Dry and canned diets with various principal ingredients were evaluated. Each diet was offered twice over a 24-hour period, followed by a 36-hour nonfeeding period. Fecal specimens were collected twice daily, and tests for occult blood were performed within 12 hours. The dietary origin of fecal specimens was confirmed by use of colored markers fed with each diet, and was correlated with estimates of gastrointestinal tract transit time. A modified guaiac paper test and an o-tolidine tablet test were performed on each specimen. Of 59 specimens, 4 were positive for occult blood, using the o-tolidine tablet test. Three positive results were associated with a mutton-based canned diet, and 1 positive result was associated with a canned beef-based diet. Of 59 specimens, 11 were positive for occult blood, using the modified guaiac paper test. Four positive results were associated with the mutton diet, and 3 positive results were associated with the beef diet. Of the remaining 5 diets, 4 caused 1 positive reaction. Results were inconsistent with the null hypothesis that the distribution of positive occult blood test results is not affected by diet (P < 0.025), and indicate that diet can affect the specificity of peroxidase-based tests for detection of occult blood in canine feces. Diet modification prior to testing is recommended.

Animal Feed↗

Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy.

BACKGROUND: The high incidence of and mortality from colorectal cancer (160,000 new cases and 60,000 deaths in the United States each year) are compelling public health concerns. Following the evolution of effective surgery for this disease since the 1960s, the focus has been on improving methods of detection and integrating them into effective screening programs. PURPOSE: This was the first study to evaluate the effectiveness, in a setting of comprehensive medical examinations, of using the fecal occult blood test in conjunction with sigmoidoscopy, rather than sigmoidoscopy alone, to screen for colorectal cancer. Our end points were extent of compliance with fecal occult blood test and sigmoidoscopy, numbers of cancers detected, and mortality rate. METHODS: From 1975 through 1979, a total of 21,756 patients (aged 40 and older) who presented at the Preventive Medicine Institute-Strang Clinic for routine medical examinations were enrolled by calendar period into study and control groups. Study patients were offered annually both rigid sigmoidoscopy examinations and fecal occult blood tests requiring two stool specimens per day for 3 days, while control patients were offered only annual sigmoidoscopy. The majority of fecal occult blood test cards were not rehydrated before assay. Patients with positive tests were referred for double-contrast barium enema and colonoscopy. Two distinct trials were carried out. Trial I was primarily a demonstration of feasibility of using the fecal occult blood test as a supplemental screening method. Of the 9277 participants, 7168 (77%) were assigned to the study group and offered the fecal occult blood test. In trial II, approximately half of the 12,479 patients were assigned to each group. Patients in both trials had follow-up through 1984. RESULTS: Compliance with the fecal occult blood test was initially high in both trials, but diminished such that only 56% of study patients in trial I and 20% of those in trial II returned for second tests. On the initial (prevalence) screen, a substantial number of early-stage cancers were detected by the fecal occult blood test, primarily in trial II. In trial II, survival probability was significantly greater (P < .001) in the study group than in the controls (70% versus 48%), and colorectal cancer mortality was lower (0.36 versus 0.63) with borderline significance (P = .053, one-sided). CONCLUSIONS AND IMPLICATIONS: The screening of average-risk individuals (aged 50 and older) for colorectal cancer through use of the fecal occult blood test in conjunction with sigmoidoscopy can increase the likelihood of early detection of this disease. This practice, coupled with prompt diagnostic work-up following positive tests, will result in treatment of earlier stage cancers and increased survival after treatment.

Aged↗

Evaluation of an immunochemical test for faecal occult blood in screening for colorectal neoplasia in a high risk group.

A group of 1615 asymptomatic individuals presumed to be at increased risk of colorectal neoplasia were selected as the study group. All were tested by an immunochemical test for faecal occult blood. In the second half of the study, individuals who were occult blood negative were offered colonoscopy. Ninety-nine individuals (6.1%) returned stools which were occult blood positive. Investigation by full colonoscopy was possible in 90 cases, revealing nine patients (10%) with invasive cancers, four patients (4.4%) with carcinomata in situ, and 36 patients (40%) with adenomata. Non-neoplastic pathology capable of producing occult blood positive stools was found in 31 individuals (34.4%). No pathology was found in 10 instances (11.1%). Of the 53 occult blood negative subjects who underwent colonoscopy, eight were found to have adenomata. Only one of these was larger than 5 mm in diameter (18 mm). No carcinomata were found. The site within the large bowel of the tumour did not appear to significantly affect the occult blood status of the faeces but the size of the tumours detected suggests that the presence of blood within the stool is more likely to be associated with larger lesions. The frequency of detection of both carcinomata and adenomata was greatest in individuals who had a past history of colorectal neoplasia. The individual cost of this immunochemical test is nominal. The high diagnostic yield and low false positive and negative rates suggest that case follow-up, surveillance, or screening utilizing this test is justified.

Adult↗

[Colorectal cancer in general practice--what is the benefit of testing for occult blood in feces?].

BACKGROUND: We wanted to examine the extent and value of testing in a general practice for occult blood in faeces in patients suspected of having colorectal cancer. MATERIAL: All patients treated for colorectal cancer in the surgical department in the district hospital 1985-98 were registered (n = 880) and names compared to the files in a general practice in Arendal. The files of our patients were examined in order to determine patients' and doctor's delay in diagnosing the disease and whether testing of occult blood in faeces was used in the examination. In addition, all patients in the practice tested with occult blood in faeces (Hemofec) 1985-94 were noted (n = 962) and the files of 20 % of them examined. RESULTS: The five general practitioners in our practice were responsible for diagnosing 74 of the patients with verified colorectal cancer (approx. one new patient per doctor per year). Patients' mean delay was 1.7 months (median 1.1), doctor's delay mean 1.8 months (median 0.9). In 25 patients the examination of occult blood in faeces was part of the diagnostic workup. 20 of the patients tested positively, five negatively. In 71%, the reason for testing was non-specific abdominal symptoms. Among these patients, 11% tested positively and 89% negatively. INTERPRETATION: Examination of occult blood in faeces has a limited role to play in the diagnosing of colorectal cancer, though a negative result is valuable in order to exclude colorectal cancer in patients with non-specific abdominal complaints and thus prevent unnecessary use of colonoscopy.

Adult↗

Predictors of older adults' participation in fecal occult blood screening.

This study describes variables that predicted participation in fecal occult blood screening. Orem's theory provides the conceptual basis for this descriptive research study. As part of the research, the American Cancer Society's (ACS) colorectal cancer educational program was given to 171 participants of a congregate meal program. Forty-seven percent of the respondents submitted specimens for occult blood testing. Female gender was the only demographic variable found to predict participation in the fecal occult blood screening. The ability to use the telephone, shop for groceries or clothes, and clean house were associated with submission of a fecal specimen. Respondents who assessed their eyesight and hearing as good did not differ from other respondents in regard to submitting fecal specimens. Implications for health education, early detection, and oncology and gerontological nursing are identified.

Activities of Daily Living↗

Value of faecal alpha-1-antitrypsin, haemoglobin and a chemical occult blood test in the detection of gastrointestinal disease.

Specimens from hospital out-patients and in-patients sent for faecal occult blood tests were also analysed for faecal alpha-1-antitrypsin and faecal haemoglobin. 453 stool specimens from 222 patients were analysed. The clinicians were only aware of the faecal occult blood test results, and diagnoses were made using conventional clinical and investigative criteria. Gastrointestinal bleeding or putative sites of bleeding were diagnosed in 98 patients, whereas in 81 patients putative sites of bleeding were not found or other cause of anaemia diagnosed. In 41 patients there was insufficient information to reach a definitive diagnosis. Comparison of the 3 faecal tests using these grouping methods showed that faecal alpha-1-antitrypsin performed best, with an accuracy of 89%, specificity of 90% and sensitivity of 88%, all significantly better (P < 0.001) than the faecal occult blood test (68%, 60% and 73%, respectively). There was no significant difference between the performance of the faecal occult blood and faecal haemoglobin tests. Faecal alpha-1-antitrypsin measurement may be a useful investigation in situations where a faecal occult blood test would normally be requested.

Adolescent↗

A randomized controlled trial of a clinic-based support staff intervention to increase the rate of fecal occult blood test ordering.

BACKGROUND: Colorectal cancer is the second most common fatal malignancy in the United States. Early detection using fecal occult blood tests has been shown to reduce mortality, but these tests are underutilized among those eligible for this screening. Attempts to increase use of fecal occult blood tests in eligible populations have focused on the provider, patient, or system. But none have examined whether a support-staff intervention is effective in achieving this aim. We therefore conducted a randomized controlled trial to test the impact of authorizing support staff to order fecal occult blood tests in a general internal medicine clinic organized into four teams. METHODS: A total of 1,109 patients were included in the study, 545 of whom were in the two teams randomized to treatment. Univariate and multivariate regression analyses were used to evaluate the impact of the intervention. RESULTS: The intervention resulted in significantly more fecal occult blood test ordering in the treatment group than in the control group for all patients (52% vs 15%, P < 0.001). Treatment fecal occult blood test cards were returned as frequently as the control cards for all patients (44% vs 48%, P = 0.571). CONCLUSION: Delegation of selected screening tasks to support staff can enhance patient access to preventive care.

Colorectal Neoplasms↗

Occult-blood screening for colorectal carcinoma: the risks.

The evidence that occult-blood (Hemoccult) screening for colorectal carcinoma is beneficial has been examined in a companion paper. No data have yet been published demonstrating actual reductions in morbidity or mortality among patients undergoing the test. In this paper the risks of occult-blood screening are examined. It is shown that significant harm may result from the test's widespread application, due to the need for extensive endoscopic and radiological investigations in persons with a positive result (the vast majority of whom will subsequently be found not to have cancer). Furthermore, the most favorable benefit-risk ratio in Hemoccult screening (i.e., the highest positive predictive value for cancer) is found among persons over 70 years of age. Yet they are generally the least likely of patients screened to undergo treatment if a cancer is found. It is concluded that the risks of occult-blood screening could outweigh the benefits of any age group.

Adult↗

The relative value of fecal occult blood tests and flexible sigmoidoscopy in screening for large bowel neoplasia.

The secondary prevention of colorectal cancer is based on the early detection of noninvasive cancer and removal of adenomatous polyps. The two commonly used screening tests are flexible sigmoidoscopy and guaiac fecal occult blood testing. Both were performed simultaneously and independently on 1176 asymptomatic volunteers followed by colonoscopic examination if either occult blood or a neoplasm was detected. Neoplasia (adenomatous polyps or cancer) were found in 48 screenees. Only ten had positive stool occult blood while 45 were detected by sigmoidoscopy. Analysis of sensitivity for neoplasia was 93.8% for sigmoidoscopy but only 20.8% for the occult blood tests, while the positive predictive values for neoplasia were 100% and 23.8% respectively. The fecal occult blood test detected only 18% of screenees with adenomas and 60% with invasive cancer. Flexible sigmoidoscopy detected 95% and 80% respectively. Analysis (kappa statistic) demonstrated little agreement between the two tests (P greater than 0.05), indicating that they are diagnosing different neoplasia. Evaluation of expected gain in diagnosing neoplasia, by combining both tests, gave 18% for the fecal blood test and 94% for the endoscopic test. These results confirm the complementary value of performing both tests, but especially the high sensitivity and predictive value positive of flexible sigmoidoscopy for adenomas, including those with severe dysplasia, and the converse for the fecal occult blood test. This latter test must be recommended and used within a screening program with caution and full understanding of its limitations.

Adult↗

[Significance of the stool occult blood test in patients with thrombotic disease under treatment with low dose aspirin].

We encountered lower gastrointestinal bleeding in 16 patients taking a low dose of aspirin and examined the effect of low aspirin dose on the stool occult blood test in 49 thrombotic patients (mean: 76.7 +/- 9.6 years old) including 39 with cerebral infarction, 8 with ischemic heart disease and 2 with atrial fibrillation. The mean aspirin dosage was 81 mg/day over a period of 6-288 weeks (mean: 86.4 +/- 66.9 weeks). Positive occult blood test was seen in 16/49 (32.7%). Severe lower gastrointestinal bleeding was observed in one case (2%) with colon diverticulosis. Aspirin dosage per patient was significantly higher (p<0.01) in the occult blood test positive group (60.1 +/- 47.2 g) than in the occult blood test negative group (42.6 +/- 32.8 g). The positive ratio of occult blood test was significantly higher (p<0.01) in the aspirin and antithrombotic drugs-taking group (8/5; positive/negative) than in the aspirin-taking group (8/28; p/n), whereas it was not significant between the aspirin taking-group and aspirin not taking-group. The odds ratio between aspirin and antithrombotic drugs (warfarin, beraprost, cilostazol or ticlopidine)-taking group and the aspirin-taking group was 3.47 (p<0.05). A low dose of aspirin was associated with a positive occult blood test. Aspirin should be carefully administered when patient has a diverticle or is taking other antithrombotic drugs.

Aged↗