The pros and cons of fecal occult blood testing for colorectal neoplasms

Gynecological cancer and metabolic screening of 1001 elderly Brazilian women

OBJECTIVE

The aim of this study was to evaluate gynecological cancer and metabolic screening of Brazilian women aged 65 years or older.

METHODS

This retrospective descriptive study was conducted by including 1,001 Brazilian patients of the gynecological geriatric outpatient office of our institution to evaluate the influence of age on gynecological cancer and metabolic screening parameters at the first clinical visit. All patients were divided into three groups: a) 65 to 69 years; b) 70 to 74 years; c) ≥ 75 years. We considered clinical, laboratorial, and image data as variables of this study. The Chi-square test was used to assess the proportion of differences among the age groups, and Kruskal-Wallis was used for quantitative variables.

RESULTS

The values of BMI and height in the group over 75 years was lower than that of the 65 to 69 years (p = 0.001). Regardless of the age group, high arterial blood pressure levels were found in 85.45% of participants. Also, many patients had glucose intolerance in the blood. The pelvic ultrasonography showed abnormal endometrial echo thickness (> 5 mm) in 6.14% of patients, but with no significant statistical difference between the age groups. A total of 4.04% of patients had ovaries with high volume values ( > 6.1 mL). Abnormal mammography (BI-RADS 3 or 4) was observed in 12.21%.

CONCLUSIONS

our data suggest that a great reduction in BMI and stature is more frequent in the group over 75 years. Also, systemic arterial hypertension and carbohydrate disturbance are frequent morbidities in women over 65 years.

Screening with faecal occult blood test (FOBT) for colorectal cancer: assessment of two methods that attempt to improve compliance

Screening with the faecal occult blood test (FOBT) has been shown in randomized control trials to be effective in reducing mortality from colorectal cancer. Compliance to this test recommendation, however, by the general population is usually low. To evaluate different methods of increasing compliance with FOBT, using mailed test kits or order cards, with or without information leaflets, subjects were randomly assigned to receive a test kit or a kit request card. An information leaflet was included in half of the mailings. All participants were contacted for interview. Compliance was evaluated through the central computer system of the study's FOBT laboratory. Self-initiated compliance with FOBT in the year preceding the study was 0.6% of the study participants. The overall compliance rate with the programme invitation was 17.9%, with a somewhat higher, though non-significant response to the mailed kit (19.9%) over the kit request card (15.9%). Women complied with the test significantly more than men, older participants more than younger. Compliance to FOBT is low among the Israeli population aged 50-74 who receive a formal invitation to carry out this screening. Mailing a kit request card within the framework of a screening programme can achieve a substantial increase (to 17.9%) in the level of compliance for the relatively low cost of postage. More effort is needed to study additional means of convincing the non-responders to take part in this potentially life saving activity.

Early detection for colorectal cancer: new aspects in fecal occult blood screening

The authors report on promising diagnostic methods of occult intestinal bleeding and discusses the potential new strategy of early detection of colorectal carcinomas in respect to old and new diagnostic measures available. Because of the limited sensitivity and specificity of classical methods used for the demonstration of occult fecal blood, the authors recommend the introduction of new techniques and markers in screening practice. It is presumed that new discoveries in molecular biology will improve the accuracy of early colorectal cancer prevention. Their implementation into routine screening, however, will not take place in the near future. Until their realization, improved screening efficacy is expected from the use of more specific and sensitive blood tests.

Fecal occult blood testing for colorectal cancer. Can we afford not to do this?

Current practice guidelines recommend annual fecal occult blood test screening for colorectal cancer in the average-risk population over the age of 50. Efficacy of fecal occult blood test screening is supported by several controlled prospective trials and case-control studies. Implementation of this recommendation, in combination with periodic flexible sigmoidoscopy every 5 years, is feasible, affordable, highly effective, and has the potential for reducing colorectal cancer mortality by at least 50%. With over 50,000 Americans dying of this malignancy each year, we cannot afford not to do this.

Enteric alpha-1-antitrypsin loss and comparison with Okokit II and Haemoccult for the detection of colorectal cancer

Faecal samples from patients with symptomatic colorectal cancer (n = 19) and from control subjects (n = 54) were analysed for alpha-1-antitrypsin (A1AT) and compared with Haemoccult and Okokit II. A1AT was also measured in paired samples of normal colonic mucosa and cancer tissue (n = 16) and in media from four human colorectal cell lines (COLO 320 DM, SW620, HT29, LS 174T). Faecal A1AT concentrations were greater than controls (P < 0.0001) and detected 12 (63%) patients with cancer compared to 10 (53%) by Okokit II and 7 (37%) by Haemoccult (P > 0.05). A1AT concentrations from colonic mucosa (median, range: 0.46, 0.17-0.79 mg/g wet wt) were greater (P = 0.01) than cancer tissue (0.29, 0.13-0.74 mg/g wt wt). Adjusting for albumin, A1AT concentrations from mucosa (12.0, 3.8-32.2 mg/g albumin) remained greater (P = 0.003) than for cancer tissue (5.9, 2.4-21.4 mg/g albumin). A1AT was not detected in any of the cell-line media. The most likely mechanisms for increased faecal A1AT concentrations, apart from increased blood loss, are increased cell turnover or leakage from epithelial tight junctions. The use of faecal A1AT measurement for the detection of colorectal cancer deserves further assessment.

Detection of colorectal cancer by faecal alpha 1-antitrypsin

Alpha 1-antitrypsin was measured in 5-day faecal collections from patients with colorectal cancer or adenomatous polyps and a symptomatic control group. Collections were homogenized and lyophilized prior to measurement of alpha 1-antitrypsin by radial immuno-diffusion. Colorectal cancer dry weight concentrations were significantly higher than the symptomatic control results, with 57% having results greater than 95% normal values of this control group. There was no significant difference between adenomatous polyp dry weight concentrations and symptomatic control results. Wet weight concentrations were calculated from wet/dry ratios. Colorectal cancer wet weight concentrations were significantly higher than symptomatic control results with 48% having results greater than 95% normal values of this control group. Alpha 1-antitrypsin was also measured in non-lyophilized samples from an asymptomatic control group (n = 39). Colorectal cancer wet weight concentrations were significantly higher than asymptomatic control results, with 62% having results greater than 95% normal values of this control group. Faecal alpha 1-antitrypsin measurement deserves further assessment for use in detecting colorectal cancer.

Effects of high-fiber diet on fecal blood content (HemoQuant assay) in healthy subjects

Consumption of high-fiber diets has been recommended prior to fecal blood testing to increase bleeding from polyps, cancer, and other lesions associated with mucosal erosion in the gastrointestinal tract. The effect of a high-fiber diet on fecal hemoglobin loss was examined in 17 healthy subjects during two dietary periods: (1) self-selected diet, (2) same diet plus 24 g/day dietary fiber (Fiber One Cereal). Five-day fecal composites were weighed and homogenized, and hemoglobin concentration was determined by the HemoQuant test. Average daily fecal weight increased from 145 +/- 90 g to 281 +/- 91 g (P = 0.0001), fecal hemoglobin concentrations decreased from 0.98 +/- 0.48 to 0.48 +/- 0.28 mg/g (P = 0.0001), while daily fecal hemoglobin contents were similar (P = 0.39) for self-selected and added-fiber diets, respectively. In these healthy individuals, a high-fiber diet had no effect on mucosal bleeding, but the increased fecal weight significantly lowered fecal hemoglobin concentration. Clinical implications are considered.

Colorectal cancer: implications of mass screening for public health

The faecal occult blood test (FOBT) for colorectal cancer has a place in clinical practice in case finding, and, perhaps, in screening high-risk groups, but is it a worthwhile screening test when applied to the general population? This question is important and topical: there is increasing interest in Australia in screening by FOBT, but such a programme would be neither free of risk, nor inexpensive. We argue that there is not yet satisfactory evidence that screening by FOBT reduces mortality from colorectal cancer. There is no quicker way of learning whether FOBT saves lives than to wait for the results of the major overseas trials, the first of which should become available in the next three to five years. Until this evidence becomes available, Australia should not proceed with mass screening for colorectal cancer by FOBT. Sporadic and haphazard screening should be discouraged. What we can, and should, do now is find out more about the attitudes and behaviour of consumers and providers of screening by FOBT, the infrastructure that would be required to promote and sustain an effective mass screening programme, the total costs of colorectal cancer screening, and the performance in representative populations of new screening technologies.

Is there a preference for different ways of performing faecal occult blood tests?

Low compliance with faecal occult blood screening reduces the power of clinical trials, potential benefit, and efficiency. It has been proposed that the faecal manipulation required to perform conventional guaiac based tests may be an important factor in low compliance. The aim of this study was to evaluate whether use of a new method (vehicle) of stool collection for the faecal occult blood guaiac test would be preferred to the established standard. A novel self-interpreted test, Early Detector (ED), requires the subject to apply a guaiac/peroxide spray to a stool sample collected simply by wiping the anus with a specimen pad. To determine whether this method would be preferred to the stool manipulation required by Haemoccult (HO) and to compare test validity, employees at a London company were invited to use both tests. Eight-hundred and fifty-seven subjects were shown both tests. Before use, 48% indicated a preference for the method of Early Detector; 24% chose Haemoccult (p less than 0.001), while 28% indicated no immediate preference. Seven-hundred and one performed both tests. After use, 74% preferred ED; 5% preferred HO (p less than 0.001); 21% had no preference (NP). The preference for the ED test method was consistent by sex categories, age groups and occupational class. Logistics, aesthetics, and immediacy of results were the main reasons indicated for choosing ED. Whether the preference for ED could result in higher compliance remains to be proven. Its high positivity (14%), however, would preclude its use as a sole test to determine the need for endoscopic and/or radiologic investigation in the screened patient.

Repeated screening for colorectal cancer with fecal occult blood test. A prospective randomized study at Funen, Denmark

Two screenings with Hemoccult-II were performed in a randomized study, allocating 30,970 persons to screening and 30,968 as controls in a population of 140,000 between 45 and 74 years old on the island of Funen, Denmark. The test was completed in 20,672 initially and in 18,779 of these during rescreening 2 years later. Positive H-II tests were found in 215 and 159 persons during the two screenings, respectively. A total colonoscopy was performed in 187 and 144, and cancer was detected in 37 and 13 and adenomata in 86 and 76, respectively. Interval cancers had developed in 40 persons at the end of the second screening, and 39 non-responders had developed cancer. Cancer was diagnosed in 115 controls and an adenoma in 100 during the same period. Interval cancers presented as rectal cancers more frequently than those detected by screening. Early cancers were more frequent in the screening group, and, accordingly, more patients had curative and also less extensive surgery, with a low postoperative mortality. The total number of deaths from colorectal cancer was 37 in the screening group, including interval cancers and cancers in non-responders and persons who developed cancer before they could be invited, which suggests a reduction in mortality of 27% (51 deaths among controls, compared with 37). The reduction is as yet not statistically significant, and final evaluation must await at least one more screening, ending in 1990, and a follow-up of some years. Removal of more large adenomas during screening makes it possible that the incidence of cancer will decrease.