Negative Haemoccult^®Test in Malignant and Premalignant Lesions of the Colon

Abstract

To date, no published report on a trial has provided sufficiently strong evidence of the accuracy of the Haemoccult Test assessed by false-negative error, and validated on the basis of a complete colonoscopy of all patients. Total colonoscopy (up to the cecum) was performed on 534 patients whose stools had been tested for occult blood. The results of the colonoscopy were classified as follows: --expected continual bleeding (target lesions: carcinoma, polyps greater than or equal to 10 mm) --intermittant bleeding (polyps less than 10 mm, colitis, etc.), and --no source of bleeding. Results were regarded as false-negative in patients who were found to have a target lesion (carcinoma, polyp greater than or equal to 10 mm) following a negative Haemoccult test. Apart from positive and negative prognostic values, sensitivity and specificity were taken into account as characteristics for the quality of the test. Following a positive Haemoccult test result 46 of the 534 patients were found to have polyps greater than or equal to 10 mm and 22 carcinomas; following negative Haemoccult test results 31 patients were found to have polyps measuring greater than or equal to 10 mm in diameter and 2 carcinomas. On the basis of the chosen classification a false-negative Haemoccult result was established in 8.6% and a false-positive result in 4.3%. The Haemoccult test showed a sensitivity of 67% and a specificity of 93% in patients with target lesions or patients without a source of bleeding.

Value of symptoms and additional diagnostic tests for colorectal cancer in primary care: systematic review and meta-analysis

“…A total of 421 full papers were retrieved, of which 38 were finally considered relevant for the review 1112 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Reference checking yielded 11 additional relevant papers 863 64 65 66 67 68 69 70 71 72 As four papers8 29 30 72 presented information on two studies, our total number of primary diagnostic studies for inclusion was 47.…”

Effect of Verification Bias on the Sensitivity of Fecal Occult Blood Testing: a Meta-Analysis

“…The studies that evaluated the standard guaiac-based FOBT that did not correct for verification bias are listed in Table 1. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] In the last study, the data was presented in two separate publications. These 19 studies included 713 subjects with colorectal cancer and 4181 controls.…”

“…Most studies included subjects who submitted 3 stool specimens [31][32][33][34]36,37,39,41,44,[46][47][48][49][50] while some studies included subjects who only submitted one specimen 35,42,43 or the number was not specified. 38,40,45 Almost all of the studies reported that the specimens were collected at home while one study did not specify the location. 38 The studies listed in Table 1 recruited subjects by two methods: inclusion of patients undergoing colonoscopy for a variety of indications (e.g., FOBT positivity, GI symptoms, colon cancer screening, polyp surveillance) [31][32][33][34][35][36][37][38][39]41,[44][45][46][47] or selection of a group of known colorectal cancer patients and controls undergoing colonoscopy.…”

“…38,40,45 Almost all of the studies reported that the specimens were collected at home while one study did not specify the location. 38 The studies listed in Table 1 recruited subjects by two methods: inclusion of patients undergoing colonoscopy for a variety of indications (e.g., FOBT positivity, GI symptoms, colon cancer screening, polyp surveillance) [31][32][33][34][35][36][37][38][39]41,[44][45][46][47] or selection of a group of known colorectal cancer patients and controls undergoing colonoscopy. 40,42,43,[48][49][50] Both of these methods contain potential verification bias as not all of the FOBT negative patients in the population underwent a confirmatory test.…”

Results of a pilot study of endoscopic screening of first degree relatives of colorectal cancer patients in Italy.

“…Being >60 in age at the start of the programme negatively affected participation (p<0.05). Two cancers were detected and adenomatous polyps were found in another 24 ofthose screened (frequencies: 0.9% and 10.3% respectively). Male gender (p<0.05), increasing age in males (p<0.01), and two or more affected relatives in females (p<0.01) positively affected the frequency of polyps detection.…”