Occult Blood Screening Research Articles

PTU-039 Colonoscopic Polyp Detection Rate is Stable Throughout the Workday including in evening Colonoscopy Sessions

IntroductionPolyp detection rate (PDR) is an accepted measure of quality of colonoscopy. Several factors may influence PDR including time of procedure and rank of colonoscopy within a session. Our unit...

Colonoscopic surveillance of first-degree relatives of colorectal cancer patients in a faecal occult blood screening programme

Background: In some Italian areas, colonoscopic surveillance of first-degree relatives (FDRs) of colorectal cancer (CRC) patients is provided as a part of local population-based faecal occult blood test (FOBT) screening programmes. The objective of the present study was to assess the feasibility and early results of this surveillance model. Methods: Data from district screening centres were used to evaluate the process of identification and selection of eligible FDRs (residence in the Emilia-Romagna Region, age 40–75 years, no recent colonoscopy) of screen-detected CRC patients and the detected prevalence of disease. The probability for an FDR to undergo colonoscopy and to be diagnosed with CRC and advanced adenoma was estimated using the Kaplan–Meier method. The sex- and age-standardised ratio of detected prevalence to that expected based on results from a colonoscopy screening study of the Italian general population was estimated. Results: Between 2005 and 2011, 9319 FDRs of 2437 screen-detected CRC patients (3.8 per patient) were identified and contacted. Their likelihood of being eligible for, and accepting, colonoscopy was 0.11 (95% confidence interval: 0.11–0.12). Among the 926 subjects undergoing colonoscopy, the prevalence of previous negative screening FOBT was 63%. Eleven CRCs (1.2%) and 100 advanced adenomas (10.8%) were detected. The standardised ratio of detected prevalence to that expected was 0.91 (95% confidence interval: 0.19–2.66) for CRC and 1.48 (1.04–2.05) for advanced adenoma. Conclusions: The procedure of selection of FDRs was extremely ineffective. Due to previous negative screening tests, the prevalence of disease was less than expected. A population-based FOBT screening programme is a highly unsuitable setting for the provision of surveillance to FDRs of CRC patients.

Detection of cadherin-17 in human colon cancer LIM1215 cell secretome and tumour xenograft-derived interstitial fluid and plasma

Colorectal cancer (CRC), one of the most prevalent cancers in the western world, is treatable if detected early. However, 70% of CRC is detected at an advanced stage. This is largely due to the inadequacy of current faecal occult blood screening testing and costs involved in conducting population-based colonoscopy, the ‘gold standard’ for CRC detection. Another biomarker for CRC, carcinoembryonic antigen, while useful for monitoring CRC recurrence, is ineffective, lacking the specificity required early detection of CRC. For these reasons there is a need for more effective blood-based markers for early CRC detection. In this study we targeted glycoproteins secreted from the human colon carcinoma cell line LIM1215 as a source of potential CRC biomarkers. Secreted candidate glycoproteins were confirmed by MS and validated by Western blot analysis of tissue/tumour interstitial fluid (Tif) from LIM1215 xenograft tumours grown in immunocompromised mice. Overall, 39 glycoproteins were identified in LIM1215 culture media (CCM) and 5 glycoproteins in LIM1215 tumour xenograft Tif; of these, cadherin-17 (CDH17), galectin-3 binding protein (LGALS3BP), and tyrosine-protein kinase-like 7 (PTK7) were identified in both CM and glycosylation motifs. Swiss-Prot was used to annotate Tif. Many of the glycoproteins identified in this study (e.g., AREG, DSG2, EFNA1, EFNA3, EFNA4, EPHB4, ST14, and TIMP1) have been reported to be implicated in CRC biology. Interestingly, the cadherin-17 ectodomain, but not full length cadherin-17, was identified in CM, Tif and plasma derived from mice bearing the LIM1215 xenograft tumour. To our knowledge, this is the first report of the cadherin-17 ectodomain in plasma. In this study, we report for the first time that the presence of full-length cadherin-17 in exosomes released into the CM. This article is part of a Special Issue entitled: An Updated Secretome.

Knowledge of Colorectal Cancer Screening among Young Malaysians

The objective of this study was to determine the knowledge and associated factors regarding colorectal cancer screening among university students in Malaysia. The questionnaire consisted of three parts: socio-demographic characteristics, lifestyle practice and knowledge of colorectal screening. A cross-sectional study was conducted among 300 students (21.3±1.4 years old). The majority of the participants were Malay with a monthly family income of less than 5,000 Ringgit Malaysia (equal to 1,700 USD) (67.0% and 76.0%, respectively). Regarding their lifestyle practices, the majority were non-smokers and had never consumed alcohol (83.7%, and 88.0%, respectively). The majority of the participants had no knowledge of digital rectal examination, colonoscopy, barium enema and fecal occult blood screening (63.3%, 60.7%, 74.0% and 62.3%, respectively). Univariate and multivariate analysis revealed that their age and the discipline which the students were studying significantly influenced their level of knowledge about colorectal screening. The present study results indicate that education campaigns about colorectal cancer should be promoted.

PS2-22: Exploring the Course of Psychological Distress and Perceived Health Status After Receiving a Positive Fecal Occult Blood Test Result

Background/Aims Colorectal cancer (CRC) screening reduces morbidity and mortality. It is important to understand the effect of a positive fecal occult blood (FOB) screening test result on mental health and general well-being. The goal of this study is to evaluate differences in colon cancer worry, general anxiety and perceived health status among individuals receiving FOBT(+) and FOBT (−) results at 7–14 days and 4 months post screening. The study is the first to simultaneously chart mental and physical well-being associated with CRC screening.

Slipping through the bowel cancer screening programme

Colorectal cancer is common and a leading cause of cancer death. Faecal occult blood screening has been shown to reduce mortality. The aim of this study was to identify patients in Gloucestershire with a new diagnosis of colorectal cancer who had previously been screened via the Bowel Cancer Screening Programme (BCSP). Between 2006 and 2009, 1030 patients were diagnosed with colorectal cancer. Of these 237 (23%) had been invited to be screened via the BCSP. Their clinical notes were analysed. Fifty-seven (24%) of the 237 patients had previously had a negative faecal occult blood result. Thirty-three (14%) had their cancer discovered as part of the BCSP. Seventy (30%) had already been diagnosed with colorectal cancer prior to invitation, 62 (26%) did not respond to the invitation, nine (4%) were registered outside Gloucestershire and had therefore not been invited, and three (3%) had died before the invitation. Of the 57 patients with a negative faecal occult blood test, 47 (83%) had colorectal cancer staged Dukes B or C, and 34 (60%) had a rectal or sigmoid cancer. Patients will present with colorectal cancer despite having been invited to participate in the BCSP, with many having received a negative faecal occult blood test. This could be considered a high false negative rate.

PWE-076 Continued biennial screening of faecal occult blood test (FOBT) positive and screening colonoscopy negative cohort in English bowel cancer screening programme—is it necessary?

IntroductionThe English NHS Bowel Cancer Screening Programme (BCSP) uses guaiac based faecal occult blood test (FOBT) as the screening tool, with people with a positive result undergoing colonoscopy. Subjects with...

Preventing bowel cancer: an insight for clinicians

Worldwide, colorectal cancer causes 610,000 deaths annually with 38,000 new cases diagnosed in the UK and 16,000 deaths each year. The prognosis is directly related to the staging of the cancer at diagnosis, with an overall 5-year survival rate of approximately 50%. However, for localized disease the figure is much higher at 90%, although unfortunately many cancers present at an advanced stage. Importantly, there is the potential to reduce the incidence because most tumours arise from premalignant adenomatous polyps, which if detected and removed interrupts the adenoma-adenocarcinoma sequence. In addition, identifying colorectal cancer at an early stage can impact on the mortality rates for this neoplasm. The current screening options for bowel cancer include analysis of stool for occult blood and endoscopic assessments of the colorectum, including flexible sigmoidoscopy and full colonoscopy. The aim of this review is to present information on the natural history of colorectal cancer, the evaluation of the different screening modalities and the current faecal occult blood screening program within the UK National Health Service, and to discuss how dietary factors and aspirin may affect aetiology.

Cost-Effectiveness of Mass Screening for Colorectal Cancer: Choice of Fecal Occult Blood Test and Screening Strategy

Colorectal cancer is a major cause of mortality. This gives high public health priority to mass screening using a noninvasive, fecal occult blood test of asymptomatic individuals. A positive test selects those who should undergo colonoscopy to ensure early detection of colorectal cancer. Guaiac fecal occult blood test has low sensitivity. Automated immunochemical tests that measure the fecal human hemoglobin concentration are more sensitive and can be simplified as a 1- to 3-sample format with optimum cutoff points. The aim was to improve the sensitivity of the test by choosing an accurate format (1- to 3-sample and optimum hemoglobin concentration) while maintaining acceptable specificity and avoiding alteration of the screening program in terms of quality of life and economic outputs. We used a Markov model to estimate the cost-effectiveness of a screening program for a population of 100,000 asymptomatic individuals by use of immunological fecal tests with different cutoffs, leading to different sensitivity/specificity ratios, and to compare its incremental cost-effectiveness ratio compared with the guaiac fecal test program. The results suggest that a 3-sample immunological test with 50 ng/mL as a positive cutoff is cost-effective. It provides more asymptomatic cancer detection without significantly increasing normal colonoscopies. This format should be prospectively evaluated in mass screening.

Patients’ experiences and reported barriers to colonoscopy in the screening context—A systematic review of the literature

ObjectiveA systematic review of the literature was conducted to characterise patients’ own experience of colonoscopy in the screening context. MethodsA search strategy was applied in MEDLINE, EMBASE and PSYCHinfo (1996–2009). Thematic analysis and narrative summary techniques were used. ResultsFifty-six studies met eligibility criteria and were included in the analysis. Seven studies examined patients’ views after having colonoscopy. Forty-seven studies addressed patient-reported barriers to an anticipated primary colonoscopy. Most patients perceived the laxative bowel preparation to be the most burdensome part of colonoscopy. Other reported difficulties included anxiety, anticipation of pain, feelings of embarrassment and vulnerability. Inadequate knowledge and fear of finding cancer were identified as obstacles to the uptake of screening colonoscopy. Physician endorsement, having a family history, knowing someone with cancer, and perceived accuracy of the test were incentives to having a colonoscopy. Two studies focused on colonoscopy after faecal occult blood screening. Similar procedural, personal, and practical concerns were reported. ConclusionsBowel preparation, lack of awareness of the importance of screening, and feelings of vulnerability in women are all significant barriers to screening colonoscopy. Practice implicationsPatient reported obstacles and barriers to screening colonoscopy needs to be addressed to improve adherence.

Comparison of Advanced Colorectal Neoplasias Among Immunological Fecal Occult Blood Test (I-FOBT) Positive Group and Screening Group

G A A b st ra ct s negative predictive value was 70.7% (95% CI: 0.54-0.83). For hyperplastic polyp detection, iscan had a sensitivity of 80.5% (95% CI: 0.63-0.91) and specificity of 83.7% (95% CI: 0.73-0.91). The positive predictive value and negative predictive values were70.7% (95% CI: 0.54 -0.83) and 89.85% (95% CI: 0.79 -0.95) respectively. Conclusion: Use of i-scan as an image enhancement technique for optical diagnosis is helpful in characterizing polyps, but at this point we do not recommend the use of i-scan alone to characterize polyps. As the study the endoscopist gained experience, the accuracy of histological identification improved. There was a clear learning curve. A follow-up comparison study may show an improvement in sensitivity and specificity.

Abstract CN13-03: Next-generation stool DNA testing

Abstract CN13-03: Next-generation stool DNA testing

Evidence for colorectal cancer screening

The incidence of colorectal cancer (CRC) has been increasing during the past decades, and the lifetime risk for CRC in industrialised countries is about 5%. CRC is a good candidate for screening, because it is a disease with high prevalence, has recognised precursors, and early treatment is beneficial. This paper outlines the evidence for efficacy from randomised trials for the most commonly used CRC screening tests to reduce CRC incidence and mortality in the average-risk population. Four randomised trials have investigated the effect of guaiac-based fecal occult blood screening on CRC mortality, with a combined CRC mortality risk reduction of 15-17% in an intention-to-screen analysis, and 25% for those people who attended screening. Flexible sigmoidoscopy screening has been evaluated in three randomised trials. The observed reduction in CRC incidence varied between 23 and 80%, and between 27 and 67% for CRC mortality, respectively (intention-to-screen analyses) in the trials with long follow-up time. No randomised trials exist in other CRC screening tools, included colonoscopy screening. FOBT and flexible sigmoidoscopy are the two CRC screening methods which have been tested in randomised trials and shown to reduce CRC mortality. These tests can be recommended for CRC screening.

Analysis of deaths occurring within the Nottingham trial of faecal occult blood screening for colorectal cancer

ObjectiveTo report the causes of, and ages at, death of subjects in an English colorectal cancer screening trial.Design and settingAnalysis of 78 708 deaths occurring between 1981 and 2008, within...

S1117 Quantitative Immunochemical Fecal Occult Blood Screening Under a Colonoscopy Constraint: A Higher Cut-off Level, a Smaller Age Range or a Longer Screening Interval? A Cost-Effectiveness Analysis

Introduction: Nodal metastasis has been thought important factor to predict the prognosis of gastric cancer patient. Even nodal metastasis has been crucial for making a treatment options (surgery or endoscopy) in early gastric cancer. Thus far, nodal metastasis has been studied for associated factortumor size, cell differentiations, depth of invasions. Recent epidemiologic studies have shown a positive association between obesity and cancers. And hyperlipidemia and insulin resistance have been known as an independent risk factor for nodal metastasis of gastric cancer. Although obesity is as an independent risk factor of nodal metastasis, relevant clinical data are limited. In order to measure relation of nodal metastasis and obesity variables, this paper analyzes obesity variables including visceral and peripheral fat volume. Methods: During 5-year period, the patients who underwent gastrectomy for gastric cancer were selected. Retrospectively, we examined the patients' BMI, Cholesterols, Glucose and fat volume distribution using CT scan before gastrectomy. We analyzed the resected pathologycell type, differentiation, depth of invasion and lymph node metastasis. Result: A total of 671 patients(456 men, 215 women) were analyzed. Positive relationships existed between two groups(no meatstasis vs metastasis) in the ratio of visceral to peripheral fat volume(1.13 ±0.46 vs 1.48 ±0.97 p<0.01), only in men. No significant differences between two groups (no metastasis vs metastasis) were found in BMI, age, sex. The other relationships were negatively correlated total cholesterols, LDL and HDL. Conclusion: Our results prove the relationship between obesity and nodal metastasis in men. And the measurement of obesity should be examined fat volume by CT scan rather than measurement of weight.

Progress and Challenges in Colorectal Cancer Screening and Surveillance

Colorectal cancer is a leading cause of cancer death throughout the world. There is evidence that screening of average-risk individuals can result in mortality reduction with early cancer detection and cancer prevention by detection and removal of cancer precursor lesions. The optimal form of screening is not clear. Fecal screening tests can be performed at home at low initial cost, but current versions lack high sensitivity for cancer precursor lesions, and tests need to be repeated at regular intervals. Adherence to repeat testing for negative tests and referral for colonoscopy for positive tests are important elements of program effectiveness. Structural examinations of the colon are more invasive and may result in detection of both early cancer and cancer precursor lesions. Every screening program has advantages and limitations, but each program ultimately depends on quality and patient adherence.

Cost-effectiveness of screening for colorectal cancer in France using a guaiac test versus an immunochemical test

The aim of this study was to compare the cost and the effectiveness of two biennial fecal occult blood screening tests for colorectal cancer: a guaiac nonrehydrated test (G-FOBT) and an immunochemical test (I-FOBT) with the absence of screening. A Markov model was developed to compare these strategies in a general population of subjects aged 50 to 74 over a 20-year period. Compared with the absence of screening, G-FOBT and I-FOBT were associated with a decrease in colorectal cancer mortality of 17.4 percent and 25.2 percent, respectively. With regard to cost-effectiveness, expressed as cost per life-year gained, I-FOBT was the most effective and most costly alternative. Compared with no screening, G-FOBT and I-FOBT presented similar discounted incremental cost-effectiveness ratios: 2,739 euros and 2,819 euros respectively per life-year gained. When compared with G-FOBT, I-FOBT presented an incremental cost-effectiveness ratio of 2,988 euros per life-year gained. Sensitivity analyses showed the strong influence of the I-FOBT lead time, of the participation rate to screening for I-FOBT, and of the purchase price of the I-FOBT on the discounted incremental cost-effectiveness ratios. Compared with the absence of screening and with G-FOBT, the biennial two-stool immunochemical test can be considered a promising method for mass screening for colorectal cancer.

Differences in Colon Pathology between African Americans and Caucasians: A Retrospective Single VA Medical Center Experience

Purpose: In the United States, African Americans (AA) have the highest incidence and mortality from colorectal cancer (CRC) of any racial group. Several studies have shown that AA have predisposition for right-sided (proximal) CRC but there are few studies, which have compared polyp distribution and tumor biology between AA and Caucasians (C)in an equal access setting. We investigated any differences in polyp distribution and characteristics (histology, morphology, size, number) that could explain the proximal distribution and higher mortality associated with colorectal cancer in AA compared with C. Methods: We conducted a retrospective study at Jerry L. Pettis Veterans Medical Center. The charts were reviewed of all veterans who had screening flexible sigmoidoscopy, positive fecal occult blood testing or screening colonoscopy from year 2003 to 2008. Data was collected on 1,678 veterans (either C or AA) out of whom 1,366 patients were included; patients who had cancer or “polyps” with normal histology were excluded from the analysis. Chi-square test and student's t-test were used to compare variables. Right-sided polyps were defined as those being proximal to the splenic flexure and left sided polyps were distal to splenic flexure.TableResults: On colonoscopy, 45% of AA had proximal polyps compared to 29% of C (p=0.0003). 12% of AA had hyperplastic polyps compared to 19% of C (p=0.03). Also, 22% of AA had polyps with villous histology as compared to 16% of C (p=0.04). There was no difference in tubular adenomas or polyps with high-grade dysplasia. Conclusion: Right sided colon polyps are 1.7 times more common in AA than C. AA have fewer hyperplastic lesions and 1.4 times more villous polyp histology than C. African Americans should preferably undergo colonoscopy for colon cancer screening and not just flexible sigmoidoscopy even in an equal access system.

Members of the public spread word about faecal occult blood screening tests

Members of the public spread word about faecal occult blood screening tests Irish Cancer Society: Cash for bowel screen Soluble fibre only recommended in irritable bowel syndrome

Identification of colorectal adenomas by a quantitative immunochemical faecal occult blood screening test depends on adenoma characteristics, development threshold used and number of tests performed

Faecal occult blood tests (FOBT) are faulted by low sensitivity for advanced adenomatous polyps (AAP). Quantified, immunochemical, haemoglobin (Hb)-specific immunochemical FOBT (I-FOBT) measurements are now used for colorectal screening. To correlate adenoma characteristics to amount of faecal Hb lost and to evaluate sensitivity and specificity for AAP by faecal Hb development threshold used and number of I-FOBTs collected. Three daily I-FOBTs were collected and analysed in 1221 patients scheduled for colonoscopy. Faecal Hb was analysed as ngHb/mL of buffer and the highest result related to colonoscopy findings. In 1204 patients without cancer, colonoscopy identified adenomas in 294, 99 with AAPs. Adenoma patients had elevated faecal Hb increasing with advanced histology, size, pedunculated shape and multiplicity (P < 0.001 for all). At 50 ngHb/mL threshold, sensitivity and specificity for AAPs were 54.5% (95%CI 44.7, 64.7) and 88.1% (95%CI 86.2, 90.1) for three tests. At higher thresholds, sensitivity decreased, but was significantly higher with more samples collected. Conversely, specificity increased at higher thresholds, but decreased with more samples. Faecal Hb loss from adenomas is significantly associated with size, number and advanced features. Sensitivity and specificity for AAPs are determined by test threshold chosen and number of samples collected; these determine the number of colonoscopies needed for positive tests.