Immunological Fecal Occult Blood Test Research Articles

Predictive values of an immunological fecal occult blood test for the diagnosis of colorectal cancer compared using colonoscopy in symptomatic patients in Yaounde (Cameroon)

IntroductionThe predictive value of immunological fecal occult blood (iFOB) testing for the screening of colorectal cancer has been well described in the Western world. However, its relevance in Sub-Saharan Africa (SSA) is not well evaluated. It could be altered by the other causes of lower gastrointestinal bleeding such as parasitic infections. The aim of this study was to highlight the performance of an iFOB test for the prediction of colorectal cancer (CRC) during colonoscopy in SSA.MethodologyWe conducted an analytical cross-sectional study in two digestive endoscopic centers of Yaoundé (Cameroon) from the 1st July to the 31 November 2022. Patients presenting with an indication for colonoscopy without any overt gastrointestinal bleeding were included. Sociodemographic and clinical data were collected. All consenting patients underwent a qualitative immunologic occult test through the iFOB test before colonoscopy. Data were analyzed using SPSS version 23.0 software. The performance of the iFOB test for the diagnosis of CRC during colonoscopy was evaluated in terms of sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV).ResultsWe included 103 patients during the study period with a male predominance and a sex ratio of 1.7. The median age [IQR] was 52 [38—65] years (range 1 – 84 years). The most common colonoscopic lesions were polyps in 23 patients (22.3%), CRC in 17 patients (16.5%) and hemorrhoids in 15 patients (14.6%). Patients testing positive for iFOB test accounted for 43.7% (45 patients). Among these patients, 31.1% (14 patients) had a CRC. The Se of the occult blood test for CRC detection was calculated to be 82.3% (95%CI: 56.7—96.2); the Sp was 63.9% (95% CI: 53—74); the PPV was 31.1% (95% CI: 24—39) and the NPV was 94.8% (95% CI: 86.6—98.1).ConclusionThe iFOB test has a good NPV, but a poor PPV for the diagnosis of CRC in our study.

Feasibility of Support by Family Practitioners in Reducing Colorectal Cancer-Related Death among Outpatients Who Have Not Undergone Colorectal Cancer Screening.

We aimed to clarify the effectiveness of interventions in outpatients who did not undergo colorectal cancer (CRC) screening. From September 2012 to August 2013, we conducted a project, which showed that the immunological fecal occult blood test (FOBT) was actively recommended for outpatients who were ≥40 years of age, attended the Marumori Hospital regularly, and were not screened for CRC in the previous two years. We evaluated the detection rate of CRC and the disease specific survival ratio in February 2021 among patients with positive FOBT results during the retrospective cohort study. Overall, 388 (91%) out of the 425 outpatients submitted their stool samples. Among 388 outpatients, 66 tested positive for FOBT. While both the positive rate of FOBT and the detection rate of CRC (17% and 0.77%, respectively) were significantly higher than those in the nationwide administrative examination (5.7% and 0.13%, respectively) (p < 0.05), there was no statistically significant difference in the detection rate, compared with the group aged 65 years and older in the nationwide administrative examination. The 7-year CRC-specific survival ratio was 98.5%. Active promotion of FOBT at primary care institutions for outpatients who did not undergo CRC screening may contribute to reducing the frequency of CRC-related deaths.

Low potency of fecal immunological surveillance testing soon after negative colonoscopy or resection of low-risk adenoma in average-risk patients.

Postcolonoscopy surveillance colonoscopy based on positive fecal occult blood testing (FOBT) is often performed, although its long-term efficacy has not been established. The aim of this study was to clarify the low potency of FOBT surveillance at short intervals after colonoscopy. Colonoscopy was performed in 1308 average-risk patients, based on positive results of immunological FOBT [fecal immunological test (FIT)]. Patients were stratified according to the length of time since their last colonoscopy and their colonoscopy results [no adenoma or 1-2 small (<10 mm) adenomas]. Tumor detection rates were determined. The baseline patients characteristics did not differ between the groups. The advanced lesion detection rate (ALDR) among the patients who had never undergone a colonoscopy was 21.9% [95% confidence interval (CI), 19.1-25.0%]. Among the patients who had no adenoma detected in the previous colonoscopy within the past 5 years, the past 5-10 years and over 10 years, the ALDRs were 2.5% (95% CI, 1.0-5.5%), 4.1% (95% CI, 1.5-9.4%) and 9.3% (95% CI, 3.1-22.2%), respectively. Among the patients who had 1-2 small adenomas, the ALDRs were 7.4% (95% CI, 3.4-14.8%), 12.1% (95% CI, 4.2-27.9%) and 27.8% (95% CI, 12.2-51.2%), respectively. Invasive cancer was not observed in any patients within 5 years since the prior colonoscopy. In average-risk patients whose prior colonoscopy detected no adenomas or low-risk adenomas, postcolonoscopy surveillance by FIT has a low positive predictive value within a 5-year interval.

Fecal occult blood test for colorectal cancer screening

Screening programs for colorectal cancer (CRC) are standard in most developed countries because they reduce mortality and are cost-effective. Within them, colonoscopy allows to directly visualize the colon and remove neoplastic lesions. However, it is an expensive exam with low adherence in asymptomatic individuals. The fecal occult blood test (FOBT) is a low-cost and risk-free method for the user, which results in a high rate of adherence, explaining its use in most screening programs. This article analyzes the effectiveness of different fecal occult blood tests in screening programs. The main conclusions are that the sensitivity of the guaiac-based chemical test for the detection of colorectal cancer is lower than that observed with qualitative and quantitative immunological tests. Automated quantitative methods allow objective readings independent of the operator and the reaction reading time, necessary for the analysis of large numbers of samples. The participation rate with immunological FOBTs is higher than with chemical ones, which is why they are preferred by the different countries that have screening programs. The use of quantitative tests allows stratification of symptomatic and asymptomatic patients at higher risk, in the screening programs.

The Effects of Differing Invitation Models on the Uptake of Immunological Fecal Occult Blood Testing.

Participation rates in colorectal cancer screening in Germany are low. We therefore investigated the effectiveness of different invitation models for immunological stool blood tests (fecal immunological tests, FITs). A randomized controlled trial in 50- to 54-year-old clients of the health insurance provider AOK Baden-Wuerttemberg. A total of 17 532 insured persons were randomized to receive: (A) an invitation letter including a FIT (n = 5850); (B) an invitation letter including an option to request a FIT (n = 5844); or (C) an invitation letter only (n = 5838; control group, routine practice). Reminder letters were sent to half the members of groups A and B, selected at random, after 4 weeks. The primary endpoint was the use of a FIT within 1 year of the date of the invitation letter. IRRID: RR2-10.2196/16413. Registration: DRKS00011858. The invitation letter with a FIT enclosed (A) increased usage from 10% to 29.7% compared with the control group (+19.7% points, p < 0.0001; men: +19.4%, women: +18.8%). The invitation letter with a FIT request option (B) increased usage from 10% to 27.7% (+17.7% points, p < 0.0001; men: +17.7%, women: +17.4%). Reminders increased usage in group A by 7.5% points and in group B by 8.5% points. Participation among women was higher than among men in all groups. The FIT positivity rate was 6.9%. A subsequent colonoscopy was reported for 64.3% of FIT-positive participants, and advanced neoplasia was found in 21.3% of these cases. Letters of invitation that include a FIT and those that offer low-threshold access to a FIT achieve strong, comparable increases in the usage of FIT in the context of colorectal cancer screening.

Detection of Colorectal Cancer and Advanced Adenoma by Liquid Biopsy (Decalib Study): The ddPCR Challenge.

Background: In most countries, participation in colorectal cancer (CRC) screening programs with the immunological fecal occult blood test (iFOBT) is low. Mutations of RAS and BRAF occur early in colorectal carcinogenesis and “liquid biopsy” allows detection of mutated circulating tumor DNA (ctDNA). This prospective study aims to evaluate the performance of RAS and BRAF-mutated ctDNA in detecting CRC and advanced adenomas (AA). Methods: One hundred and thirty patients who underwent colonoscopy for suspicion of colorectal lesion were included and divided into four groups: 20 CRC, 39 AA, 31 non-advanced adenoma and/or hyperplastic polyp(s) (NAA) and 40 with no lesion. Mutated ctDNA was analyzed by droplet digital PCR. Results: ctDNA was detected in 45.0% of CRC, in 2.6% of AA and none of the NAA and “no-lesion” groups. All patients with stage II to IV mutated CRC had detectable ctDNA (n = 8/8). Among the mutated AA, only one patient had detectable ctDNA (4.3%), maybe due to limited technical sensitivity or to a low rate of ctDNA or even the absence ctDNA in plasma. Specificity and sensitivity of KRAS- and BRAF-mutated ctDNA for the detection of all CRC and AA were 100% and 16.9%, respectively. Conclusions: ctDNA had high sensitivity in detection of advanced mutated CRC but was unable to sensitively detect AA. ctDNA analysis was easy to perform and readily accepted by the population but requires combination with other circulating biomarkers before replacing iFOBT.

Health economic evidence for colorectal cancer screening programs in China: an update from 2009-2018

Objective: This study was to systematically update the economic evaluation evidence of colorectal cancer screening in mainland China. Methods: Based on a systematic review published in 2015, we expanded the scope of retrieval database (PubMed, EMbase, The Cochrane Library, Web of Science, CNKI, Wanfang Data, VIP, CBM) and extended it to December 2018. Focusing on the evidence for nearly 10 years (2009-2018), basic characteristics and main results were extracted. Costs were discounted to 2017 using the consumer price index of medical and health care being provided to the residents, and the ratio of incremental cost-effectiveness ratio (ICER) to per capita GDP in corresponding years were calculated. Results: A total of 12 articles (8 new ones) were included, of which 9 were population-based (all cross-sectional studies) and 3 were model-based. Most of the initial screening age was 40 years (7 articles), and most of the frequency was once in a lifetime (11 articles). Technologies used for primary screening included: questionnaire assessment, immunological fecal occult blood test (iFOBT) and endoscopy. The most commonly used indicator was the cost per colorectal cancer detected, and the median (range) of the 20 screening schemes was 52 307 Chinese Yuan (12 967-3 769 801, n=20). The cost per adenoma detected was 9 220 Yuan (1 859-40 535, n=10). In 3 articles, the cost per life year saved (compared with noscreening) was mentioned and the ratio of ICER to GDP was 0.673 (-0.013-2.459, n=11), which was considered by WHO as "very cost-effective" ; The range of ratios overlapped greatly among different technologies and screening frequencies, but the initial age for screening seemed more cost-effective at the age of 50 years (0.002, -0.013-0.015, n=3), than at the 40 year-olds (0.781, 0.321-2.459, n=8). Conclusions: Results from the population-based studies showed that the cost per adenoma detected was only 1/6 of the cost per colorectal cancer detected, and limited ICER evidence suggested that screening for colorectal cancer was generally cost-effective in Chinese population. Despite the inconclusiveness of the optimal screening technology, the findings suggested that the initial screening might be more cost-effective at older age. No high-level evidence such as randomized controlled trial evaluation was found.

Diagnostic Value of Pyruvate Kinase Isoenzyme Type M2 in Colon Cancer Proven with Colonoscopy.

Background:Colonoscopy is the gold standard for colon cancer screening; it is also associated with a high cost and complication. Proliferating cells, in particular tumor cells, express a dimeric isoenzyme of pyruvate kinase, termed M2 pyruvate kinase (M2-PK). The aim of this study was to determine the diagnostic accuracy of fecal M2-PK for colon cancer.Materials and Methods:Forty-nine patients with colon cancers and 49 healthy controls were selected consecutively among individuals undergoing screening colonoscopy for various indications. The diagnosis was confirmed by histology. M2-PK measurements were done by enzyme-linked immunosorbent assay of fecal occult blood test (FOBT) and immunological FOBT (IFOBT) according to the manufacturer's instructions.Results:M2-PK > 9 (U/mL) was the best cutoff point in the detection of colon cancers. In this cutoff point, sensitivity and specificity were 87.8% and 91.8%, respectively, and accuracy was 89.8%. The sensitivity and specificity of IFOBT were 93.9% and 100%, respectively, and accuracy was 96.9%. The sensitivity and specificity of FOBT were 65.3% and 100%, respectively, and accuracy was 82.6%.Conclusion:IFOBT with high sensitivity and specificity and accuracy and low cost is the best fecal screening test. The current study suggests that fecal M2-PK can be used for high-risk colon cancer patients and negative IFOBT that refused colonoscopy as a precolonoscopy screening test.

P081 Use of immunologic fecal occult blood test as a biomarker in patients with ulcerative colitis

BACKGROUND: The use of biomarkers for the assessment of inflammatory activity is an important part of current management of Ulcerative Colitis (UC). Fecal calprotectin (FC) has shown to correlate adequately with inflammatory activity, but at an elevated cost in some countries. An immunologic fecal occult blood test (iFOBT) as used in colorectal cancer screening is clearly cheaper, and there have been initial reports about its use in UC. The aim of this study was to determine the diagnostic performance of iFOBT for the assessment of inflammatory activity in UC patients, and to compare it with FC. METHODS: A diagnostic, observational, analytic study was performed. UC patients who required colonoscopy were prospectively enrolled between May 2017 and May 2018. FC and iFOBT were determined simultaneously just before starting the bowel preparation for colonoscopy, and patients were asked about their type of test preference. Inflammatory activity was assessed using the Mayo endoscopic sub score, and patients with score 2 or 3 were classified as endoscopically active. In order to identify the cut-off value for iFOBT, logistic regressions and ROC curves and tables were performed, and the value was chosen in order to achieve the highest sensitivity and positive predictive value as desired for a screening test. For the analysis, FC validated standard cut-off value was used (250 mg/g). RESULTS: During the above mentioned time period, a total of 50 patients were enrolled, 26 females, with a median age of 33 years (i:19–64). In 38/50 patients (76%) endoscopic activity was observed (Mayo score 2-3). The cut-off value for iFOBT was determined in 50 ng/mL. In terms of diagnostic performance regarding inflammatory activity, iFOBT showed a sensitivity of 89.5%, a specificity of 75%, a PPV of 91.9% and a NPV of 69.2%, with a diagnostic accuracy of 86%, meanwhile, FC showed a sensitivity of 71%, a specificity of 91.7%, a PPV of 96.4%, a NPV of 50% and a diagnostic accuracy of 76%. All the patients (100%) preferred iFOBT over FC in terms of easier sample taking and safer transportation. CONCLUSION(S): The diagnostic performance of iFOBT is similar to FC. Further studies performed in a larger sample of patients including follow-up, will allow to confirm that iFOBT could be used as another biomarker for the assessment of inflammatory activity in IBD patients.

Histopathologic study from a colorectal cancer screening in Chile: results from the first 2 years of an international collaboration between Chile and Japan

A national colorectal cancer (CRC) screening program began in Chile in 2012, which is an international collaboration between Japan and Chile and is based on a standardized protocol supported by Tokyo Medical and Dental University. We describe the results from the first 2 years of screening at one public hospital in Punta Arenas, Chile. Of 4124 asymptomatic individuals aged between 50 and 75 years, 485 participants with immunological fecal occult blood test values of at least 100 ng/ml and/or those with family histories of CRC underwent colonoscopies. Lesions were found in 291 participants, and 642 histologic samples were obtained. Chilean pathologists made the initial histologic diagnoses, and a Japanese pathologist reviewed the histologic slides and analyzed the results. Of the 291 participants with lesions, 60 (20.6%) were diagnosed with adenocarcinomas, of which 50 (83.3%) were early-phase adenocarcinomas (pTis or pT1), and 163 (56.0%) were diagnosed with conventional adenomas, of which 96 (58.9%) were high-risk adenomas. The cancer prevalence within the screened population was 1.5% (60 of 4124). The colonoscopy cancer detection rate was 12.4% (60 of 485). Notably, we detected one flat-depressed (0-IIc) lesion that measured 5 mm and had invaded the submucosa. The findings from this screening program are the first to show the histopathologic distributions of consecutive lesions and the high incidence of CRC in Chile. The high detection rates for high-risk adenomas and cancer support the feasibility of early CRC screening and its potential to reduce the mortality associated with CRC.

Mo1636 – The Addition of Other Faecal Biomarkers to Immunological Faecal Occult Blood Test is Not Effective to Avoid Normal Colonoscopies in a Colorectal Cancer Screening Program

Mo1636 – The Addition of Other Faecal Biomarkers to Immunological Faecal Occult Blood Test is Not Effective to Avoid Normal Colonoscopies in a Colorectal Cancer Screening Program

Screening individuals’ experiences of colonoscopy and colon capsule endoscopy; a mixed methods study

Background: The standard investigation in colorectal cancer screening (optical colonoscopy [OC]) has a less invasive alternative with the colon capsule endoscopy (CCE). The experiences of screening individuals are needed to support a decision aid (DA) and to provide a patient view in future health technology assessments (HTA). We aimed to explore the experiences of CCE at home and OC in an outpatient clinic by screening participants who experienced both investigations on the same bowel preparation.Methods: In a mixed methods study, Danish screening individuals with a positive immunological fecal occult blood test (FIT) were consecutively included and underwent both CCE and OC in the same bowel preparation. They answered questionnaires about discomfort during CCE, delivered at home, and during a following OC in the outpatient clinic. Data were calculated in percentages and Wilcoxon signed rank test was used for comparisons. Among the 253 included patients, 10 participants were selected for a semi-structured interview about their experiences of the two examinations. The analysis and interpretation of the transcribed data were inspired by Ricoeur.Results: Questionnaire data were received from 239 participants and revealed significant less discomfort during the CCE than the OC. Interview data included explained discomfort elements in two categories: ‘The examination’ and ‘The setting’. Compared to OC, the CCE was experienced with less pain, embarrassment and invasiveness, but presented challenges and disadvantages as well, i.e., a large camera capsule to swallow, a longer waiting time for test results after CCE and an additional OC, if pathologies were found. The home setting for CCE delivery made the participants feel less like they were ill or patients less restricted and that they received more personal care, but could induce technical challenges.Conclusion: In screening individuals, CCE at home was associated with significantly less discomfort compared to OC at a hospital, and multiple reasons for this was identified.

Current evidence and development of colorectal cancer screening in Germany

Colon cancer is currently the third leading cause of cancer death in men and women in Germany, with atotal of about 25,000 deaths per year. Established methods for early detection of colorectal cancer include lower gastrointestinal endoscopy and fecal occult blood testing. For both procedures, there is evidence of areduction in colorectal cancer-specific mortality and for endoscopy a reduction of colorectal cancer incidence has been shown.In Germany, the guaiac test for fecal occult blood has been offered since 1977. Additionally, screening colonoscopy has been offered since 2002 and in 2016, the guaiac test was replaced by the immunological fecal occult blood test, which has an improved diagnostic performance. Overall, participation rates have been low over the past decades and differed between men, women, and age groups.Personal invitations are expected to be sent out starting in 2019 as part of the introduction of an organized colorectal cancer screening program in Germany. The program also provides for measures to systematically monitor and improve the quality of colorectal cancer screening. It remains to be seen which effects these changes will have and whether the trend towards declining colon cancer incidence and mortality that has been observed in Germany will continue in the coming years.

Results of a multicentric colorectal cancer screening program in Chile

Colorectal Cancer Screening Programs (CRCSP) are widely accepted in developed countries. Unfortunately, financial restrictions, low adherence rate and variability on colonoscopy standardization hamper the implementation of CRCSP in developing countries. To analyze a multicentric pilot model of CRCSP in Chile. A prospective model of CRCSP was carried out in three cities, from 2012 to 2015. The model was based on CRC risk assessment and patient education. Health care personnel were trained about logistics and protocols. The endoscopy team was trained about colonoscopy standards. A registered nurse was the coordinator in each center. We screened asymptomatic population aged between 50 and 75 years. Immunological fecal occult blood test (FIT) was offered to all participants. Subjects with positive FIT underwent colonoscopy. A total of 12,668 individuals were enrolled, with a FIT compliance rate of 93.9% and 2,358 colonoscopies were performed. Two hundred and fifty high-risk adenomas and 110 cancer cases were diagnosed. One patient died before treatment due to cardiovascular disease, 74 patients (67%) underwent endoscopic resection and 35 had surgical treatment. Ninety one percent of patients had an early stage CRC (0-I-II). Among colonoscopy indicators, 80% of cases had an adequate bowel preparation (Boston > 6), cecal intubation rate was 97.7%, adenoma detection rate was 36.5%, and in 94.5% of colonoscopies, withdrawal time was adequate (> 8 min). This CRCS pilot model was associated to a high rate of FIT return and colonoscopy quality standards. Most CRCs detected with the program were treated by endoscopic resection.

The Implementation and First-Round Results of a Community-Based Colorectal Cancer Screening Program in Shanghai, China.

The incidence and mortality rate of colorectal cancer (CRC) have increased dramatically over the past 3 decades in China due to changes in lifestyle factors. Early detection and treatment guidelines for asymptomatic cases have shown to improve CRC control in developed countries. In response to these challenges, the Shanghai Municipal Government launched a community-based CRC screening program in 2012. Free initial screening, inclusive of immunochemical fecal occult blood and risk assessment (questionnaire), was provided by community health centers in Shanghai. Participants with positive results were referred to a specialist for a colonoscopy. In 2013, 828,302 Shanghai residents were registered; 97.7% (809,528) of the registrants completed initial screening. Among 180,094 initial screening-positive participants, 71,733 underwent colonoscopy. The proportion of compliance to colonoscopy was 39.8%; the proportion decreased with age and educational level. A total of 6,668 adenomas were detected, and 1,630 CRC cases were diagnosed. The CRC detection rate of the program was 201.35/100,000; among the detected CRCs, 51.6% were in stage 0-I. The screening program achieved great progress, especially on initial screening completion and CRC early stage rate, although particular intervention is still needed to improve the compliance of colonoscopy. Due to socioeconomic transitions and lifestyle changes, colorectal cancer is now becoming one of the most common cancers in developing countries, as it is in developed countries. While most developed countries have now initiated national colorectal cancer screening programs based on recommended country-specific colorectal cancer screening guidelines, colonoscopy has become the most commonly used screening method. This is a challenge in developing countries due to limited resources. Based on the analysis of the Shanghai colorectal cancer screening program, with immunological fecal occult blood test and risk assessment as initial screening, followed by a diagnostic testing of colonoscopy for individuals with positive results, this article provides the basis and suggestion for similar program in other regions of China and other developing countries.

Screening for colorectal cancer using immunological fecal occult blood test in inpatients

We investigated the usefulness of screening for colorectal cancer (CRC) using immunological fecal occult blood test (FOBT) in 472 scheduled inpatients (median age, 68.6 years) who underwent screening for CRC via FOBT (single stool sample) at our hospital. The recall rate for further examination was 26.6% (126/472), and the rate of patients who underwent further examination was only 34.9% (44/126). The overall colorectal neoplasm detection rate, overall CRC detection rate, and positive predictive value for CRC in inpatients were 5.5% (26/472), 1.4% (7/472), and 5.5% (7/126), respectively, which were higher than those of population-based screening for CRC. Screening for CRC using FOBT in inpatients is a non-invasive and efficient method to detect latent CRC.

What is the best screening strategy to detect advanced colorectal adenomas? Simulation from ongoing Italian screening experiences.

The best screening strategy for colorectal cancer is still debated. We simulated two screening strategies, namely flexible sigmoidoscopy (single episode) and immunological fecal occult blood test (FOBT) (five biennial rounds) and comparing their results as regards advanced adenomas and colorectal cancer detection. A Markov model was developed to estimate the number of advanced adenomas and colorectal cancer detected with the two compared screening strategies. Two different scenarios, namely a) where the same compliance (50%) at both flexible sigmoidoscopy and immunological FOBT invitation is applied, and b) where the actual compliance observed at a national level (immunological FOBT, 45%; flexible sigmoidoscopy, 30%) is applied. In scenario a), immunological FOBT would detect a total of 20,573 adenomas and 3,952 colorectal cancers, performing 74,507 total colonoscopies compared to 20,939 and 2,511, respectively, detected by flexible sigmoidoscopy, with 17,985 total colonoscopies. In scenario b), immunological FOBT would detect 17,845 advanced adenomas with 65,215 colonoscopies performed compared to 12,672 detected by flexible sigmoidoscopy with 10,796 colonoscopies. The probability of having a colonoscopy for a subject attending all the five immunological FOBT rounds was 15.9%. The simulation suggests that also immunological FOBT screening may achieve a substantial detection of advanced adenomas and therefore may have an impact on colorectal cancer incidence.

Factors influencing participation in colorectal cancer screening programs in Spain

To analyze the sociodemographic and organizational factors influencing participation in population-based colorectal cancer screening programs (CRCSP) in Spain, a retrospective study was conducted in a cohort of people invited to participate in the first 3 screening rounds of 6 CRCSP from 2000 to 2012. Mixed logistic regression models were used to analyze the relationship between sociodemographic and organizational factors, such as the type of fecal occult blood test (FOBT) used and the FOBT delivery type. The analysis was performed separately in groups (Initial screening-first invitation, Subsequent invitation for previous never-responders, Subsequent invitation-regular, Subsequent invitation-irregular intervals). The results showed that, in the Initial screening-first invitation group, participation was higher in women than in men in all age groups (OR 1.05 in persons aged 50–59years and OR 1.12 in those aged 60–69years). Participation was also higher when no action was required to receive the FOBT kit, independently of the type of screening (Initial screening-first invitation [OR 2.24], Subsequent invitation for previous never-responders [OR 2.14], Subsequent invitation-regular [OR 2.03], Subsequent invitation-irregular intervals [OR 9.38]) and when quantitative rather than qualitative immunological FOBT (FIT) was offered (Initial screening-first invitation [OR 0.70], Subsequent invitation for previous never-responders [OR 0.12], Subsequent invitation-regular [OR 0.20]) or guaiac testing (Initial screening-first invitation [OR 0.81], Subsequent invitation for previous never-responders [OR 0.88], Subsequent invitation-regular [OR 0.73]). In conclusion, the results of this study show that screening participation could be enhanced by inclusion of the FOBT kit with the screening invitation and the use of the quantitative FIT.

Abstract 4920: Evaluation of a diagnostic blood test for colorectal cancer screening and as a triage tool to stratify patients for colonoscopy

Abstract Worldwide, colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer death, with an annual incidence in 2012 of 1.4 million CRC cases and an annual mortality around 700,000 [1]. Fortunately the majority of colorectal cancer (CRC) cases are preventable by early detection and removal by colonoscopy or surgery. Currently in Australia, the only widely used non-invasive screening test for CRC is the immunological faecal occult blood test (iFOBT), which has been shown to reduce CRC incidence and mortality by 15-25% [2]. There are however significant issues that limit its effectiveness as a diagnostic screening tool, such as a poor positive predictive value of 5.3% for suspected cancer and low participation rate of approximately 33.5% in 2013, as seen in the Australian National Bowel Cancer Screening Program (NBCSP)[2]. Evidence indicates a robust, blood-based, diagnostic assay would increase screening participation and compliance. In our systematic analysis of 68 individual biomarkers using logistic regression strategies, we have identified a unique 3 protein biomarker panel blood test consisting of Insulin like growth factor binding protein 2 (IGFBP2), Dickkopf-3 (DKK3), and Pyruvate kinase M2(PKM2)[3]. This panel not only differentiates between CRC and normal patient sera with 95% specificity and 73% sensitivity in a single measurement (c.f. FOBT: 35-50 sensitivity [4]) but early stage disease. Currently, we are prospectively collecting a new cohort of over 1,000 blood samples from volunteers that have undergone colonoscopy, that include CRC patients, controls and other pathologies (IBD, other cancers) to specifically determine the performance of this blood test in asymptomatic and surveillance screening populations. We will also evaluate directly the accuracy and performance of our biomarker panel, as a diagnostic test suitable for CRC screening versus the iFOBT used in the NBCSP, as an intermediary test in the triage of individuals with positive iFOBT result for need and urgency to have a colonoscopy. 1. Ferlay J, Soerjomataram I, Ervik M, Dikshit R, Eser S, Mathers C, Rebelo M, Parkin DM, Forman D, Bray, F. GLOBOCAN 2012 v1.1, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11 2. National Bowel Cancer Screening Program: monitoring report 2012-2013. AIHW &amp; Australian Government Department of Health and Ageing, 2014. 3. Fung KYC et al 2015. Blood-based protein biomarker panel for the detection of colorectal cancer. PloS one. 2015;10(3):e0120425. 4. Morikawa, T et al., A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population. Gastroenterology, 2005. 129(2): p. 422-8. Citation Format: Leah J. Cosgrove, Kathy Surinya, Kim YC Fung, Ilka Priebe, Mike Buckley, Tim Adams, Bruce Tabor, Leanne Purins, Trevor Lockett, Hugo Leroux, Peter Gibbs, Jiangqin Wei, Ed Nice, Tony Burgess, Michelle Thomas, James Moore, Raj Singh, Andrew Ruszkiewicz. Evaluation of a diagnostic blood test for colorectal cancer screening and as a triage tool to stratify patients for colonoscopy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4920.

Cáncer colorrectal

EpidemiologyColorectal cancer (CRC) is the most common malignancy in Spain and the third worldwide. Approximately 80% are sporadic, 20% exhibit familial clustering and 5% occur within a well-defined hereditary syndrome. PathogenyAlthough sometimes CRC originates from a previously healthy colonic mucosa, in most cases CRC arises from malignant transformation of an adenomatous polyp. DiagnosisScreening in average-risk populations has proven to decline mortality by 30-70% and to be cost-effective. Colonoscopy is the most sensitive and specific method but its limited acceptance and high cost have positioned immunological faecal occult blood testing as the initial procedure in screening programs. TreatmentSurgery remains the most effective treatment preceded by chemoradiotherapy in locally advanced rectal cancer. Chemotherapy has been shown to improve overall survival and quality of life in stages III and IV. In this review we update the most relevant molecular, epidemiological, diagnostic and therapeutic aspects of this entity.