Diagnostic performance of guaiac-based fecal occult blood test in routine screening: state-wide analysis from Bavaria, Germany

Nurse-delivered acupressure on early postoperative gastrointestinal function among patients undergoing colorectal cancer surgery

Objective

Postoperative gastrointestinal dysfunction occurred up to 25% of patients who undergo colorectal cancer surgery, which could cause severe complications and increase economic burden. This study aims to evaluate the effectiveness of nurse-delivered acupressure on early postoperative gastrointestinal function among patients undergoing colorectal cancer surgery.

Methods

A total of 112 adult patients (≥ 18 years) scheduled to receive colorectal cancer surgery were randomized into two groups. Acupressure was practiced at ST36 for five days after operation, while the control group used gently rubbing skin. Primary outcomes were the time to first passage of flatus and defecation, while the secondary outcomes were the degree of abdominal distention and bowel motility. The Student's t-test and Mann-Whitney U test or Chi-square test and regression analyses were used, while for repeated measures of outcomes, area under the curve (AUC) was compared between groups and subgroups.

Results

After adjusting for potential confounding variables, acupressure significantly shortened the time to have first flatus passage by 11.08 ​h (95%CI: -19.36 to -2.81; P ​< ​0.01). The first passage time of defecation (mean, 77.00 ​± ​36.27 ​h vs. 80.08 ​± ​28.88 ​h), abdominal distention (AUC, 5.68 ​± ​5.24 vs. 5.92 ​± ​4.03), and bowel motility (AUC, 12.09 ​± ​4.70 vs. 11.51 ​± ​3.00) in the intervention group had some improvement although the differences were not statistically significant (P ​> ​0.05).

Conclusions

This study indicated that acupressure done by trained nurses could be an effective and feasible solution to promote early gastrointestinal function recovery among patients undergoing colorectal cancer surgery.

Trial registration

Chinese Clinical Trial Registry (ChiCTR-IOR-17012460).

Guaiac-based faecal occult blood tests versus faecal immunochemical tests for colorectal cancer screening in average-risk individuals

BACKGROUND

Worldwide, many countries have adopted colorectal cancer (CRC) screening programmes, often based on faecal occult blood tests (FOBTs). CRC screening aims to detect advanced neoplasia (AN), which is defined as CRC or advanced adenomas. FOBTs fall into two categories based on detection technique and the detected blood component: qualitative guaiac-based FOBTs (gFOBTs) and faecal immunochemical tests (FITs), which can be qualitative and quantitative. Screening with gFOBTs reduces CRC-related mortality.

OBJECTIVES

To compare the diagnostic test accuracy of gFOBT and FIT screening for detecting advanced colorectal neoplasia in average-risk individuals.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS Citation Index, Science Citation Index Expanded, and Google Scholar. We searched the reference lists and PubMed-related articles of included studies to identify additional studies.

SELECTION CRITERIA

We included prospective and retrospective studies that provided the number of true positives, false positives, false negatives, and true negatives for gFOBTs, FITs, or both, with colonoscopy as reference standard. We excluded case-control studies. We included studies in which all participants underwent both index test and reference standard ("reference standard: all"), and studies in which only participants with a positive index test underwent the reference standard while participants with a negative test were followed for at least one year for development of interval carcinomas ("reference standard: positive"). The target population consisted of asymptomatic, average-risk individuals undergoing CRC screening. The target conditions were CRC and advanced neoplasia (advanced adenomas and CRC combined).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies for inclusion. In case of disagreement, a third review author made the final decision. We used the Rutter and Gatsonis hierarchical summary receiver operating characteristic model to explore differences between tests and identify potential sources of heterogeneity, and the bivariate hierarchical model to estimate sensitivity and specificity at common thresholds: 10 µg haemoglobin (Hb)/g faeces and 20 µg Hb/g faeces. We performed indirect comparisons of the accuracy of the two tests and direct comparisons when both index tests were evaluated in the same population.

MAIN RESULTS

We ran the initial search on 25 June 2019, which yielded 63 studies for inclusion. We ran a top-up search on 14 September 2021, which yielded one potentially eligible study, currently awaiting classification. We included a total of 33 "reference standard: all" published articles involving 104,640 participants. Six studies evaluated only gFOBTs, 23 studies evaluated only FITs, and four studies included both gFOBTs and FITs. The cut-off for positivity of FITs varied between 2.4 μg and 50 µg Hb/g faeces. For each Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability than gFOBTs for AN (P < 0.001) and CRC (P = 0.004). For the detection of AN, the summary sensitivity of gFOBTs was 15% (95% confidence interval (CI) 12% to 20%), which was significantly lower than FITs at both 10 μg and 20 μg Hb/g cut-offs with summary sensitivities of 33% (95% CI 27% to 40%; P < 0.001) and 26% (95% CI 21% to 31%, P = 0.002), respectively. Results were simulated in a hypothetical cohort of 10,000 screening participants with 1% CRC prevalence and 10% AN prevalence. Out of 1000 participants with AN, gFOBTs missed 850, while FITs missed 670 (10 μg Hb/g cut-off) and 740 (20 μg Hb/g cut-off). No significant differences in summary specificity for AN detection were found between gFOBTs (94%; 95% CI 92% to 96%), and FITs at 10 μg Hb/g cut-off (93%; 95% CI 90% to 95%) and at 20 μg Hb/g cut-off (97%; 95% CI 95% to 98%). So, among 9000 participants without AN, 540 were offered (unnecessary) colonoscopy with gFOBTs compared to 630 (10 μg Hb/g) and 270 (20 μg Hb/g) with FITs. Similarly, for the detection of CRC, the summary sensitivity of gFOBTs, 39% (95% CI 25% to 55%), was significantly lower than FITs at 10 μg and 20 μg Hb/g cut-offs: 76% (95% CI 57% to 88%: P = 0.001) and 65% (95% CI 46% to 80%; P = 0.035), respectively. So, out of 100 participants with CRC, gFOBTs missed 61, and FITs missed 24 (10 μg Hb/g) and 35 (20 μg Hb/g). No significant differences in summary specificity for CRC were found between gFOBTs (94%; 95% CI 91% to 96%), and FITs at the 10 μg Hb/g cut-off (94%; 95% CI 87% to 97%) and 20 μg Hb/g cut-off (96%; 95% CI 91% to 98%). So, out of 9900 participants without CRC, 594 were offered (unnecessary) colonoscopy with gFOBTs versus 594 (10 μg Hb/g) and 396 (20 μg Hb/g) with FITs. In five studies that compared FITs and gFOBTs in the same population, FITs showed a higher discriminative ability for AN than gFOBTs (P = 0.003). We included a total of 30 "reference standard: positive" studies involving 3,664,934 participants. Of these, eight were gFOBT-only studies, 18 were FIT-only studies, and four studies combined both gFOBTs and FITs. The cut-off for positivity of FITs varied between 5 µg to 250 µg Hb/g faeces. For each QUADAS-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability for detecting CRC than gFOBTs (P < 0.001). The summary sensitivity for CRC of gFOBTs, 59% (95% CI 55% to 64%), was significantly lower than FITs at the 10 μg Hb/g cut-off, 89% (95% CI 80% to 95%; P < 0.001) and the 20 μg Hb/g cut-off, 89% (95% CI 85% to 92%; P < 0.001). So, in the hypothetical cohort with 100 participants with CRC, gFOBTs missed 41, while FITs missed 11 (10 μg Hb/g) and 11 (20 μg Hb/g). The summary specificity of gFOBTs was 98% (95% CI 98% to 99%), which was higher than FITs at both 10 μg and 20 μg Hb/g cut-offs: 94% (95% CI 92% to 95%; P < 0.001) and 95% (95% CI 94% to 96%; P < 0.001), respectively. So, out of 9900 participants without CRC, 198 were offered (unnecessary) colonoscopy with gFOBTs compared to 594 (10 μg Hb/g) and 495 (20 μg Hb/g) with FITs. At a specificity of 90% and 95%, FITs had a higher sensitivity than gFOBTs.

AUTHORS' CONCLUSIONS

FITs are superior to gFOBTs in detecting AN and CRC in average-risk individuals. Specificity of both tests was similar in "reference standard: all" studies, whereas specificity was significantly higher for gFOBTs than FITs in "reference standard: positive" studies. However, at pre-specified specificities, the sensitivity of FITs was significantly higher than gFOBTs.

Fusobacterium nucleatum and cancer

Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor‐promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor‐specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment.

Autoantibodies in the diagnosis, prognosis, and prediction of colorectal cancer

Colorectal cancer (CRC) is the second-most commonly diagnosed cancer worldwide. Early diagnosis improves prognosis and long-term outcomes. Several studies have found tumor-associated autoantibodies in CRC patients. We aimed to provide an overview on CRC-associated autoantibodies and their reported diagnostic, prognostic, and predictive performance when used singly or in combination. We systematically reviewed studies on CRC-related autoantibodies published till March 2018 and critically analyzed the role of these autoantibodies in CRC. In general, autoantibodies were of low sensitivity when tested individually and the diagnostic characteristics improved when tested in combination. Autoantibodies against CCD83, carcinoembryonic antigen, MAPKAPK3, RPH 3AL, SEC61b, and SPAG9 showed high sensitivity and specificity when tested alone. When tested in combination, autoantibodies against three antigens (PIM1, MAPKAPK3, and ACVR2B) showed high sensitivity and specificity. So far, most CRC-associated autoantibodies have been evaluated in single or in a small number of studies. In contrast, anti-p53 antibodies have been studied in a larger number of CRC studies, but, so far, none of them have high diagnostic characteristics. CRC-associated autoantibodies are detectable from the early stages of malignancy, pointing to their possible use in the early detection of CRC. Some studies suggest that CRC-associated autoantibodies may be a guide to prognosis in CRC.

Using bioinformatics approaches to investigate driver genes and identify BCL7A as a prognostic gene in colorectal cancer

Colorectal cancer (CRC) results from the uncontrolled growth of cells in the colon, rectum, or appendix. The 5-year relative survival rate for patients with CRC is 65% and is correlated with the stage at diagnosis (being 91% for stage I at diagnosis versus 12% for stage IV). This study aimed to identify CRC driver genes to assist in the design of a cancer panel to detect gene mutations during clinical early-stage screening and identify genes for use in prognostic assessments and the evaluation of appropriate treatment options. First, we utilized bioinformatics approaches to analyze 354 paired sequencing profiles from The Cancer Genome Atlas (TCGA) to identify CRC driver genes and analyzed the sequencing profiles of 38 patients with >5 years of follow-up data to search for prognostic genes. The results revealed eight driver genes and ten prognostic genes. Next, the presence of the identified gene mutations was verified using tissue and blood samples from Taiwanese CRC patients. The results showed that the set identified gene mutations provide high coverage for driver gene screening, and APC, TP53, PIK3CA, and FAT4 could be detected in blood as ctDNA test targets. We further found that BCL7A gene mutation was correlated with prognosis in CRC (log-rank p-value = 0.02), and that mutations of BCL7A could be identified in ctDNA samples. These findings may be of value in clinical early cancer detection, disease monitoring, drug development, and treatment efforts in the future.

Alterations of circulating bacterial DNA in colorectal cancer and adenoma: A proof-of-concept study

The gut microbiota is closely associated with colorectal neoplasia. While most metagenomics studies utilized fecal samples, circulating bacterial DNA in colorectal neoplasia patients remained unexplored. This proof-of-concept study aims to characterize alterations of circulating bacterial DNA in colorectal neoplasia patients. We performed WGS of plasma samples from 25 colorectal cancer (CRC) patients, 10 colorectal adenoma (CRA) patients and 22 healthy controls (HC). Bacterial relative abundance was measured by removing the host genome and mapping reads into bacterial genomes. By diversity analysis, we found plasma samples required less sample size to approach saturation than fecal samples, and species diversity in HC was slightly higher compared with CRC/CRA patients. The majority of circulating bacterial DNA came from bacterial genera which commonly associated with gastrointestine and oral tract. By differential analysis, a total of 127 significant species between CRC patients and HC were identified, on which basis 28 species with top predictive ability were selected and showed promise in preliminary discrimination between CRC/CRA and HC. In CRA patients, relative abundance of the selected 28 species more closely resembled those in CRC patients than HC. By comparing with fecal metagenomics studies, we found there was moderate positive correlation between fold changes of the overlapped fecal and circulating bacterial DNA. Finally, species correlation analysis revealed that CRC and HC displayed distinct patterns of species association. In conclusion, this study demonstrated alterations of circulating bacterial DNA in colorectal neoplasia patients, which had the potential to become non-invasive biomarkers for colorectal neoplasia screening and early diagnosis.

Sociodemographic changes in the population frequency of colonoscopy following the implementation of organised bowel cancer screening: An analysis of data from Swedish registers, 2006-2015

OBJECTIVE

To assess sociodemographic changes in the population frequency of colonoscopy (PFC; number of colonoscopies per 1000 inhabitants per year) among people aged 50-74 in relation to the implementation of a regional colorectal cancer screening programme for people aged 60-69 in the Stockholm-Gotland region (RSG) in 2008.

METHOD

The PFC was estimated by year (2006-2015), pre- and post-implementation of colorectal cancer screening programme (2006-2007 vs. 2014-2015), age, sex, residential region, immigrant status and educational level. The data were obtained from Swedish patient and population registers.

RESULTS

The PFC largely increased during 2006-2015 in all six Swedish regions. The estimated increase in the pre- vs. post period PFC (ΔPFC) within the RSG was (i) greater for men than for women (5.8 vs. 4.5) and (ii) smaller for people aged 70-74 than for those aged 60-69 (5.5 vs. 9.0), while the corresponding ΔPFCs within each of the other regions were (i) not greater, or even smaller, for men and (ii) not smaller, or even larger, for elderly people aged 70-74.

CONCLUSION

A regional implementation of an organised colorectal cancer screening programme did not lead to a higher PFC increase in the screening relevant age group 50-74 years. Nevertheless, changes in the PFC were more pronounced for men and less pronounced for people aged 70-74 than those invited to participate in the screening programme (60-69 years), as compared with the rest of Sweden (without organised colorectal cancer screening).

Sex differences in the impact of Affordable Care Act Medicaid expansion on colorectal cancer screening

Access to care varies by sex such that interactions with insurance status result in mixed patterns of preventive services utilization. We examined sex-specific effects of ACA Medicaid expansions on receipt of CRC screening. We used Behavioral Risk Factor Surveillance System data (2008-2016) for adults aged 50-64 years with household income ≤138% of federal poverty level to examine self-reported lifetime use of guideline-recommended CRC screening services overall and by screening modality. We employed difference-in-difference models comparing changes in CRC screening in 20 Medicaid expansion states before and after the ACA to changes in 18 states that did not expand Medicaid during our study period. We divided the expansion period into implementation (2014) and post-expansion (2016) periods to account for possible lagged effects. We observed time-varying effects of Medicaid expansion that revealed relative increases in CRC screening occurring during the post-expansion period. Heterogeneous effects by sex and by screening modality were also observed: there was a significant relative increase of 16.2 percentage points (95% CI [2.2, 30.2]; p-value = 0.023) in lifetime colonoscopy use among women in expansion states relative to non-expansion states in the post-expansion period. There were no significant effects of Medicaid expansion among men. Health insurance expansion had a lagged but significant effect on CRC screening among low-income non-elderly women in Medicaid expansion states, but no effect for men. The observed increase in CRC screening among women suggests that barriers to CRC screening may differ by sex, and tailored interventions to increase CRC screening improve outcomes.

Non-Invasive Colorectal Cancer Screening: An Overview

Background

Colorectal cancer (CRC) follows a protracted stepwise progression, from benign adenomas to malignant adenocarcinomas. If detected early, 90% of deaths are preventable. However, CRC is asymptomatic in its early-stage and arises sporadically within the population. Therefore, CRC screening is a public health priority.

Summary

Faecal immunochemical test (FIT) is gradually replacing guaiac faecal occult blood test and is now the most commonly used screening tool for CRC screening program globally. However, FIT is still limited by the haemoglobin degradation and the intermittent bleeding patterns, so that one in four CRC cases are still diagnosed in a late stage, leading to poor prognosis. A multi-target stool DNA test (Cologuard, a combination of NDRG4 and BMP3 DNA methylation, KRAS mutations, and haemoglobin) and a plasma SEPT9 DNA methylation test (Epi proColon) are non-invasive tools also approved by the US FDA, but those screening approaches are not cost-effective, and the detection accuracies remain unsatisfactory. In addition to the approved tests, faecal-/blood-based microRNA and CRC-related gut microbiome screening markers are under development, with work ongoing to find the best combination of molecular biomarkers which maximise the screening sensitivity and specificity.

Key Message

Maximising the detection accuracy with a cost-effective approach for non-invasive CRC screening is urgently needed to further reduce the incidence of CRC and associated mortality rates.

Analysis of the effectiveness of two noninvasive fecal tests used to screen for colorectal cancer in average-risk adults

OBJECTIVES

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Although a significant proportion of CRC cases and deaths are preventable by screening, the morbidity and mortality from CRC remains high and is attributed to suboptimal screening rates. Low levels of population CRC screening uptake may be due to reluctance toward invasiveness of some screening tests, embarrassment, exposure to anesthesia, and grueling preparation, especially for the invasive screening tests. Noninvasive tests overcome many of these barriers because they are more convenient and potentially more attractive to patients compared to invasive tests. This study uses Markov cohort simulation model developed with the help of TreeAge pro software to compare two noninvasive fecal CRC screens, fecal immunohistochemical test (FIT) and multitarget stool DNA test (Mt-sDNA) with no screening in order to identify the more effective noninvasive fecal test to screen for colorectal cancer in average-risk adults.

STUDY DESIGN

Simulation study developed with Markov model using TreeAge pro software, which included a hypothetical cohort at the average risk of developing colorectal cancer.

METHODS

Markov model was used to compare population-level CRC-related cases and deaths averted, life-years gained (LYG), and colonoscopies required for two noninvasive CRC screening strategies compared with no screening: annual fecal immunohistochemical testing (FIT) and 3-yearly multitarget stool DNA testing (Mt-sDNA). The model simulated the natural history of the adenoma-carcinoma sequence in average-risk persons starting at age 50 years, and natural history parameters were estimated from the literature and via verification to data on precancerous lesions (i.e. adenomas) and CRC incidence. Screening strategies were then superimposed on the natural history component of the model, allowing for precancerous lesions to be detected and removed, or CRC to be detected and treated at a potentially earlier stage. The sensitivity and specificity for each screen for precancerous lesions and CRC were the performance parameters used to estimate the effectiveness.

RESULTS

Annual FIT was more effective than three yearly Mt-sDNA in reducing CRC cases, averting CRC-related deaths, and increasing the LYG compared to no screening. On average, annual FIT resulted in 3.5 fewer CRC cases, and 2.9 fewer CRC deaths per 1000 persons screened compared to 3-yearly Mt-sDNA. Annual FIT usage resulted in a 0.18 LYG compared to Mt-sDNA, which allowed 0.16 LYG, and an annual FIT screening led to a total of 203 more colonoscopies performed compared to Mt-sDNA. One-way sensitivity analysis conducted over the sensitivity rates of each screen by type of lesion showed that FIT remained the more effective strategy for all ranges of sensitivity. Threshold analysis results identified the lowest FIT sensitivity value at which Mt-sDNA performed better for conventional high-risk adenomas and CRC detection to be 0.16 and 0.052, respectively.

CONCLUSION

Both the noninvasive screens were effective compared to no screening. Additionally, annual FIT as a first step noninvasive screening test for CRC appears to be more effective compared to three-yearly Mt-sDNA.

Mortality From Postscreening (Interval) Colorectal Cancers Is Comparable to That From Cancer in Unscreened Patients-A Randomized Sigmoidoscopy Trial

BACKGROUND & AIMS

Endoscopic screening for colorectal cancer (CRC) is performed at longer time intervals than the fecal occult blood test or screenings for breast or prostate cancer. This causes concerns about interval cancers, which have been proposed to progress more rapidly. We compared outcomes of patients with interval CRCs after sigmoidoscopy screening vs outcomes of patients with CRC who had not been screened.

METHODS

We performed a secondary analysis of a randomized sigmoidoscopy screening trial in Norway with 98,684 participants (age range, 50-64 years) who were randomly assigned to groups that were (n = 20,552) or were not (n = 78,126) invited for sigmoidoscopy screening from 1999 through 2001; participants were followed up for a median 14.8 years. We compared CRC mortality and all-cause mortality between individuals who underwent screening and were diagnosed with CRC 30 days or longer after screening (interval cancer group, n = 163) and individuals diagnosed with CRC in the nonscreened group (controls, n = 1740). All CRCs in the control group were identified when they developed symptoms (clinically detected CRCs). Analyses were stratified by cancer site. We used Cox regression to estimate hazard ratio (HRs), adjusted for age and sex.

RESULTS

Over the follow-up period, 43 individuals in the interval cancer group died from CRC; among controls, 525 died from CRC. CRC mortality (adjusted HR, 0.98; 95% confidence interval, 0.72-1.35; P = .92), rectosigmoid cancer mortality (adjusted HR, 1.10; 95% confidence interval, 0.63-1.92; P = .74), and all-cause mortality (adjusted HR, 0.99; 95% confidence interval, 0.76-1.27; P = .91) did not differ significantly between the interval cancer group and controls.

CONCLUSIONS

In this randomized sigmoidoscopy screening trial, mortality did not differ significantly between individuals with interval CRCs and unscreened patients with clinically detected CRCs. ClinicalTrials.gov identifier: NCT00119912.

Measurement of the IgM and IgG Autoantibody Immune Responses in Human Serum has High Predictive Value for the Presence of Colorectal Cancer

INTRODUCTION

Colorectal cancer is a major public health issue, with incidences continuing to rise owing to the growing and aging world population. Current screening strategies for colorectal cancer diagnosis suffer from various limitations, including invasiveness and poor uptake. Consequently, there is an unmet clinical need for a minimally invasive, sensitive, and specific method for detecting the presence of colorectal cancer and pre-malignant lesions.

PATIENTS AND METHODS

An indirect enzyme-linked immunosorbent assay was used to measure the primary (IgM) and secondary (IgG) adaptive humoral immune responses to a panel of previously identified cancer antigens in the sera of normal and adenoma samples, and sera from patients with colorectal cancer.

RESULTS

An optimal panel of 7 biomarkers capable of identifying patients with colorectal cancer as distinct from both normal and adenoma samples is identified. The cumulative sensitivity and specificity of the assay are 70.8% and 86.5%, respectively. The positive and negative predictive values of the cohort are 77.3% and 82.1%. This assay was not able to accurately discriminate between normal and adenoma samples. Patients whose serum was positive for the presence of anti-ICLN IgM autoantibodies had a significantly poorer 5-year survival than patients whose serum was negative (P = .004).

CONCLUSION

This study describes a novel minimally invasive enzyme-linked immunosorbent assay-based method, capable of identifying patients with colorectal cancer as distinct from both normal and adenoma samples. Patients are likely to be far more amenable to a blood-based test such as the one described herein, rather than a fecal-based test, likely leading to increased patient uptake.

Colorectal cancer screening use among insured adults: Is out-of-pocket cost a barrier to routine screening?

AIM

To describe the characteristics of adults who needed to see a doctor in the past year but could not due to the extra cost and assess the impact of limited financial resources on the receipt of routine fecal occult blood test, sigmoidoscopy, or colonoscopy for colon cancer screening among insured patients.

METHODS

Data obtained from the 2012 Behavioral Risk Factor Surveillance System included 215436 insured adults age 50-75 years. We computed frequencies, adjusted odds ratios (aORs), and 95%CIs using SAS v9.3 software.

RESULTS

Nine percent of the study population needed to see a doctor in the past year but could not because of cost. The numbers were significantly higher among those aged 50-64 (P < 0.0001), Non-Hispanic Whites (P < 0.0001), and those with a primary care physician (P < 0.0001) among other factors. Adjusting for possible confounders, aORs for not seeing the doctor in the past year because of cost were: stool occult blood test within last year aOR = 0.88; 95%CI: 0.76-1.02, sigmoidoscopy within last year aOR = 0.72; 95%CI: 0.48-1.07, colonoscopy within the last year aOR = 0.91; 95%CI: 0.81-1.02.

CONCLUSION

We found that the limited financial resources within the past 12 mo were significantly associated with colorectal cancer (CRC) non-screening. Patients with risk factors identified in this study should adhere to CRC guidelines and should receive financial help if needed.

Colorectal cancer screening use among insured adults: Is out-of-pocket cost a barrier to routine screening?

AIM

To describe the characteristics of adults who needed to see a doctor in the past year but could not due to the extra cost and assess the impact of limited financial resources on the receipt of routine fecal occult blood test, sigmoidoscopy, or colonoscopy for colon cancer screening among insured patients.

METHODS

Data obtained from the 2012 Behavioral Risk Factor Surveillance System included 215436 insured adults age 50-75 years. We computed frequencies, adjusted odds ratios (aORs), and 95%CIs using SAS v9.3 software.

RESULTS

Nine percent of the study population needed to see a doctor in the past year but could not because of cost. The numbers were significantly higher among those aged 50-64 (P < 0.0001), Non-Hispanic Whites (P < 0.0001), and those with a primary care physician (P < 0.0001) among other factors. Adjusting for possible confounders, aORs for not seeing the doctor in the past year because of cost were: stool occult blood test within last year aOR = 0.88; 95%CI: 0.76-1.02, sigmoidoscopy within last year aOR = 0.72; 95%CI: 0.48-1.07, colonoscopy within the last year aOR = 0.91; 95%CI: 0.81-1.02.

CONCLUSION

We found that the limited financial resources within the past 12 mo were significantly associated with colorectal cancer (CRC) non-screening. Patients with risk factors identified in this study should adhere to CRC guidelines and should receive financial help if needed.

Circulating tumor DNA in patients with colorectal adenomas: assessment of detectability and genetic heterogeneity

Improving early detection of colorectal cancer (CRC) is a key public health priority as adenomas and stage I cancer can be treated with minimally invasive procedures. Population screening strategies based on detection of occult blood in the feces have contributed to enhance detection rates of localized disease, but new approaches based on genetic analyses able to increase specificity and sensitivity could provide additional advantages compared to current screening methodologies. Recently, circulating cell-free DNA (cfDNA) has received much attention as a cancer biomarker for its ability to monitor the progression of advanced disease, predict tumor recurrence and reflect the complex genetic heterogeneity of cancers. Here, we tested whether analysis of cfDNA is a viable tool to enhance detection of colon adenomas. To address this, we assessed a cohort of patients with adenomas and healthy controls using droplet digital PCR (ddPCR) and mutation-specific assays targeted to trunk mutations. Additionally, we performed multiregional, targeted next-generation sequencing (NGS) of adenomas and unmasked extensive heterogeneity, affecting known drivers such as APC, KRAS and mismatch repair (MMR) genes. However, tumor-related mutations were undetectable in patients' plasma. Finally, we employed a preclinical mouse model of Apc-driven intestinal adenomas and confirmed the inability to identify tumor-related alterations via cfDNA, despite the enhanced disease burden displayed by this experimental cancer model. Therefore, we conclude that benign colon lesions display extensive genetic heterogeneity, that they are not prone to release DNA into the circulation and are unlikely to be reliably detected with liquid biopsies, at least with the current technologies.

Detection of colorectal neoplasia: Combination of eight blood-based, cancer-associated protein biomarkers

Serological biomarkers may be an option for early detection of colorectal cancer (CRC). The present study assessed eight cancer-associated protein biomarkers in plasma from subjects undergoing first time ever colonoscopy due to symptoms attributable to colorectal neoplasia. Plasma AFP, CA19-9, CEA, hs-CRP, CyFra21-1, Ferritin, Galectin-3 and TIMP-1 were determined in EDTA-plasma using the Abbott ARCHITECT® automated immunoassay platform. Primary endpoints were detection of (i) CRC and high-risk adenoma and (ii) CRC. Logistic regression was performed. Final reduced models were constructed selecting the four biomarkers with the highest likelihood scores. Subjects (N = 4,698) were consecutively included during 2010-2012. Colonoscopy detected 512 CRC patients, 319 colonic cancer and 193 rectal cancer. Extra colonic malignancies were detected in 177 patients, 689 had adenomas of which 399 were high-risk, 1,342 had nonneoplastic bowell disease and 1,978 subjects had 'clean' colorectum. Univariable analysis demonstrated that all biomarkers were statistically significant. Multivariate logistic regression demonstrated that the blood-based biomarkers in combination significantly predicted the endpoints. The reduced model resulted in the selection of CEA, hs-CRP, CyFra21-1 and Ferritin for the two endpoints; AUCs were 0.76 and 0.84, respectively. The postive predictive value at 90% sensitivity was 25% for endpoint 1 and the negative predictive value was 93%. For endpoint 2, the postive predictive value was 18% and the negative predictive value was 97%. Combinations of serological protein biomarkers provided a significant identification of subjects with high risk of the presence of colorectal neoplasia. The present set of biomarkers could become important adjunct in early detection of CRC.

Assessing global transitions in human development and colorectal cancer incidence

Colorectal cancer incidence has paralleled increases in human development across most countries. Yet, marked decreases in incidence are now observed in countries that have attained very high human development. Thus, in this study, we explored the relationship between human development and colorectal cancer incidence, and in particular assessed whether national transitions to very high human development are linked to temporal patterns in colorectal cancer incidence. For these analyses, we utilized the Human Development Index (HDI) and annual incidence data from regional and national cancer registries. Truncated (30-74 years) age-standardized incidence rates were calculated. Yearly incidence rate ratios and HDI ratios, before and after transitioning to very high human development, were also estimated. Among the 29 countries investigated, colorectal cancer incidence was observed to decrease after reaching the very high human development threshold for 12 countries; decreases were also observed in a further five countries, but the age-standardized incidence rates remained higher than that observed at the threshold. Such declines or stabilizations are likely due to colorectal cancer screening in some populations, as well as varying levels of exposure to protective factors. In summary, it appears that there is a threshold at which human development predicts a stabilization or decline in colorectal cancer incidence, though this pattern was not observed for all countries assessed. Future cancer planning must consider the increasing colorectal cancer burden expected in countries transitioning towards higher levels of human development, as well as possible declines in incidence among countries reaching the highest development level.

Screening colonoscopy volume and detection of colorectal neoplasms: a state-wide study from Bavaria, Germany

Screening colonoscopy enables early detection of colorectal cancer and its precancerous lesions. The aim of this study was to assess the association of screening colonoscopy volume with colorectal neoplasm detection rate in routine practice. A registry-based study of individuals aged at least 55 years who underwent screening colonoscopy in Bavaria, Germany, between 2007 and 2009 was performed. Colorectal neoplasm detection rates (95% confidence intervals) were determined per physician. Physicians were grouped according to the number of screening colonoscopies performed per year (<50, 50-99, 100-199, ≥200). A total of 203 363 individuals (median age 64 years, 55.2% women) underwent screening colonoscopy between 2007 and 2009. Colonoscopies were performed by 509 physicians. The detection rate of any neoplasm increased with screening colonoscopy volume from 21.9% among physicians conducting fewer than 50 screening colonoscopies per year to 27.5% among physicians conducting 200 or more screening colonoscopies per year (P-value for trend <0.0001). Increases in detection rates with colonoscopy volume were also observed for advanced neoplasms and for colorectal cancer (P-value for trend 0.16 and <0.0001, respectively). Differences were largest between physicians conducting fewer than 50 screening colonoscopies per year and other physicians. These results support a potential role of a minimum colonoscopy volume for high-quality colonoscopy screening. Differences in neoplasm detection rates were high between physicians conducting fewer than 50 screening colonoscopies per year and physicians with higher screening colonoscopy volume.

Colorectal cancer screening: a global overview of existing programmes

Colorectal cancer (CRC) ranks third among the most commonly diagnosed cancers worldwide, with wide geographical variation in incidence and mortality across the world. Despite proof that screening can decrease CRC incidence and mortality, CRC screening is only offered to a small proportion of the target population worldwide. Throughout the world there are widespread differences in CRC screening implementation status and strategy. Differences can be attributed to geographical variation in CRC incidence, economic resources, healthcare structure and infrastructure to support screening such as the ability to identify the target population at risk and cancer registry availability. This review highlights issues to consider when implementing a CRC screening programme and gives a worldwide overview of CRC burden and the current status of screening programmes, with focus on international differences.

Identification of physicians with unusual performance in screening colonoscopy databases: a Bayesian approach

BACKGROUND

The adenoma detection rate (ADR) is an important surrogate measure of performance quality for screening colonoscopies.

OBJECTIVE

To demonstrate how physicians with unusual performance concerning the adenoma detection rate may be identified in screening colonoscopy databases.

DESIGN

Bayesian random-effects modeling and Winsorization of potential outliers were applied to develop a robust model for the majority of providers. Divergence was assessed with adjustment for multiple testing. The steps in the analysis were visualized by using funnel plots. Additionally, minimum requirements for the number of colonoscopies with 1 or more detected adenomas were derived.

SETTING

Data from 422 physicians offering screening colonoscopy and participating in a quality assurance program in Bavaria, Germany, were used.

PATIENTS

A total of 69,738 asymptomatic individuals 55 to 79 years of age.

INTERVENTION

Screening colonoscopy.

MAIN OUTCOME MEASUREMENTS

Physician-specific ADRs.

RESULTS

The overall ADR in the sample was 26%. From an initial model, 62 physicians (15%) were identified as potential outliers. A model with normally distributed random effects was then chosen as the robust null model. Of the potential outliers, 10 (16%) were confirmed as physicians with unusual performance at a false discovery rate of 5%. For all of them, the observed ADR was lower than expected, and together they accounted for 1.4% of all included colonoscopies.

LIMITATIONS

Analysis of routine data.

CONCLUSION

The applied statistical approach appears suitable to identify unusual performance in screening colonoscopy databases. Its application may help to evaluate and improve the quality of colonoscopy in population-based colorectal cancer screening programs.

Which adenomas are detected by fecal occult blood testing? A state-wide analysis from Bavaria, Germany

Guaiac-based fecal occult blood tests (gFOBTs) are the most widely used noninvasive tests for colorectal cancer screening. While it is well known that they detect only a minority of colorectal adenomas, evidence for the characteristics of adenomas associated with detection is sparse. We derived estimates of the positive likelihood ratio (LR+), a summary measure of diagnostic performance, according to adenoma characteristics by comparing findings at colonoscopy among 19,208 and 181,128 participants who underwent colonoscopy to follow-up a positive gFOBT and as a primary screening examination, respectively, in Bavaria, Germany, in 2007-2009. Age and sex-adjusted estimates of LR+ (95% confidence intervals, 95% CI) ranged from 1.09 (1.05-1.13) for adenomas <1 cm to 2.52 (2.30-2.75) for adenomas >2 cm, and were much higher for pedunculated adenomas (1.96, 95% CI 1.85-2.08) than for flat or sessile adenomas (1.11, 95% CI 1.02-1.21 and 1.12, 95% CI 1.08-1.16, respectively). Villous or tubulovillous structure and dysplasia were likewise associated with a higher chance to be detected by gFOBT. Diagnostic performance was worse for proximal than for distal adenomas (age and sex adjusted LR+:1.16, 95% CI 1.09-1.23 and 1.35, 95% CI 1.29-1.41, respectively) which was explained by the lower proportions of large, pedunculated and nontubular adenomas in the proximal colon. Size, pedunculated shape, and nontubular histology are the key determinants of detection which also explain lower detection rates of adenomas located in the proximal colon.