Canadian Association of Gastroenterology position statement on screening individuals at average risk for developing colorectal cancer: 2010. Can J Gastroenterol. 2010;24:705-714. [PMID: 21165377 DOI: 10.1155/2010/683171]

Comparative Performance of Common Fecal Immunochemical Tests : A Cross-Sectional Study

BACKGROUND

Despite widespread use of fecal immunochemical tests (FITs) for colorectal cancer (CRC) screening, data to guide test selection are limited.

OBJECTIVE

To compare the performance characteristics of 5 commonly used FITs, using colonoscopy as the reference standard.

DESIGN

Cross-sectional study. (ClinicalTrials.gov: NCT03264898).

SETTING

Three U.S. academic medical centers and affiliated endoscopy units.

PARTICIPANTS

Patients aged 50 to 85 years undergoing screening or surveillance colonoscopy.

INTERVENTION

Participants completed 5 different FITs before their colonoscopy, including 4 qualitative tests (Hemoccult ICT, Hemosure iFOB, OC-Light S FIT, QuickVue iFOB) and 1 quantitative test (OC-Auto FIT, which was run at the manufacturer's threshold for positivity of >100 ng/mL).

MEASUREMENTS

The primary outcome was test performance (sensitivity and specificity) for each of the 5 FITs for advanced colorectal neoplasia (ACN), defined as advanced polyps or CRC. Positivity rates, positive and negative predictive values, and rates of unevaluable tests were compared. Multivariable models were used to identify factors affecting sensitivity.

RESULTS

A total of 3761 participants were enrolled, with a mean age of 62.1 years (SD, 7.8); 63.2% of participants were female, 5.7% were Black, 86.4% were White, and 28.7% were Hispanic. There were 320 participants with ACN (8.5%), including 9 with CRC (0.2%). The test positivity rate varied 4-fold (3.9% to 16.4%) across FITs. Rates of unevaluable FITs ranged from 0.2% to 2.5%. The sensitivity for ACN varied from 10.1% to 36.7%, and specificity varied from 85.5% to 96.6%. Differences in sensitivity between FITs were all statistically significantly different except between Hemosure iFOB and QuickVue iFOB, and specificity differences were all statistically significantly different from one another. In addition to FIT brand, distal location of ACN was also associated with higher FIT sensitivity.

LIMITATION

The study did not assess the programmatic sensitivity of annual FIT.

CONCLUSION

Although considered a single class, FITs have varying test performance for detecting ACN and should not be considered interchangeable.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Optimizing Timing of Follow-Up Colonoscopy: A Pilot Cluster Randomized Trial of a Knowledge Translation Tool

BACKGROUND

Endoscopists have low adherence to guideline-recommended colonoscopy surveillance intervals. We performed a cluster-randomized single-blind pilot trial in Winnipeg, Canada, to assess the effectiveness of a newly developed digital application tool that computes guideline-recommended follow-up intervals.

METHODS

Participant endoscopists were randomized to either receive access to the digital application (intervention group) or not receive access (control group). Pathology reports and final recommendations for colonoscopies performed in the 1-4 months before randomization and 3-7 months postrandomization were extracted. Generalized estimating equation models were used to determine whether the access to the digital application predicted guideline congruence.

RESULTS

We included 15 endoscopists in the intervention group and 14 in the control group (of 42 eligible endoscopists in the city), with 343 patients undergoing colonoscopy before randomization and 311 postrandomization. Endoscopists who received the application made guideline-congruent recommendations 67.6% of the time before randomization and 76.1% of the time after randomization. Endoscopists in the control group made guideline-congruent recommendations 72.4% and 72.9% of the time before and after randomization, respectively. Endoscopists in the intervention group trended to have an increase in guideline adherence comparing postintervention with preintervention (odds ratio [OR]: 1.50, 95% confidence interval [CI] 0.82-2.74). By contrast, the control group had no change in guideline adherence (OR: 1.07, 95% CI 0.50-2.29). Endoscopists in the intervention group with less than median guideline congruence prerandomization had a significant increase in guideline-congruent recommendations postrandomization.

DISCUSSION

An application that provides colonoscopy surveillance intervals may help endoscopists with guideline congruence, especially those with a lower preintervention congruence with guideline recommendations ( ClincialTrials.gov number, NCT04889352).

Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Time Trends in Colorectal Cancer Incidence From 1992 to 2016 and Colorectal Cancer Mortality From 1980 to 2018 by Age Group and Geography in Canada

INTRODUCTION

Several reports have highlighted increasing colorectal cancer (CRC) incidence among younger individuals. However, little is known about variations in CRC incidence or mortality across age subgroups in different geographical locations. We aimed to examine time trends in CRC incidence and mortality in Canada by age group and geography in this population-based, retrospective cohort study.

METHODS

Individuals diagnosed with CRC from 1992 to 2016 or who died of CRC from 1980 to 2018 in Canada were studied. Geography was determined using an individual's postal code at diagnosis from the Canadian Cancer Registry or province or territory of death from the Canadian Vital Statistics Death Database. Geography was categorized into Atlantic, Central, Prairies, West, and Territories. Canadian Cancer Registry data were used to determine CRC incidence from 1992 to 2016. Canadian Vital Statistics Death data were used to determine CRC mortality from 1980 to 2018.

RESULTS

Among all age groups, CRC incidence was highest in Atlantic Canada, was lowest in Western Canada, and increased with age. CRC incidence increased over time for individuals aged 20-44 years and was stable or decreased for other age groups in all regions. CRC mortality was highest in Atlantic Canada and lowest in the Prairies and Western Canada. CRC mortality decreased for individuals in all age groups and regions except among individuals aged 20-49 years in the Territories.

DISCUSSION

Most of Canada has not yet seen an increase in CRC burden in the age group of 45-49 years, which is a reason to not lower the start age for CRC screening in Canada. Targeted CRC screening should be considered for individuals younger than 50 years who live in the Territories.

Artificial Intelligence for Cancer Detection-A Bibliometric Analysis and Avenues for Future Research

After cardiovascular diseases, cancer is responsible for the most deaths worldwide. Detecting a cancer disease early improves the chances for healing significantly. One group of technologies that is increasingly applied for detecting cancer is artificial intelligence. Artificial intelligence has great potential to support clinicians and medical practitioners as it allows for the early detection of carcinomas. During recent years, research on artificial intelligence for cancer detection grew a lot. Within this article, we conducted a bibliometric study of the existing research dealing with the application of artificial intelligence in cancer detection. We analyzed 6450 articles on that topic that were published between 1986 and 2022. By doing so, we were able to give an overview of this research field, including its key topics, relevant outlets, institutions, and articles. Based on our findings, we developed a future research agenda that can help to advance research on artificial intelligence for cancer detection. In summary, our study is intended to serve as a platform and foundation for researchers that are interested in the potential of artificial intelligence for detecting cancer.

Systematic review of shared decision-making in guidelines about colorectal cancer screening

INTRODUCTION

We aimed to systematically evaluate quality of shared decision-making (SDM) in colorectal cancer (CRC) screening clinical practice guidelines (CPGs) and consensus statements (CSs).

METHODS

Search for CRC screening guidances was from 2010 to November 2021 in EMBASE, Web of Science, MEDLINE, Scopus and CDSR, and the World Wide Web. Three independent reviewers and an arbitrator rated the quality of each guidance using a SDM quality assessment tool (maximum score: 31). Reviewer agreement was 0.88.

RESULTS

SDM appeared in 41/83 (49.4%) CPGs and 9/19 (47.4%) CSs. None met all the quality criteria, and 51.0% (52/102) failed to meet any quality items. Overall compliance was low (mean 1.63, IQR 0-2). Quality was better in guidances published after 2015 (mean 1, IQR 0-3 vs. mean 0.5, IQR 0-1.5; p = 0.048) and when the term SDM was specifically reported (mean 4.5, IQR 2.5-4.5 vs. mean 0.5, IQR 0-1.5; p < 0.001). CPGs underpinned by systematic reviews showed better SDM quality than consensus (mean 1, IQR 0-3 vs. mean 0, IQR 0-2, p = 0.040).

CONCLUSION

SDM quality was suboptimal and mentioned in less than half of the guidances, and recommendations were scarce. Guideline developers should incorporate evidence-based SDM recommendations in guidances to underpin the translation of evidence into practice.

Adaptation of Clinical Practice Guideline for Colorectal Cancer Screening in People with Average Risk in Isfahan Province

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer among adults in Iran. The aim of colorectal cancer screening is to reduce the cancer burden in the population by diagnosing the disease in its early stages.

METHODS

We adapted this guideline for the moderate CRC risk population for Isfahan to determine how to screen them and when to start and end the CRC screening. This guideline was developed by clinical appraisal and review of the evidence, available clinical guidelines, and in consultation with members of the Isfahan Chamber of Iranian association of gastroenterology and hepatology.

RESULTS

In screening people with average risk for CRC who use personal resources and personally pay all the costs, colonoscopy is recommended as the first choice to be done every 10 years. In case of negative colonoscopy, we recommend FIT test to prevention of interval cancer every 5 years. In screening of people with average risk of CRC, FIT is suggested to be done every 2 years as a first-choice method test for those who use public resources and do not pay for this service personally. In screening individuals with average risk for CRC, g-FOBT is not recommended as the first method of choice. Repeating positive guaiac test is not recommended and if positive, colonoscopy is suggested.

Clinician based decision tool to guide recommended interval between colonoscopies: development and evaluation pilot study

Background

Optimal intervals between repeat colonoscopies could improve patient outcomes and reduce costs. We evaluated: (a) concordance between clinician and guideline recommended colonoscopy screening intervals in Winnipeg, Manitoba, (b) clinician opinions about the utility of an electronic decision-making tool to aid in recommending screening intervals, and (c) the initial use of a decision-making smartphone/web-based application.

Methods

Clinician endoscopists and primary care providers participated in four focus groups (N = 22). We asked participating clinicians to evaluate up to 12 hypothetical scenarios and compared their recommended screening interval to those of North American guidelines. Fisher’s exact tests were used to assess differences in agreement with guidelines. We developed a decision-making tool and evaluated it via a pilot study with 6 endoscopists.

Result

53% of clinicians made recommendations that agreed with guidelines in ≤ 50% of the hypothetical scenarios. Themes from focus groups included barriers to using a decision-making tool: extra time to use it, less confidence in the results of the tool over their own judgement, and having access to the information required by the tool (e.g., family history). Most were willing to try a tool if it was quick and easy to use. Endoscopists participating in the tool pilot study recommended screening intervals discordant with guidelines 35% of the time. When their recommendation differed from that of the tool, they usually endorsed their own over the guideline.

Conclusions

Endoscopists are overconfident and inconsistent with applying guidelines in their polyp surveillance interval recommendations. Use of a decision tool may improve knowledge and application of guidelines. A change in practice may require that the tool be coupled with continuing education about evidence for improved outcomes if guidelines are followed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-01872-z.

Predictors of CRC Stage at Diagnosis among Male and Female Adults Participating in a Prospective Cohort Study: Findings from Alberta's Tomorrow Project

Colorectal cancer (CRC) is a leading cause of morbidity and mortality in Canada. CRC screening and other factors associated with early-stage disease can improve CRC treatment efficacy and survival. This study examined factors associated with CRC stage at diagnosis among male and female adults using data from a large prospective cohort study in Alberta, Canada. Baseline data were obtained from healthy adults aged 35–69 years participating in Alberta’s Tomorrow Project. Factors associated with CRC stage at diagnosis were evaluated using Partial Proportional Odds models. Analyses were stratified to examine sex-specific associations. A total of 267 participants (128 males and 139 females) developed CRC over the study period. Among participants, 43.0% of males and 43.2% of females were diagnosed with late-stage CRC. Social support, having children, and caffeine intake were predictors of CRC stage at diagnosis among males, while family history of CRC, pregnancy, hysterectomy, menopausal hormone therapy, lifetime number of Pap tests, and household physical activity were predictive of CRC stage at diagnosis among females. These findings highlight the importance of sex differences in susceptibility to advanced CRC diagnosis and can help inform targets for cancer prevention programs to effectively reduce advanced CRC and thus improve survival.

New scoring systems for predicting advanced proximal neoplasia in asymptomatic adults with or without knowing distal colorectal findings: a prospective, cross-sectional study

BACKGROUND

Models estimating risk for advanced proximal colorectal neoplasia (APN) may be used to select colorectal cancer (CRC) screening test, either prior to knowing distal colorectal findings or afterward. Current models have only fair discrimination and nearly all require knowing distal findings.

OBJECTIVE

Derive and test risk prediction models for APN with and without distal findings.

SETTING

Selected endoscopy centers within central Indiana, USA.

PARTICIPANTS

Average-risk persons undergoing first-time screening colonoscopy.

INTERVENTIONS

Demographics, personal and family medical history, lifestyle factors and physical measures were linked to the most advanced finding in proximal and distal colorectal segments. For both models, logistic regression identified factors independently associated with APN on a derivation set. Based on equation coefficients, points were assigned to each factor, and risk for APN was examined for each score. Scores with comparable risks were collapsed into risk categories. Both models and their scoring systems were tested on the validation set.

MAIN OUTCOME

APN, defined as any adenoma or sessile serrated lesion ≥1 cm, one with villous histology or high-grade dysplasia, or CRC proximal to the descending colon.

RESULTS

Among 3025 subjects in the derivation set (mean age 57.3 ± 6.5 years; 52% women), APN prevalence was 4.5%; 2859 (94.5%) had complete data on risk factors. Independently associated with APN were age, sex, cigarette smoking, cohabitation status, metabolic syndrome, non-steroidal anti-inflammatory drug use and physical activity. This model (without distal findings) was well-calibrated (P = 0.62) and had good discrimination (c-statistic = 0.73). In low-, intermediate- and high-risk groups that comprised 21, 58 and 21% of the sample, respectively, APN risks were 1.47% (95% CI, 0.67-2.77%), 3.09% (CI, 2.31-4.04%) and 11.6% (CI, 9.10-14.4%), respectively (P < 0.0001), with no proximal CRCs in the low-risk group and 2 in the intermediate-risk group. When tested in the validation set of 1455, the model retained good metrics (calibration P = 0.85; c-statistic = 0.83), with APN risks in low- (22%), intermediate- (56%) and high-risk (22%) subgroups of 0.62% (CI, 0.08-2.23%) 2.20% (CI, 1.31-3.46%) and 13.0% (CI, 9.50-17.2%), respectively (P < 0.0001). There were no proximal CRCs in the low-risk group, and two in the intermediate-risk group. The model with distal findings performed comparably, with validation set metrics of 0.18 for calibration, 0.76 for discrimination and APN risk (% sample) in low-, intermediate-, and high-risk groups of 1.1 (69%), 8.3 (22%) and 22.3% (9%).

CONCLUSION

These models stratify large proportions of average-risk persons into clinically meaningful risk groups, and could improve screening efficiency, particularly for noncolonoscopy-based programs.

Canadian Colorectal Cancer Screening Guidelines: Do They Need an Update Given Changing Incidence and Global Practice Patterns?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and second leading cause of cancer death in Canada. Organized screening programs targeting Canadians aged 50 to 74 at average risk of developing the disease have contributed to decreased rates of CRC, improved patient outcomes and reduced healthcare costs. However, data shows that recent incidence reductions are unique to the screening-age population, while rates in people under-50 are on the rise. Similar incidence patterns in the United States prompted the American Cancer Society and U.S. Preventive Services Task Force to recommend screening begin at age 45 rather than 50. We conducted a review of screening practices in Canada, framing them in the context of similar global health systems as well as the evidence supporting the recent U.S. recommendations. Epidemiologic changes in Canada suggest earlier screening initiation in average-risk individuals may be reasonable, but the balance of costs to benefits remains unclear.

Impact of colorectal cancer screening participation in remote northern Canada: A retrospective cohort study

BACKGROUND

Screening provides earlier colorectal cancer (CRC) detection and improves outcomes. It remains poorly understood if these benefits are realized with screening guidelines in remote northern populations of Canada where CRC rates are nearly twice the national average and access to colonoscopy is limited.

AIM

To evaluate the participation and impact of CRC screening guidelines in a remote northern population.

METHODS

This retrospective cohort study included residents of the Northwest Territories, a northern region of Canada, age 50-74 who underwent CRC screening by a fecal immunohistochemical test (FIT) between January 1, 2014 to March 30, 2019. To assess impact, individuals with a screen-detected CRC were compared to clinically-detected CRC cases for stage and location of CRC between 2014-2016. To assess participation, we conducted subgroup analyses of FIT positive individuals exploring the relationships between signs and symptoms of CRC at the time of screening, wait-times for colonoscopy, and screening outcomes. Two sample Welch t-test was used for normally distributed continuous variables, Mann-Whitney-Wilcoxon Tests for data without normal distribution, and Chi-square goodness of fit test for categorical variables. A P value of < 0.05 was considered to be statistically significant.

RESULTS

6817 fecal tests were completed, meaning an annual average screening rate of 25.04%, 843 (12.37%) were positive, 629 individuals underwent a follow-up colonoscopy, of which, 24.48% had advanced neoplasia (AN), 5.41% had CRC. There were no significant differences in stage, pathology, or location between screen-detected cancers and clinically-detected cancers. In assessing participation and screening outcomes, we observed 49.51% of individuals referred for colonoscopy after FIT were ineligible for CRC screening, most often due to signs and symptoms of CRC. Individuals were more likely to have AN if they had signs and symptoms of cancer at the time of screening, waited over 180 d for colonoscopy, or were indigenous [respectively, estimated RR 1.18 95%CI of RR (0.89-1.59)]; RR 1.523 (CI: 1.035, 2.240); RR 1.722 (CI: 1.165, 2.547)].

CONCLUSION

Screening did not facilitate early cancer detection but facilitated higher than anticipated AN detection. Signs and symptoms of CRC at screening, and long colonoscopy wait-times appear contributory.

Time Trends in the Diagnosis of Colorectal Cancer With Obstruction, Perforation, and Emergency Admission After the Introduction of Population-Based Organized Screening

IMPORTANCE

Up to 30% of patients with a diagnosis of colorectal cancer (CRC) present as an emergency (an intestinal obstruction, perforation, or emergency hospital admission) (OPE). There are limited data about the association of organized, population-based colorectal cancer screening with the rate of emergency presentations.

OBJECTIVE

To examine the association of CRC screening with OPE at cancer diagnosis and time trends in the rate of OPE after the start of organized CRC screening using a highly sensitive fecal occult blood test.

DESIGN, SETTING, AND PARTICIPANTS

A historical cohort study was conducted among 1861 individuals 52 to 74 years of age with a diagnosis of CRC from January 1, 2007, to December 31, 2015, who lived in Winnipeg, Manitoba, a province with universal health care and an organized CRC screening program. Statistical analysis was performed from January 22, 2019, to February 26, 2020.

EXPOSURES

Variables included prior CRC screening, era of diagnosis, cancer stage at diagnosis, tumor site in the colon, area level mean household income, primary care continuity of care, and comorbidity.

MAIN OUTCOMES AND MEASURES

The primary outcomes were defined as an OPE. Logistic regression was used to evaluate factors associated with OPE at CRC diagnosis. Trends over time were calculated using Joinpoint Regression.

RESULTS

From 2007 to 2015, 1861 individuals 52 to 74 years of age (1133 men; median age, 65.1 years [interquartile range, 60.0-70.3 years]) received a diagnosis of CRC in Winnipeg. Most individuals had good continuity of care and moderate comorbidities. Overall, 345 individuals (18.5%) had an OPE. The rate of emergency hospital admissions decreased significantly from 2007 (the start of the organized, province-wide CRC screening program) to 2015 (annual change, -7.1%; 95% CI, -11.3% to -2.8%; P = .01). There was no change in the rate of obstructions or perforations or stage IV CRCs. Individuals who were up to date for CRC screening were significantly less likely to receive a diagnosis of an OPE (odds ratio, 0.38; 95% CI, 0.28-0.50; P < .001). The results were similar after adding emergency department visits and stage IV CRC at diagnosis to the outcome.

CONCLUSIONS AND RELEVANCE

This study suggests that the rate of emergency hospital admissions decreased over time for individuals who underwent CRC screening, but there was no change in the rate of obstructions and perforations. Individuals who were up to date for CRC screening were less likely to have a CRC diagnosis with an OPE.

Comparative effectiveness and cost-effectiveness analysis of a urine metabolomics test vs. alternative colorectal cancer screening strategies

PURPOSE

Despite the success of provincial screening programs, colorectal cancer (CRC) is still the third most common cancer in Canada and the second most common cause of cancer-related death. Fecal-based tests, such as fecal occult blood test (FOBT) and fecal immunochemical test (FIT), form the foundation of the provincial CRC screening programs in Canada. However, those tests have low sensitivity for CRC precursors, adenomatous polyps and have low adherence. This study evaluated the effectiveness and cost-effectiveness of a new urine metabolomic-based test (UMT) that detects adenomatous polyps and CRC.

METHODS

A Markov model was designed using data from the literature and provincial healthcare databases for Canadian at average risk for CRC; calibration was performed against statistics data. Screening strategies included the following: FOBT every year, FIT every year, colonoscopy every 10 years, and UMT every year. The costs, quality adjusted life years (QALY) gained, and incremental cost-effectiveness ratios (ICERs) for each strategy were estimated and compared.

RESULTS

Compared with no screening, a UMT strategy reduced CRC mortality by 49.9% and gained 0.15 life years per person at $42,325/life year gained in the base case analysis. FOBT reduced CRC mortality by 14.9% and gained 0.04 life years per person at $25,011/life year gained. FIT reduced CRC mortality by 35.8% and gained 0.11 life years per person at $25,500/life year while colonoscopy reduced CRC mortality by 24.7% and gained 0.08 life years per person at $50,875/life year.

CONCLUSIONS

A UMT strategy might be a cost-effective strategy when used in programmatic CRC screening programs.

Clinical Practice Guideline on Screening for Colorectal Cancer in Individuals With a Family History of Nonhereditary Colorectal Cancer or Adenoma: The Canadian Association of Gastroenterology Banff Consensus

BACKGROUND & AIMS

A family history (FH) of colorectal cancer (CRC) increases the risk of developing CRC. These consensus recommendations developed by the Canadian Association of Gastroenterology and endorsed by the American Gastroenterological Association, aim to provide guidance on screening these high-risk individuals.

METHODS

Multiple parallel systematic review streams, informed by 10 literature searches, assembled evidence on 5 principal questions around the effect of an FH of CRC or adenomas on the risk of CRC, the age to initiate screening, and the optimal tests and testing intervals. The GRADE (Grading of Recommendation Assessment, Development and Evaluation) approach was used to develop the recommendations.

RESULTS

Based on the evidence, the Consensus Group was able to strongly recommend CRC screening for all individuals with an FH of CRC or documented adenoma. However, because most of the evidence was very-low quality, the majority of the remaining statements were conditional ("we suggest"). Colonoscopy is suggested (recommended in individuals with ≥2 first-degree relatives [FDRs]), with fecal immunochemical test as an alternative. The elevated risk associated with an FH of ≥1 FDRs with CRC or documented advanced adenoma suggests initiating screening at a younger age (eg, 40-50 years or 10 years younger than age of diagnosis of FDR). In addition, a shorter interval of every 5 years between screening tests was suggested for individuals with ≥2 FDRs, and every 5-10 years for those with FH of 1 FDR with CRC or documented advanced adenoma compared to average-risk individuals. Choosing screening parameters for an individual patient should consider the age of the affected FDR and local resources. It is suggested that individuals with an FH of ≥1 second-degree relatives only, or of nonadvanced adenoma or polyp of unknown histology, be screened according to average-risk guidelines.

CONCLUSIONS

The increased risk of CRC associated with an FH of CRC or advanced adenoma warrants more intense screening for CRC. Well-designed prospective studies are needed in order to make definitive evidence-based recommendations about the age to commence screening and appropriate interval between screening tests.

FECAL OCCULT BLOOD: A COMPARISON OF CHEMICAL AND IMMUNOCHEMICAL TESTS

BACKGROUND

Colorectal bleeding is a warning sign that may be identified by fecal occult blood testing. A positive fecal occult blood test result requires a subsequent colonoscopy, a costly and invasive examination. Therefore, the use of diagnostic tests with optimal sensitivity and specificity is warranted. In this study, we evaluated four different fecal occult blood tests in 176 patients undergoing colonoscopy and compared their results.

OBJECTIVE

To assess the sensitivity, specificity and predictive values of chemical and immunochemical fecal occult blood tests in patients undergoing colonoscopy and to evaluate the degree of concordance between the tests and colonoscopy.

METHODS

Patients with indications for colonoscopy also underwent fecal occult blood testing by chemical (toluidine test) and immunochemical methods, employing three commercially available kits. Based on the endoscopic findings, the colonoscopy was rated as positive or negative for colorectal bleeding. The degree of concordance between the fecal occult blood tests and the colonoscopy was evaluated by the kappa index.

RESULTS

Forty-four (25%) colonoscopies were categorized as positive for colorectal bleeding. The toluidine test presented lower concordance than the immunochemical tests, which showed moderate concordance with the colonoscopy. The toluidine test had the least sensitivity, specificity, and positive and negative predictive values.

CONCLUSION

The immunochemical fecal occult blood tests showed greater sensitivity, specificity and predictive values in detecting colorectal bleeding. The immunochemical tests had superior indexes of agreement with colonoscopy compared to the toluidine test.

Interval colorectal cancer rates after Hemoccult Sensa and survival by detection mode for individuals diagnosed with colorectal cancer in Winnipeg, Manitoba

Objective

To assess the performance of the Sensa fecal occult blood test (FOBT) in a population-based screening program.

Setting

Manitoba, Canada.

Methods

This historical cohort study included individuals 52 to 74 years of age diagnosed with colorectal cancer (CRC) from 2008 to 2013. CRCs were categorized by detection following a screening program FOBT (Sensa), non-program FOBT (non-Sensa), or no FOBT. Screening program CRCs were classified as program-detected, interval program, or non-compliant. Logistic regression was used to compare characteristics by detection mode. Cox regression adjusted for lead-time was used to examine the effect of detection mode on survival.

Results

1,498 individuals were diagnosed with CRC; 132 (8.8%) had a screening program FOBT, 626 (41.8%) had a non-program FOBT, and 740 (49.4%) had no FOBT. Of the screening program FOBT CRCs, 72 were program-detected (54.5%), 42 were interval program (31.8%), and 18 were non-compliant (13.6%). Sensa interval cancer rate was 37.4% and sensitivity was 63.1% (95% Confidence Interval (CI): 54.3%-72.0%). The risk of death for individuals that had a non-program (Hazard ratio (HR) = 0.57, 95% CI:0.44–0.75) or a screening program FOBT (HR = 0.55, 95% CI:0.31–0.97) was lower than no FOBT. There was no significant difference in the risk of death for interval, non-compliant, and non-program CRCs compared to program-detected CRCs. Adjusting for lead time bias, sex, income quintile, tumour location, and age at diagnosis did not appreciably change the risk estimates.

Conclusion

More than one-third of CRCs may not be detected by Sensa. There may be no difference in survival between CRC detected by Sensa and non-Sensa FOBTs.

Predictors of non-adherence to colorectal cancer screening among immigrants to Ontario, Canada: a population-based study

Though colorectal cancer (CRC) screening rates have increased over time in Ontario, Canada, immigrants continue to have lower rates of screening. This study examines the association between non-adherence to CRC screening and immigration, socio-demographic, healthcare utilization, and primary care physician characteristics among immigrants to Ontario. This is a population-based retrospective cross-sectional study that uses healthcare administrative databases housed at the Institute for Clinical Evaluative Sciences. Our cohort comprised immigrants aged 60 to 74 years who lived in Ontario on March 31, 2015 and who had been eligible for the Ontario Health Insurance Plan for at least 10 years. The outcome was lack of adherence to CRC screening with any modality (fecal occult blood test, flexible sigmoidoscopy, colonoscopy) on March 31, 2015. Our cohort contained 182,949 immigrants. Overall 70,134 (38%) individuals were not adherent to screening. Risk of non-adherence to CRC screening was higher among immigrants who were from low (adjusted relative risk [ARR] 1.35, 95%CI 1.28-1.42) or low-middle (ARR 1.27, 95%CI 1.24-1.30, population-attributable risk [PAR] 9.8%) income countries and refugees (ARR 1.09, 95%CI 1.06-1.11). Compared to those from the United States, Australia, and New Zealand, immigrants from most other world regions, particularly Eastern Europe and Central Asia (ARR 1.28, 95%CI 1.21-1.37), had higher risks of non-adherence. Non-immigration factors such as low healthcare use and lack of primary care enrolment also increased the risk of non-adherence to screening. These findings can be used to inform future efforts to improve uptake of CRC screening among immigrant groups.

Characteristics of Patients with Colonic Polyps Requiring Segmental Resection

BACKGROUND

It is unclear if the availability of new techniques for removal of large colonic polyps has affected the use of segmental colon resection. We sought to evaluate the characteristics of polyps undergoing surgical resection, including involvement of therapeutic gastroenterologists (TG).

METHODS

484 patients had a colonic resection; 165 (34%) were identified from the pathology database with polyp, adenoma, or mass in the clinical history field; these charts were reviewed.

RESULTS

128 patients (mean age 68 yrs, 72% male) were included. The mean polyp size was 2.9 cm (0.4 cm-12.0 cm). Adenocarcinoma was diagnosed in 50 (39.1%). 97 (75.8%) patients had a polyp that was felt to be unresectable by EMR, and 31 (24.2%) underwent successful EMR followed by surgery for adenocarcinoma (n = 29). The indication for surgery in those with unresectable polyps was variable and was not clearly documented in 51 (52.6%); only 17 of these patients (17.5%) had a TG involved.

CONCLUSION

A high proportion of polyps managed by segmental resection did not contain adenocarcinoma. This data suggests that even in a tertiary care center where advanced endoscopic techniques are easily available, they are not always utilized. Educational endeavors to ensure that ideal pathways of intervention are utilized require implementation.

Current standards and new developments of colorectal polyp management and resection techniques

Colonoscopy and endoscopic removal of precancerous polyps play an important role in colorectal cancer (CRC) prevention. Improved endoscopes and quality standards have led to an increasing polyp and adenoma detection rate. Optimal polyp resection techniques and management strategies are key for an effective colonoscopy practice. Areas covered: Strategies for how to improve diminutive polyp (polyps up to 5 mm in size) management are discussed because of their high prevalence. Systematic removal of diminutive polyps leads to increasing costs of colonoscopy practice, while the effect on colorectal cancer prevention might be negligible. Furthermore, polypectomy recommendations for mid-size and large polyps are provided. For all larger polyps larger, complete and safe resection is mandatory to avoid post colonoscopy cancers. The focus for managing such larger polyps is to use new techniques (i.e. cold snares) and to attempt complete removal and to reduce post-polypectomy complications. Expert commentary: The resect-and-discard strategy is a promising management strategy for diminutive polyps. However, modification of this approach might be required in order to make widespread adoption feasible. Cold snare polypectomy is a promising new approach for small polyp resection. For resection of large polyps adequate treatment recommendations with regard to endoscopic mucosal resection and complication prevention are provided.

The Association between Distal Findings and Proximal Colorectal Neoplasia: A Systematic Review and Meta-Analysis

OBJECTIVES

Whether screening participants with distal hyperplastic polyps (HPs) detected by flexible sigmoidoscopy (FS) should be followed by subsequent colonoscopy is controversial. We evaluated the association between distal HPs and proximal neoplasia (PN)/advanced proximal neoplasia (APN) in asymptomatic, average-risk patients.

METHODS

We searched Ovid Medline, EMBASE, and the Cochrane Library from inception to 30 June 2016 and included all screening studies that examined the relationship between different distal findings and PN/APN. Data were independently extracted by two reviewers with disagreements resolved by a third reviewer. We pooled absolute risks and odds ratios (ORs) with a random effects meta-analysis. Seven subgroup analyses were performed according to study characteristics. Heterogeneity was characterized with the I² statistics.

RESULTS

We analyzed 28 studies (104,961 subjects). When compared with normal distal findings, distal HP was not associated with PN (OR=1.16, 95% confidence interval (CI)=0.89-1.51, P=0.14, I²=40%) or APN (OR=1.09, 95% CI=0.87-1.36, P=0.39, I²=5%), while subjects with distal non-advanced or advanced adenoma had higher odds of PN/APN. Higher odds of PN/APN were observed for more severe distal lesions. Weaker association between distal and proximal findings was noticed in studies with higher quality, larger sample size, population-based design, and more stringent endoscopy quality-control measures. The Egger's regression tests showed all P>0.05.

CONCLUSIONS

Distal HP is not associated with PN/APN in asymptomatic screening population when compared with normal distal findings. Hence, the presence of distal HP alone detected by FS does not automatically indicate colonoscopy referral for all screening participants, as other risk factors of PN/APN should be considered.

Practical considerations for large-scale gut microbiome studies

First insights on the human gut microbiome have been gained from medium-sized, cross-sectional studies. However, given the modest portion of explained variance of currently identified covariates and the small effect size of gut microbiota modulation strategies, upscaling seems essential for further discovery and characterisation of the multiple influencing factors and their relative contribution. In order to guide future research projects and standardisation efforts, we here review currently applied collection and preservation methods for gut microbiome research. We discuss aspects such as sample quality, applicable omics techniques, user experience and time and cost efficiency. In addition, we evaluate the protocols of a large-scale microbiome cohort initiative, the Flemish Gut Flora Project, to give an idea of perspectives, and pitfalls of large-scale faecal sampling studies. Although cryopreservation can be regarded as the gold standard, freezing protocols generally require more resources due to cold chain management. However, here we show that much can be gained from an optimised transport chain and sample aliquoting before freezing. Other protocols can be useful as long as they preserve the microbial signature of a sample such that relevant conclusions can be drawn regarding the research question, and the obtained data are stable and reproducible over time.

Development and Validation of a High-Throughput Mass Spectrometry Based Urine Metabolomic Test for the Detection of Colonic Adenomatous Polyps

Background: Colorectal cancer is one of the leading causes of cancer deaths worldwide. The detection and removal of the precursors to colorectal cancer, adenomatous polyps, is the key for screening. The aim of this study was to develop a clinically scalable (high throughput, low cost, and high sensitivity) mass spectrometry (MS)-based urine metabolomic test for the detection of adenomatous polyps. Methods: Prospective urine and stool samples were collected from 685 participants enrolled in a colorectal cancer screening program to undergo colonoscopy examination. Statistical analysis was performed on 69 urine metabolites measured by one-dimensional nuclear magnetic resonance spectroscopy to identify key metabolites. A targeted MS assay was then developed to quantify the key metabolites in urine. A MS-based urine metabolomic diagnostic test for adenomatous polyps was established using 67% samples (un-blinded training set) and validated using the remaining 33% samples (blinded testing set). Results: The MS-based urine metabolomic test identifies patients with colonic adenomatous polyps with an AUC of 0.692, outperforming the NMR based predictor with an AUC of 0.670. Conclusion: Here we describe a clinically scalable MS-based urine metabolomic test that identifies patients with adenomatous polyps at a higher level of sensitivity (86%) over current fecal-based tests (<18%).

Clinical validation of a novel urine-based metabolomic test for the detection of colonic polyps on Chinese population

PURPOSE

Colorectal cancer is the fifth leading cause of cancer-related deaths in China. When detected early, with the removal of adenomatous polyps, precursors of colorectal cancer, it is preventable. The aim of this study was to evaluate a novel urine-based metabolomic diagnostic test for the detection of adenomatous polyps, PolypDx™, that was originally developed and validated using 1000 samples from Canadian Cohort, on Chinese population.

METHODS

Prospective urine samples were collected from 1000 participants undergoing colonoscopy examination, from March 2013 to July 2014 at Minhang District, Shanghai Centre for Disease Control and Prevention. One-dimensional nuclear magnetic resonance spectra of urine metabolites were analyzed to determine the concentrations of three key metabolites used in PolypDx™. The predicted results were then compared to the gold standard for colorectal cancer diagnostic, colonoscopy. Area under curve (AUC) was calculated specifically for the Chinese population and compared with the Canadian dataset. Sensitivity and specificity of this urine-based metabolomic diagnostic test were also compared with three commercially available fecal-based tests.

RESULTS

An AUC of 0.717 for PolypDx™ was calculated on Chinese dataset which is slightly lower than the AUC on the Canadian dataset. A sensitivity of 82.6% and a specificity of 42.4% were achieved on Chinese dataset.

CONCLUSIONS

Here, we validated a novel urine-based metabolomic diagnostic test for the detection of adenomatous polyps, PolypDx™, on Chinese population through a sample size of 1000 participants with a greater level of sensitivity than fecal-based tests.

Assessing family history of chronic disease in primary care: Prevalence, documentation, and appropriate screening

OBJECTIVE

To assess the proportion of primary care patients who report a family history (FH) of type 2 diabetes, coronary artery disease, breast cancer, or colorectal cancer (CRC); assess concordance of FH information derived from the electronic medical record (EMR) compared with patient-completed health questionnaires; and assess whether appropriate screening was informed by risk based solely on FH.

DESIGN

Data from the BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) trial were used. Patients were mailed questionnaires. Baseline FH and screening data were obtained for enrolled patients from the EMR and health questionnaires.

SETTING

Ontario and Alberta.

PARTICIPANTS

Randomly selected patients from 8 family practices.

MAIN OUTCOME MEASURES

Agreement on FH between the EMR and questionnaire was determined; logistic regression was used to assess significant predictors of screening.

RESULTS

In total, 775 of 789 (98%) patients completed the health questionnaire. The mean age of participants was 52.5 years and 72% were female. A minimum of 12% of patients (range 12% to 36%) had a reported FH of 1 of 4 chronic diseases. Among patients with positive FH, the following proportions of patients had that FH recorded in the EMR compared with the questionnaire: diabetes, 24% in the EMR versus 36% on the questionnaire, κ = 0.466; coronary artery disease, 35% in the EMR versus 22% on the questionnaire, κ = 0.225; breast cancer, 21% in the EMR versus 22% on the questionnaire, κ = 0.241; and CRC, 12% in the EMR versus 14% on the questionnaire, κ = 0.510. There was moderate agreement for diabetes and CRC. The presence of FH was a significant predictor of CRC screening (odds ratio 1.9, 95% CI 1.1 to 3.1).

CONCLUSION

A moderate prevalence of FH was found for 4 conditions for which screening recommendations vary with risk based on FH. Having patients self-complete an FH was thought to be feasible; however, questions about FH accuracy and completeness from both self-report and EMR remain. Work is needed to determine how to facilitate the adoption of FH tools into practice as well as strategies linking familial risk to appropriate screening.Trial registration number ISRCTN07170460 (ISRCTN Registry).

Policy of screening for colorectal cancer in Saudi Arabia: A prospective analysis

Colorectal cancer (CRC) is one of the most common cancers worldwide. Several policies of CRC screening are available in different countries. The idea of screening is to identify patients at risk by detection of precancerous and small cancers early enough before they become advanced. In Saudi Arabia (SA), there is no countrywide policy for CRC screening despite the increasing incidence of the disease. Screening for CRC is a multidisciplinary approach that requires education programs, substantial financial support, several logistic measures, and predetermined resources before implementing such a program. We performed a prospective and systematic analysis of the of the screening policy of CRC in SA in view of high demand, anticipated development, and implementation of such a policy in the near future. We also attempted to investigate the justification for developing such a policy, as well as the difficulties, barriers, and opportunities that may be faced in its implementation. Further, we highlighted the current view of similar international screening policies. In this analysis, we adopted the framework for health policy analysis that examines four areas which may affect policy development, namely; content, context, process and actors.

Colorectal cancer screening: Opportunities to improve uptake, outcomes, and disparities

Colorectal cancer screening has become a standard of care in industrialized nations for those 50 to 75 years of age, along with selected high-risk populations. While colorectal cancer screening has been shown to reduce both the incidence and mortality of colorectal cancer, it is a complex multi-disciplinary process with a number of important steps that require optimization before tangible improvements in outcomes are possible. For both opportunistic and programmatic colorectal cancer screening, poor participant uptake remains an ongoing concern. Furthermore, current screening modalities (such as the guaiac based fecal occult blood test, fecal immunochemical test and colonoscopy) may be used or performed suboptimally, which can lead to missed neoplastic lesions and unnecessary endoscopic evaluations. The latter poses the risk of adverse events, such as perforation and post-polypectomy bleeding, as well as financial impacts to the healthcare system. Moreover, ongoing disparities in colorectal cancer screening persist among marginalized populations, including specific ethnic minorities (African Americans, Hispanics, Asians, Indigenous groups), immigrants, and those who are economically disenfranchised. Given this context, we aimed to review the current literature on these important areas pertaining to colorectal cancer screening, particularly focusing on the guaiac based fecal occult blood test, the fecal immunochemical test and colonoscopy.

Designing clinical and genetic guidelines of colorectal cancer screening as an effective roadmap for risk management

AIM

We aimed to present clinical and genetic guidelines of colorectal cancer screening for risk assessment of populations at risk.

BACKGROUND

National guidelines can be used as a guide for choosing the method of screening for each individual. These guidelines facilitate decision making and support the delivery of cancer screening service.

METHODS

In the first step, a comparative study was performed by using secondary data extracted from the literature review. Three countries (Canada, Australia and United States) were selected from 25 countries that are member in the International Cancer Screening Network (ICSN). The second step of study was qualitative survey. The study was based on the grounded theory approach. Study tool was semi-structured interview. Interviewing involves asking questions and getting answers from participants. 22 expert's perspectives about guidelines of colorectal cancer screening were surveyed.

RESULTS

Screening program of selected countries was compared. Countries were surveyed by number of risk groups and subgroups, criteria for risk assessment, beginning age, recommendations, screening approaches and intervals. Australia and United States have three risk groups and Canada has two risk groups. Four risk groups were defined in the national guideline, including high risk, increased risk, average and low risk group. The high risk group comprises of 8 subgroups, increased risk group comprises of 3 subgroups and average risk group contain 4 subgroups. Approved clinical criteria for hereditary syndromes and the roadmap of genetic and pathologic survey were designed.

CONCLUSIONS

Guidelines and pathways have a vital role in the quality improvement of CRC screening program. National guidelines were refined according to the environmental and genetic criteria of colorectal cancer in Iran. These guidelines provide evidence-based recommendations by risk groups. National pathways as a risk assessment tool can evaluate and improve the processes and outcomes of cancer screening in practice. One of the suggestions for future research is the designing expert system for real-time decision making during a clinical interaction.

Fecal Immunochemical Test (FIT) for Colon Cancer Screening: Variable Performance with Ambient Temperature

INTRODUCTION

Fecal immunochemical tests (FITs) are widely used in colorectal cancer (CRC) screening, but hemoglobin degradation, due to exposure of the collected sample to high temperatures, could reduce test sensitivity. We examined the relation of ambient temperature exposure with FIT positivity rate and sensitivity.

METHODS

This was a retrospective cohort study of patients 50 to 75 years in Kaiser Permanente Northern California's CRC screening program, which began mailing FIT kits annually to screen-eligible members in 2007. Primary outcomes were FIT positivity rate and sensitivity to detect CRC. Predictors were month, season, and daily ambient temperatures of test result dates based on US National Oceanic and Atmospheric Administration data.

RESULTS

Patients (n = 472,542) completed 1,141,162 FITs. Weekly test positivity rate ranged from 2.6% to 8.0% (median, 4.4%) and varied significantly by month (June/July vs December/January rate ratio [RR] = 0.79, 95% confidence interval [CI], 0.76 to 0.83) and season. FIT sensitivity was lower in June/July (74.5%; 95% CI, 72.5 to 76.6) than January/December (78.9%; 95% CI, 77.0 to 80.7).

CONCLUSIONS

FITs completed during high ambient temperatures had lower positivity rates and lower sensitivity. Changing kit design, specimen transportation practices, or avoiding periods of high ambient temperatures may help optimize FIT performance, but may also increase testing complexity and reduce patient adherence, requiring careful study.

Understanding the Effects of Competition for Constrained Colonoscopy Services with the Introduction of Population-level Colorectal Cancer Screening

BACKGROUND

Median wait times for gastroenterology services in Canada exceed consensus-recommended targets and have worsened substantially over the past decade. Meanwhile, efforts to control colorectal cancer have shifted their focus to screening asymptomatic, average-risk individuals. Along with increasing prevalence of colorectal cancer due to an aging population, screening programs are expected to add substantially to the existing burden on colonoscopy services, and create competition for limited services among individuals of varying risk. Failure to understand the effects of operational programmatic screening decisions may cause unintended harm to both screening participants and higher-risk patients, make inefficient use of limited health care resources, and ultimately hinder a program's success.

METHODS

We present a new simulation model (Simulation of Cancer Outcomes for Planning Exercises, or SCOPE) for colorectal cancer screening which, unlike many other colorectal cancer screening models, reflects the effects of competition for limited colonoscopy services between patient groups and can be used to guide planning to ensure adequate resource allocation. We include verification and validation results for the SCOPE model.

RESULTS

A discrete event simulation model was developed based on an epidemiological representation of colorectal cancer in a sample population. Colonoscopy service and screening modules were added to allow observation of screening scenarios and resource considerations. The model reproduces population-based data on prevalence of colorectal cancer by stage, and mortality by cause of death, age, and sex, and attendant demand and wait times for colonoscopy services.

CONCLUSIONS

The study model differs from existing screening models in that it explicitly considers the colonoscopy resource implications of screening activities and the impact of constrained resources on screening effectiveness.

Adult health checkup: Update on the Preventive Care Checklist Form©

OBJECTIVE

To describe updates to the Preventive Care Checklist Form© to help family physicians stay up to date with current preventive health care recommendations.

QUALITY OF EVIDENCE

The Ovid MEDLINE database was searched using specified key words and other terms relevant to the periodic health examination. Secondary sources, such as the Canadian Task Force on Preventive Health Care, the Public Health Agency of Canada, the Trip database, and the Canadian Medical Association Infobase, were also searched. Recommendations for preventive health care for average-risk adults were reviewed. Strong and weak recommendations are presented on the form in bold and italic text, respectively.

MAIN MESSAGE

Updates were made to the form based on the Canadian Task Force on Preventive Health Care recommendations on screening for obesity (2015), cervical cancer (2013), depression (2013), osteoporosis (2013), hypertension (2012), diabetes (2012, 2013), and breast cancer (2011). Updates were made based on recommendations from other Canadian organizations on screening for HIV (2013), screening for sexually transmitted infections (2013), immunizations (2012 to 2014), screening for dyslipidemia (2012), fertility counseling for women (2011, 2012), and screening for colorectal cancer (2010). Some previous recommendations were removed and others lacking evidence were not included.

CONCLUSION

The Preventive Care Checklist Form has been updated with current recommendations to enable family physicians to provide comprehensive, evidence-based care to patients during periodic health examinations.

More Is Not Always Better: A Randomized Trial Of Low Volume Oral Laxative, Enemas, And Combination Of Both Demonstrate That Enemas Alone Are Most Efficacious For Preparation For Flexible Sigmoidoscopy

OBJECTIVES

Colon cleansing for flexible sigmoidoscopy using a standard fleet enema does not provide adequate cleansing in a significant number of patients. We tested whether the addition of a low-volume oral cleansing agent could mitigate this challenge without significantly compromising patient tolerance.

HYPOTHESIS

Oral picosulfate with magnesium citrate (P/MC) would enhance the colon cleansing of patients undergoing sigmoidoscopy, as assessed by the modified Ottawa Bowel Preparation Score.

METHODS

A randomized single blinded trial comparing (1) a single dose (i.e., one sachet) of oral sodium picosulfate plus magnesium citrate (P/MC) administered the night before, (2) a single dose oral P/MC the night before plus sodium phosphate enema 1 h before leaving home, and (3) sodium phosphate enema alone 1 h before leaving home for flexible sigmoidoscopy was conducted on outpatients referred for sigmoidoscopy for symptom assessment.

RESULTS

A total 120 patients were randomized to the study groups. The main indication for sigmoidoscopy was investigation of rectal bleeding (n=80). There was no significant difference in bowel cleansing quality, measured by the endoscopist blinded to preparation, between P/MC, P/MC plus enema, and enema alone as measured by the modified Ottawa Bowel Preparation Scale (P=0.34) or the Aronchick Scale (P=0.13). Both oral P/MC regimens were associated with higher incidence of nausea, abdominal pain, bloating, and interrupted sleep than enema alone (P<0.05).

CONCLUSIONS

A single dose of oral P/MC administered the night before did not result in better colon cleansing for sigmoidoscopy when used alone or with an enema and was associated with more side effects (NCT 01554111).

Colorectal Cancer Screening

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. It is a potentially preventable disease and ideally suited to a screening program. CRC screening is an early detection strategy for occupational health nurses to offer in the workplace. Education and outreach are key components of this intervention. Many test options are available for CRC screening. This article is an integrative literature review that summarizes evidence to support colorectal screening in the workplace, offers screening recommendations from authoritative agencies, and provides guidance for occupational health nurses who plan to implement a screening program. Current screening limitations using fecal occult blood tests are addressed and an inventory of CRC screening activities in select countries is included.

Split-dose sodium picosulfate-magnesium citrate colonoscopy preparation achieves lower residual gastric volume with higher cleansing effectiveness than a previous-day regimen

BACKGROUND AND AIMS

It is known that sodium picosulfate-magnesium citrate (SPMC) bowel preparations are effective, well tolerated and safe, and that split-dosing is more effective for colon cleansing than previous-day regimens. Anesthetic guidelines consider that residual gastric fluid is independent of clear liquid fasting times. However, reluctance to use split-dosing persists. This may be due to limited data on residual gastric fluid volumes (RGFVs) and split-dosing bowel preparations, and that these may not be perceived as standard clear liquids. Furthermore, no studies are available on RGFV/residual gastric fluid pH (RGFpH) and SPMC. We aimed to evaluate the cleansing effectiveness and the RGFV/RGFpH achieved after an SPMC split-dosing regimen compared with a SPMC previous-day regimen.

METHODS

This was a single-center observational study. A total of 328 outpatients scheduled for simultaneous EGD and colonoscopy and following a split-dosing or previous-day regimen of SPMC were included. We prospectively measured colon cleanliness by using the Ottawa Bowel Preparation Scale, RGFV, and RGFpH.

RESULTS

Ottawa Bowel Preparation Scale scores for overall, right, mid-colon, and colon fluid were significantly better in the split-dosing group. In the split-dosing group, the 3- to 4-hour fasting time consistently achieved the best cleansing quality. RGFV was significantly lower in the split-dosing group (11.09 vs 18.62, P < .001). No significant differences in RGFpH were detected.

CONCLUSIONS

Split-dosing SPMC provides higher colon cleansing quality with lower RGFVs than previous-day SPMC regimens. SPMC in split-dosing acts exactly as a standard clear liquid acts, and thus anesthetic guidelines on this issue may be applied with no concerns.

Update on age-appropriate preventive measures and screening for Canadian primary care providers

OBJECTIVE

To summarize the best available age-appropriate, evidence-based guidelines for prevention and screening in Canadian adults.

QUALITY OF EVIDENCE

The Canadian Task Force on Preventive Health Care recommendations are the primary source of information, supplemented by relevant US Preventive Services Task Force recommendations when a Canadian task force guideline was unavailable or outdated. Leading national disease-specific or specialty-specific organizations' guidelines were also reviewed to ensure the most up-to-date evidence was included.

MAIN MESSAGE

Recommended screening maneuvers by age and sex are presented in a summary table highlighting the quality of evidence supporting these recommendations. An example of a template for use with electronic medical records or paper-based charts is presented.

CONCLUSION

Whether primary care providers use a dedicated preventive health visit or opportunistic preventive counseling and screening in their patient encounters, this summary of evidence-based recommendations can help maximize efficiency and prevent important omissions and unnecessary screening.

Correlating Quantitative Fecal Immunochemical Test Results with Neoplastic Findings on Colonoscopy in a Population-Based Colorectal Cancer Screening Program: A Prospective Study

Background and Aims. The Canadian Partnership Against Cancer (CPAC) recommends a fecal immunochemical test- (FIT-) positive predictive value (PPV) for all adenomas of ≥50%. We sought to assess FIT performance among average-risk participants of the British Columbia Colon Screening Program (BCCSP). Methods. From Nov-2013 to Dec-2014 consecutive participants of the BCCSP were assessed. Data was obtained from a prospectively collected database. A single quantitative FIT (NS-Plus, Alfresa Pharma Corporation, Japan) with a cut-off of ≥10 μg/g (≥50 ng/mL) was used. Results. 20,322 FIT-positive participants underwent CSPY. At a FIT cut-off of ≥10 μg/g (≥50 ng/mL) the PPV for all adenomas was 52.0%. Increasing the FIT cut-off to ≥20 μg/g (≥100 ng/mL) would increase the PPV for colorectal cancer (CRC) by 1.5% and for high-risk adenomas (HRAs) by 6.5% at a cost of missing 13.6% of CRCs and 32.4% of HRAs. Conclusions. As the NS-Plus FIT cut-off rises, the PPV for CRC and HRAs increases but at the cost of missed lesions. A cut-off of ≥10 μg/g (≥50 ng/mL) produces a PPV for all adenomas exceeding national recommendations. Health authorities need to take into consideration endoscopic resources when selecting a FIT positivity threshold.

Adherence to Competing Strategies for Colorectal Cancer Screening Over 3 Years

OBJECTIVES

We have shown that, in a randomized trial comparing adherence to different colorectal cancer (CRC) screening strategies, participants assigned to either fecal occult blood testing (FOBT) or given a choice between FOBT and colonoscopy had significantly higher adherence than those assigned to colonoscopy during the first year. However, how adherence to screening changes over time is unknown.

METHODS

In this trial, 997 participants were cluster randomized to one of the three screening strategies: (i) FOBT, (ii) colonoscopy, or (iii) a choice between FOBT and colonoscopy. Research assistants helped participants to complete testing only in the first year. Adherence to screening was defined as completion of three FOBT cards in each of 3 years after enrollment or completion of colonoscopy within the first year of enrollment. The primary outcome was adherence to assigned strategy over 3 years. Additional outcomes included identification of sociodemographic factors associated with adherence.

RESULTS

Participants assigned to annual FOBT completed screening at a significantly lower rate over 3 years (14%) than those assigned to colonoscopy (38%, P<0.001) or choice (42%, P<0.001); however, completion of any screening test fell precipitously, indicating the strong effect of patient navigation. In multivariable logistic regression analysis, being randomized to the choice or colonoscopy group, Chinese language, homosexuality, being married/partnered, and having a non-nurse practitioner primary care provider were independently associated with greater adherence to screening (P<0.01).

CONCLUSIONS

In a 3-year follow-up of a randomized trial comparing competing CRC screening strategies, participants offered a choice between FOBT and colonoscopy continued to have relatively high adherence, whereas adherence in the FOBT group fell significantly below that of the choice and colonoscopy groups. Patient navigation is crucial to achieving adherence to CRC screening, and FOBT is especially vulnerable because of the need for annual testing.

Pilot Validation Study: Canadian Global Rating Scale for Colonoscopy Services

Background. The United Kingdom Global Rating Scale (GRS-UK) measures unit-level quality metrics processes in digestive endoscopy. We evaluated the psychometric properties of its Canadian version (GRS-C), endorsed by the Canadian Association of Gastroenterology (CAG). Methods. Prospective data collection at three Canadian endoscopy units assessed GRS-C validity, reliability, and responsiveness to change according to responses provided by physicians, endoscopy nurses, and administrative personnel. These responses were compared to national CAG endoscopic quality guidelines and GRS-UK statements. Results. Most respondents identified the overarching theme each GRS-C item targeted, confirming face validity. Content validity was suggested as 18 out of 23 key CAG endoscopic quality indicators (78%, 95% CI: 56-93%) were addressed in the GRS-C; statements not included pertained to educational programs and competency monitoring. Concordance ranged 75-100% comparing GRS-C and GRS-UK ratings. Test-retest reliability Kappa scores ranged 0.60-0.83, while responsiveness to change scores at 6 months after intervention implementations were greater (P < 0.001) in two out of three units. Conclusion. The GRS-C exhibits satisfactory metrics, supporting its use in a national quality initiative aimed at improving processes in endoscopy units. Data collection from more units and linking to actual patient outcomes are required to ensure that GRS-C implementation facilitates improved patient care.

Longitudinal Rates of Colon Cancer Screening Use in Winnipeg, Canada: The Experience of a Universal Health-Care System with an Organized Colon Screening Program

OBJECTIVES

We examined trends in colorectal cancer (CRC) screening (fecal occult blood test (FOBT), colonoscopy, and flexible sigmoidoscopy (FS)) and differences in CRC screening by income in a population with an organized CRC screening program and universal health-care coverage.

METHODS

Individuals who had an FOBT, colonoscopy, or FS were identified from the provincial Physician Claims database and the population-based colon cancer screening registry. Trends in age-standardized rates were determined. Logistic regression was performed to explore the association between CRC screening and income quintiles by year.

RESULTS

Up-to-date CRC screening (FOBT, colonoscopy, or FS) increased over time for men and women, all age groups, and all income quintiles. Up-to-date CRC screening was very high among 65- to 69- and 70- to 74-year-olds (70% and 73%, respectively). There was a shift toward the use of an FOBT for CRC screening for individuals in the lower income quintiles. The disparity in colonoscopy/FS coverage by income quintile was greater in 2012 than in 1995. Overall, there was no reduction in disparities by income in up-to-date CRC screening nor did the rate of increase in up-to-date CRC screening or FOBT use change after the introduction of the organized provincial CRC screening program.

CONCLUSIONS

CRC screening is increasing over time for both men and women and all age groups. However, a disparity in up-to-date CRC screening by income persisted even with an organized CRC screening program in a universal health-care setting.

Polyethylene glycol versus sodium picosulfalte bowel preparation in the setting of a colorectal cancer screening program

BACKGROUND

Adequate bowel preparation for colonoscopy is an important predictor of colonoscopy quality.

OBJECTIVE

To determine the difference in terms of effectiveness between different existing colon cleansing products in the setting of a colorectal cancer screening program.

METHODS

The records of consecutive patients who underwent colonoscopy at the Montreal General Hospital (Montreal, Quebec) between April 2013 and April 2014 were retrospectively extracted from a dedicated electronic digestive endoscopic institutional database.

RESULTS

Overall, 2867 charts of patients undergoing colonoscopy were assessed, of which 1130 colonoscopies were performed in a screening setting; patients had adequate bowel preparation in 90%. Quality of preparation was documented in only 61%. Bowel preparation was worse in patients receiving sodium picosulfate (PICO) alone compared with polyethylene glycol, in a screening setting (OR 0.3 [95% CI 0.2 to 0.6]). Regardless of the preparation type, the odds of achieving adequate quality cleansing was 6.6 for patients receiving a split-dose regimen (OR 6.6 [95% CI 2.1 to 21.1]). In multivariable analyses, clinical variables associated with inadequate bowel preparation in combined population were use of PICO, a nonsplit regimen and inpatient status. The polyp detection rate was very high (45.6%) and was correlated with withdrawal time.

CONCLUSION

Preparation quality needs to be more consistently included in the colonoscopy report. Split-dose regimens increased the quality of colon cleansing across all types of preparations and should be the preferred method of administration. Polyethylene glycol alone provided better bowel cleansing efficacy than PICO in a screening setting but PICO remains an alternative in association with an adjuvant.

Small-area variation in screening for cancer, glucose and cholesterol in Ontario: a cross-sectional study

BACKGROUND

Screening for cervical, breast and colon cancers, and elevations of cholesterol and glucose, reduces premature cause-specific mortality from these cancers and circulatory diseases. Despite primary care reforms and incentives, and promotion of cancer-screening programs among individuals, participation is suboptimal. We aimed to examine participation as of Dec. 31, 2011, by factors of deprivation, demographics and primary care at the small-area level.

METHODS

From health care administrative databases, we identified people eligible for each screening test, and their participation, in each dissemination area (referred to as small areas, n = 18 950) in Ontario. We calculated rates for each test among small areas (overall and stratified by demographic, socioeconomic and primary care descriptors) and stratified by sex for all tests combined. We loaded all data into a geographic information system. Funnel plots were generated showing the percentage of eligible people who completed screening for all tests by small area, stratified by sex. Overall and stratified screening prevalence ratios were calculated among small areas.

RESULTS

Among small areas, the mean and SD for participation in all tests combined was 31.6% (SD 11.0%) for women and 41.2% (SD 12.0%) for men. Screening prevalence among small areas, for each test and for all tests combined, overall and stratified by sex, declined with decreasing percentage with high school completion, decreasing socioeconomic quintile, and decreasing percentage with an identifiable primary care physician.

INTERPRETATION

Our results show that the rate of participation in all eligible screening tests among small areas is much lower than the rate of participation in any one particular test. This finding has implications for the design and implementation of strategies to improve rates of screening.

Recent trends in breast, cervical, and colorectal cancer screening test utilization in Canada, using self-reported data from 2008 and 2012

In Canada, self-reported data from the Canadian Community Health Survey 2008 and 2012 provide an opportunity to examine overall utilization of breast, cervical, and colorectal cancer screening tests for both programmatic and opportunistic screening. Among women 50-74 years of age, utilization of screening mammography was stable (62.0% in 2008 and 63.0% in 2012). Pap test utilization for women 25-69 years of age remained high and stable across Canada in 2008 and 2012 (78.9% in 2012). The percentage of individuals 50-74 years of age who reporting having at least 1 fecal test within the preceding 2 years increased in 2012 (to 23.0% from 16.9% in 2008), but remains low. Stable rates of screening mammography utilization (about 30%) were reported in 2008 and 2012 among women 40-49 years of age, a group for which population-based screening is not recommended. Although declining over time, cervical cancer screening rates were high for women less than 25 years of age (for whom screening is not recommended). Interestingly, an increased percentage of women 70-74 years of age reported having a Pap test. In 2012, a smaller percentage of women 50-69 years of age reported having no screening test (5.9% vs. 8.5% in 2008), and more women reported having the three types of cancer screening tests (19.0% vs. 13.2%). Efforts to encourage use of screening within the recommended average-risk age groups are needed, and education for stakeholders about the possible harms of screening outside those age groups has to continue.

Evaluation of the analytical performance of the novel NS-Prime system and examination of temperature stability of fecal transferrin compared with fecal hemoglobin as biomarkers in a colon cancer screening program

OBJECTIVE

To examine the analytical aspects of fecal transferrin (Tf) and hemoglobin (Hb) measured on the NS-Prime analyzer for use in a colon cancer screening program.

DESIGNS AND METHODS

Method evaluation and temperature stability studies for fecal Tf and Hb were completed. A method comparison was carried out against the NS-Plus system using samples collected from 254 screening program participants. A further 200 samples were analyzed to help determine suitable reference limits for fecal Tf using these systems.

RESULTS

The assay for fecal Tf showed acceptable linearity, precision, and recovery, and showed minimal carryover with low potential for impact by the prozone effect. The 95th percentile for fecal Tf obtained for the reference population was 4.9 µg/g feces. The collection device sufficiently maintained fecal Tf and Hb stability for at least 7 days at room temperature, 4 °C, and -20 °C. Fecal Tf and Hb were most stable at 4 °C and -20 °C, but showed considerable loss (20-40%) of both proteins at 37 °C within the first 7 days. Mixing small amounts of blood into diluted fecal samples maintained at 37 °C for various time periods showed >50% loss of both proteins within 1 h of incubation.

CONCLUSIONS

The NS-Prime analyzer showed acceptable performance for fecal Tf and Hb. These studies suggest that use of both Tf and Hb together as biomarkers will result in higher positivity rates, but this may not be attributed to greater stability of Tf over Hb in human feces.

Colon Capsule Endoscopy for the Detection of Colorectal Polyps: An Evidence-Based Analysis

BACKGROUND

Colorectal cancer, a leading cause of mortality and morbidity in Ontario, can be prevented through early diagnosis and removal of precancerous polyps. Colon capsule endoscopy is a relatively new, minimally invasive test for detecting colorectal polyps.

OBJECTIVE

The objectives of this analysis were to evaluate the diagnostic accuracy and safety of colon capsule endoscopy for the detection of colorectal polyps among adult patients with signs or symptoms of colorectal cancer or with increased risk of colorectal cancer, and to compare colon capsule endoscopy with alternative procedures.

REVIEW METHODS

A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid EMBASE, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2006 and 2014. Data on diagnostic accuracy and safety were abstracted from included studies. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

RESULTS

The search yielded 2,189 citations. Five studies, all of which evaluated PillCam COLON 2 (PCC2), met the inclusion criteria. The per-patient sensitivity and specificity for detecting colorectal polyps were meta-analyzed. Colon capsule endoscopy, using PCC2, had a pooled sensitivity and specificity of 87% (95% confidence interval [CI] 77%-93%) and 76% (95% CI 60%-87%), respectively, for the detection of a colorectal polyp at least 6 mm in size (GRADE: very low). PCC2 had a pooled sensitivity and specificity of 89% (95% CI 77%-95%) and 91% (95% CI 86%-95%), respectively, for the detection of a colorectal polyp at least 10 mm in size (GRADE: low). One study directly compared PCC2 with computed tomographic (CT) colonography and found no statistically significant difference in accuracy (GRADE: low). Few adverse events were reported with PCC2; 3.9% of patients (95% CI 2.4%-6.5%) experienced adverse effects related to bowel preparation. Capsule retention was the most serious adverse event and occurred in 0.8% of patients (95% CI 0.2%-2.4%) (GRADE: very low).

CONCLUSIONS

In adult patients with signs, symptoms, or increased risk of colorectal cancer, there is low-quality evidence that colon capsule endoscopy using the PCC2 device has good sensitivity and specificity for detecting colorectal polyps. Low-quality evidence does not show a difference in accuracy between colon capsule endoscopy and CT colonography. There is very low-quality evidence that PCC2 has a good safety profile with few adverse events; capsule retention is the most serious complication.

Colon Capsule Endoscopy for the Detection of Colorectal Polyps: An Economic Analysis

BACKGROUND

Colorectal cancer is a leading cause of mortality and morbidity in Ontario. Most cases of colorectal cancer are preventable through early diagnosis and the removal of precancerous polyps. Colon capsule endoscopy is a non-invasive test for detecting colorectal polyps.

OBJECTIVES

The objectives of this analysis were to evaluate the cost-effectiveness and the impact on the Ontario health budget of implementing colon capsule endoscopy for detecting advanced colorectal polyps among adult patients who have been referred for computed tomographic (CT) colonography.

METHODS

We performed an original cost-effectiveness analysis to assess the additional cost of CT colonography and colon capsule endoscopy resulting from misdiagnoses. We generated diagnostic accuracy data from a clinical evidence-based analysis (reported separately), and we developed a deterministic Markov model to estimate the additional long-term costs and life-years lost due to false-negative results. We then also performed a budget impact analysis using data from Ontario administrative sources. One-year costs were estimated for CT colonography and colon capsule endoscopy (replacing all CT colonography procedures, and replacing only those CT colonography procedures in patients with an incomplete colonoscopy within the previous year). We conducted this analysis from the payer perspective.

RESULTS

Using the point estimates of diagnostic accuracy from the head-to-head study between colon capsule endoscopy and CT colonography, we found the additional cost of false-positive results for colon capsule endoscopy to be $0.41 per patient, while additional false-negatives for the CT colonography arm generated an added cost of $116 per patient, with 0.0096 life-years lost per patient due to cancer. This results in an additional cost of $26,750 per life-year gained for colon capsule endoscopy compared with CT colonography. The total 1-year cost to replace all CT colonography procedures with colon capsule endoscopy in Ontario is about $2.72 million; replacing only those CT colonography procedures in patients with an incomplete colonoscopy in the previous year would cost about $740,600 in the first year.

LIMITATIONS

The difference in accuracy between colon capsule endoscopy and CT colonography was not statistically significant for the detection of advanced adenomas (≥ 10 mm in diameter), according to the head-to-head clinical study from which the diagnostic accuracy was taken. This leads to uncertainty in the economic analysis, with results highly sensitive to changes in diagnostic accuracy.

CONCLUSIONS

The cost-effectiveness of colon capsule endoscopy for use in patients referred for CT colonography is $26,750 per life-year, assuming an increased sensitivity of colon capsule endoscopy. Replacement of CT colonography with colon capsule endoscopy is associated with moderate costs to the health care system.

Colonoscopy in Colorectal Cancer Screening: Current Aspects

Colonoscopy represents a very important diagnostic modality for screening for colorectal cancer, because it has the ability to both detect and effectively remove pro-malignant and malignant lesions. It is recommended by almost all international and national gastroenterology and cancer societies, as an initial screening modality or, following a positive fecal occult blood test, to be performed every 10 years in individuals of average risk starting from the age of 50. However, a significant problem is the so-called post-screening (interval) polyps and cancers found some years after the index colonoscopy. In order to reduce the rate of interval cancers it is extremely necessary to optimize the quality and effectiveness of colonoscopy. Bowel preparation is of paramount importance for both accurate diagnosis and subsequent treatment of lesions found on colonoscopy. The quality of bowel preparation could be significantly improved by splitting the dose regimens, a strategy that has been shown to be superior to single-dose regimen. A good endoscopic technique and optimal withdrawal time offering adequate time for inspection, would further optimize the rate of cecal intubation and the number of lesions detected. During the last years, sophisticated devices have been introduced that would further facilitate cecal intubation. The percentage of total colonoscopies is now super-passing the level of 95 % allowing the adenoma detection rate to be greater than the suggestive level of 25 % in men and 15 % in women. This review aims to provide the reader with the current knowledge concerning indications, usefulness, limitations and future perspectives of this probably most important screening technique for colorectal cancer available today.

Screening rates for colorectal cancer in Canada: a cross-sectional study

INTRODUCTION

Implementation of population-based colorectal cancer (CRC) screening programs should reduce disparities in participation in CRC screening. We estimated CRC screening rates in 2012 in Canada and assessed predictors of screening in provinces with and without well-established population-based screening programs.

METHODS

We used data from the Canadian Community Health Survey for 2012 to calculate the prevalence of up-to-date CRC screening, defined as fecal occult blood testing (FOBT) within 2 years before the survey or flexible sigmoidoscopy or colonoscopy within 10 years before the survey, or both. Weighted proportions of individuals with up-to-date screening were calculated and logistic regression analysis performed to assess predictors of up-to-date CRC screening, including differences in participation by income level.

RESULTS

The prevalence of up-to-date CRC screening among people 50-74 years of age in 2012 was 55.2%, ranging from 41.3% in the territories to 67.2% in the province of Manitoba. The rate for sigmoidoscopy or colonoscopy was 37.2% (highest in Ontario, at 43.3%), and for FOBT it was 30.1% (highest in Manitoba, at 51.7%). About 41% of those who had an FOBT also had a sigmoidoscopy or colonoscopy. Individuals in the highest income group were more likely than those in lower-income groups to be up to date with CRC screening, even in provinces with well-established population-based screening programs.

INTERPRETATION

More than half of Canadians were up to date with CRC screening in 2012, but there were large differences among provinces. Differences by income group in provinces with population-based screening programs need particular attention.

Awareness and uptake of family screening in patients diagnosed with colorectal cancer at a young age

Background. One-fifth of people who develop colorectal cancer (CRC) have a first-degree relative (FDR) also affected. There is a large disparity in guidelines for screening of relatives of patients with CRC. Herein we address awareness and uptake of family screening amongst patients diagnosed with CRC under age 60 and compare guidelines for screening. Study Design. Patients under age 60 who received surgical management for CRC between June 2009 and May 2012 were identified using pathology records and theatre logbooks. A telephone questionnaire was carried out to investigate family history and screening uptake among FDRs. Results. Of 317 patients surgically managed for CRC over the study period, 65 were under age 60 at diagnosis (8 deceased). The mean age was 51 (30–59). 66% had node positive disease. 25% had a family history of colorectal cancer in a FDR. While American and Canadian guidelines identified 100% of these patients as requiring screening, British guidelines advocated screening for only 40%. Of 324 FDRs, only 40.9% had been screened as a result of patient's diagnosis. Conclusions. Uptake of screening in FDRs of young patients with CRC is low. Increased education and uniformity of guidelines may improve screening uptake in this high-risk population.

The colorectal cancer mortality-to-incidence ratio as an indicator of global cancer screening and care

BACKGROUND

Disparities in cancer screening, incidence, treatment, and survival are worsening globally. The mortality-to-incidence ratio (MIR) has been used previously to evaluate such disparities.

METHODS

The MIR for colorectal cancer is calculated for all Organisation for Economic Cooperation and Development (OECD) countries using the 2012 GLOBOCAN incidence and mortality statistics. Health system rankings were obtained from the World Health Organization. Two linear regression models were fit with the MIR as the dependent variable and health system ranking as the independent variable; one included all countries and one model had the "divergents" removed.

RESULTS

The regression model for all countries explained 24% of the total variance in the MIR. Nine countries were found to have regression-calculated MIRs that differed from the actual MIR by >20%. Countries with lower-than-expected MIRs were found to have strong national health systems characterized by formal colorectal cancer screening programs. Conversely, countries with higher-than-expected MIRs lack screening programs. When these divergent points were removed from the data set, the recalculated regression model explained 60% of the total variance in the MIR.

CONCLUSIONS

The MIR proved useful for identifying disparities in cancer screening and treatment internationally. It has potential as an indicator of the long-term success of cancer surveillance programs and may be extended to other cancer types for these purposes.