Colorectal Cancer Screening in Average Risk Populations: Evidence Summary

Duration of risk reduction in colorectal cancer incidence and mortality after a complete colonoscopy in Ontario, Canada: a population-based cohort study

BACKGROUND

Colorectal cancer guidelines recommend screening colonoscopy every 10 years after a negative procedure. If risk reduction extends past 10 years, the recommended interval could be extended, reducing the burden on the individual and health-care system. We aimed to estimate the duration that patients remain at reduced risk of colorectal cancer incidence and mortality after a complete colonoscopy.

METHODS

We did a population-based cohort study of individuals aged 50-65 years between Jan 1, 1994, to Dec 31, 2017. We excluded individuals with previous exposure to colonoscopy or colorectal surgery, those previously diagnosed with colorectal cancer, or a history of hereditary or other bowel disorders. We followed up participants until Dec 31, 2018, and identified all colonoscopies performed in this time period. We used a 9-level time-varying measure of exposure, capturing time since last complete colonoscopy (no complete colonoscopy, ≤5 years, >5-10 years, >10-15 years, and >15 years) and whether an intervention was performed (biopsy or polypectomy). A Cox proportional hazards regression model adjusting for age, sex, comorbidity, residential income quintile, and immigration status was used to estimate the association between exposure to a complete colonoscopy and colorectal cancer incidence and mortality.

FINDINGS

5 298 033 individuals (2 609 060 [49·2%] female and 2 688 973 [50·8%] male; no data on ethnicity were available) were included in the cohort, with a median follow-up of 12·56 years (IQR 6·26-20·13). 90 532 (1·7%) individuals were diagnosed with colorectal cancer and 44 088 (0·8%) died from colorectal cancer. Compared with those who did not have a colonoscopy, the risk of colorectal cancer in those who had a complete negative colonoscopy was reduced at all timepoints, including when the procedure occurred more than 15 years earlier (hazard ratio [HR] 0·62 [95% CI 0·51-0·77] for female individuals and 0·57 [0·46-0·70] for male individuals. A similar finding was observed for colorectal cancer mortality, with lower risk at all timepoints, including when the procedure occurred more than 15 years earlier (HR 0·64 [95% CI 0·49-0·83] for female participants and 0·65 [0·50-0·83] for male participants). Those who had a colonoscopy with intervention had a significantly lower colorectal cancer incidence than those who did not undergo colonoscopy if the procedure occurred within 10 years for females (HR 0·70 [95% CI 0·63-0·77]) and up to 15 years for males (0·62 [(0·53-0·72]).

INTERPRETATION

Compared with those who do not receive colonoscopy, individuals who have a negative colonoscopy result remain at lower risk for colorectal cancer incidence and mortality more than 15 years after the procedure. The current recommendation of repeat screening at 10 years in these individuals should be reassessed.

FUNDING

Canadian Institutes of Health Research.

Colorectal Cancer: Epidemiology, Risk Factors, and Prevention

Colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer mortality worldwide. There are disparities in the epidemiology of CRC across different populations, most probably due to differences in exposure to lifestyle and environmental factors related to CRC. Prevention is the most effective method for controlling CRC. Primary prevention includes determining and avoiding modifiable risk factors (e.g., alcohol consumption, smoking, and dietary factors) as well as increasing protective factors (e.g., physical activity, aspirin). Further studies, especially randomized, controlled trials, are needed to clarify the association between CRC incidence and exposure to different risk factors or protective factors. Detection and removal of precancerous colorectal lesions is also an effective strategy for controlling CRC. Multiple factors, both at the individual and community levels (e.g., patient preferences, availability of screening modalities, costs, benefits, and adverse events), should be taken into account in designing and implementing CRC screening programs. Health policymakers should consider the best decision in identifying the starting age and selection of the most effective screening strategies for the target population. This review aims to present updated evidence on the epidemiology, risk factors, and prevention of CRC.

Deaths and cardiopulmonary events following colorectal cancer screening-A systematic review with meta-analyses

BACKGROUND

Colorectal cancer screening programmes (CRCSPs) are implemented worldwide despite recent evidence indicating more physical harm occurring during CRCSPs than previously thought. Therefore, we aimed to review the evidence on physical harms associated with endoscopic diagnostic procedures during CRCSPs and, when possible, to quantify the risk of the most serious types of physical harm during CRCSPs, i.e. deaths and cardiopulmonary events (CPEs).

METHODS

Systematic review with descriptive statistics and random-effects meta-analyses of studies investigating physical harms following CRCSPs. We conducted a systematic search in the literature and assessed the risk of bias and the certainty of the evidence.

RESULTS

We included 134 studies for review, reporting findings from 151 unique populations when accounting for multiple screening interventions per study. Physical harm can be categorized into 17 types of harm. The evidence was very heterogeneous with inadequate measurement and reporting of harms. The risk of bias was serious or critical in 95% of assessments of deaths and CPEs, and the certainty of the evidence was very low in all analyses. The risk of death was assessed for 57 populations with large variation across studies. Meta-analyses indicated that 3 to 23 deaths occur during CRCSPs per 100,000 people screened. Cardiopulmonary events were assessed for 55 populations. Despite our efforts to subcategorize CPEs into 17 distinct subtypes, 41% of CPE assessments were too poorly measured or reported to allow quantification. We found a tendency towards lower estimates of deaths and CPEs in studies with a critical risk of bias.

DISCUSSION

Deaths and CPEs during CRCSPs are rare, yet they do occur during CRCSPs. We believe that our findings are conservative due to the heterogeneity and low quality of the evidence. A standardized system for the measurement and reporting of the harms of screening is warranted.

TRIAL REGISTRATION

PROSPERO Registration number CRD42017058844.

Developing a Health Equity Impact Assessment 'Indigenous Lens Tool' to address challenges in providing equitable cancer screening for indigenous peoples

BACKGROUND

In spite of past efforts to increase screening uptake, the rates of screening-detectable cancers including breast, cervical, colorectal and lung are rising among Indigenous persons in Ontario compared to other Ontarians. The Ontario Ministry of Health has an equity framework, the Health Equity Impact Assessment (HEIA) Tool, that was developed to guide organizations in the provision of more equitable health and social services. Although the HEIA Tool identifies that the health of Indigenous persons may benefit from more equitable provision of health and social services, it provides very little specific guidance on how to apply the HEIA Tool in a culturally relevant way to policies and programs that may impact Indigenous peoples.

DISCUSSION

Guided by the Calls to Action from the Truth and Reconciliation Commission of Canada and the United Nations Declaration on the Rights of Indigenous Peoples, an Indigenous Lens Tool was developed through a collaborative and iterative process with stakeholders at Cancer Care Ontario and with representatives from Indigenous community-based organizations. The Indigenous Lens Tool consists of four scenarios, with supporting documentation that provide context for each step of the HEIA Tool and thereby facilitate application of the equity framework to programs and policies. The document is in no way meant to be comprehensive or representative of the diverse health care experiences of Indigenous peoples living in Canada nor the social determinants that surround health and well-being of Indigenous peoples living in Canada. Rather, this document provides a first step to support development of policies and programs that recognize and uphold the rights to health and well-being of Indigenous peoples living in Canada.

CONCLUSIONS

The Indigenous Lens Tool was created to facilitate implementation of an existing health equity framework within Cancer Care Ontario (now Ontario Health). Even though the Indigenous Lens Tool was created for this purpose, the principles contained within it are translatable to other health and social service policy applications.

The risk of bleeding and perforation from sigmoidoscopy or colonoscopy in colorectal cancer screening: A systematic review and meta-analyses

INTRODUCTION

Physical harm from Colorectal Cancer Screening tends to be inadequately measured and reported in clinical trials. Also, studies of ongoing Colorectal Cancer Screening programs have found more frequent and severe physical harm from screening procedures, e.g., bleeding and perforation, than reported in previous trials. Therefore, the objectives of the study were to systematically review the evidence on the risk of bleeding and perforation in Colorectal Cancer Screening.

DESIGN

Systematic review with descriptive statistics and random-effects meta-analyses.

METHODS

We systematically searched five databases for studies investigating physical harms related to Colorectal Cancer Screening. We assessed the internal and the external validity using the ROBINS-I tool and the GRADE approach. Harm estimates was calculated using mixed Poisson regression models in random-effect meta-analyses.

RESULTS

We included 89 studies. Reporting and measurement of harms was inadequate in most studies. In effect, the risk of bias was critical in 97.3% and serious in 98.3% of studies. All GRADE ratings were very low. Based on severe findings with not-critical risk of bias and 30 days follow-up, the risk of bleedings per 100,000 people screened were 8 [2;24] for sigmoidoscopy, 229 [129;408] for colonoscopy following fecal immunochemical test, 68 [39;118] for once-only colonoscopy, and 698 [443;1045] for colonoscopy following any screening tests. The risk of perforations was 88 [56;138] for colonoscopy following fecal immunochemical test and 53 [25;112] for once-only colonoscopy. There were no findings within the subcategory severe perforation with long-term follow-up for colonoscopy following any screening tests and sigmoidoscopy.

DISCUSSION

Harm estimates varied widely across studies, reporting and measurement of harms was mostly inadequate, and the risk of bias and GRADE ratings were very poor, collectively leading to underestimation of harm. In effect, we consider our estimates of perforation and bleeding as conservative, highlighting the need for better reporting and measurement in future studies.

TRIAL REGISTRATION

PROSPERO registration number: CRD42017058844.

Implementation of an organized colorectal cancer screening program through quantitative fecal immunochemical test followed by colonoscopy in an urban low-income community: Guidance and strategies

Fecal Immunochemical Test (FIT) followed by a colonoscopy is an efficacious strategy to improve the adenoma detection rate and Colorectal Cancer (CRC). There is no organized national screening program for CRC in Brazil. The aim of this research was to describe the implementation of an organized screening program for CRC through FIT followed by colonoscopy, in an urban low-income community of São Paulo city. The endpoints of the study were: FIT participation rate, FIT positivity rate, colonoscopy compliance rate, Positive Predictive Values (PPV) for adenoma and CRC, and the rate of complications. From May 2016 to October 2019, asymptomatic individuals, 50-75 years old, received a free kit to perform the FIT. Positive FIT (≥ 50 ng/mL) individuals were referred to colonoscopy. 10,057 individuals returned the stool sample for analysis, of which (98.2%) 9,881 were valid. Women represented 64.8% of the participants. 55.3% of individuals did not complete elementary school. Positive FIT was 7.8% (776/9881). The colonoscopy compliance rate was 68.9% (535/776). There were no major colonoscopy complications. Adenoma were detected in 63.2% (332/525) of individuals. Advanced adenomatous lesions were found in 31.4% (165/525). CRC was diagnosed in 5.9% (31/525), characterized as adenocarcinoma: in situ in 3.2% (1/31), intramucosal in 29% (9/31), and invasive in 67.7% (21/31). Endoscopic treatment with curative intent for CRC was performed in 45.2% (14/31) of the cases. Therefore, in an urban low-income community, an organized CRC screening using FIT followed by colonoscopy ensued a high participation rate, and high predictive positive value for both, adenoma and CRC.

Provincial variation in colorectal cancer screening adherence in Canada; evidence from the Canadian Partnership for Tomorrow's Health

Introduction

Although colorectal cancer (CRC) screening program is proven to reduce CRC incidence and mortality, understanding patterns and predictors of suboptimal adherence in screening program requires further investigation in Canada.

Methods

We used self-reported data from five regional cohorts of the Canadian Partnership for Tomorrow's Health (CanPath), namely the BC Generations Project (BCGP), Alberta's Tomorrow Project (ATP), the Ontario Health Study (OHS), Quebec's CARTaGENE, and the Atlantic Partnership for Tomorrow's Health Study (Atlantic PATH). We stratified participants into the following four risk categories: 1) age 50-74 years, 2) family history in a first-degree relative, 3) personal history of chronic inflammatory bowel disease and/or polyps, and 4) co-existence of personal risk and family history. Multivariable logistic regression was used to identify predictors of adherence to the screening guidelines.

Results

Adherence to CRC screening varied considerably between regions, ranging from 16.6% in CARTaGENE to 47.7% in OHS. Compared to the largest cohort OHS, the likelihood of non-adherence to CRC screening was significantly higher in BCGP (OR 1.15, 95% CI 1.11-1.19), the Atlantic PATH (OR 1.90, 95% CI 1.82-1.99) and CARTaGENE (OR 5.10, 95% CI 4.85-5.36). Low physical activity, current smoking, presence of personal risk, family history of CRC significantly reduced the likelihood of adherence to screening recommendations.

Discussion/conclusion

Compared to the national target of ≥ 60% for participation in CRC screening, adherence to regular CRC screening was suboptimal in this cohort of Canadians and varied by region. Further efforts are needed to identify the specific barriers to screening adherence in different provinces and across risk categories.

Biopsy of Non-tumor Sites After Biopsy of a Colorectal Cancer is not Associated With Metachronous Cancers: A Case-control Study

BACKGROUND & AIMS

Recent research has demonstrated biologic plausibility for iatrogenic tumor seeding via colonoscopy as a cause of metachronous colorectal cancers (CRC). This study evaluated the association between biopsy of non-tumor sites after CRC biopsy and risk of metachronous CRC in a large community-based health care organization.

METHODS

This was a retrospective case-control study of adults with an initial CRC diagnosed by colonoscopy between January 2006 and June 2018 who underwent curative resection. Cases developed a second primary (metachronous) CRC diagnosed 6 months to 4 years after the initial CRC, and were matched by age, sex, diagnosis of inflammatory bowel disease, race, and ethnicity with up to 5 controls without a second CRC diagnosis. The exposure was biopsy in the colonic segment of the metachronous CRC (or corresponding segment in controls) after tumor biopsy, ascertained with blinding to case status. Associations were evaluated using conditional logistic regression and adjusted for potential cofounders.

RESULTS

Among 14,119 patients diagnosed with an initial CRC during colonoscopy, 107 received a second CRC diagnosis. After exclusions for recurrent or synchronous CRC, 45 cases and 212 controls were included. There was no significant association between biopsy of non-tumor sites after initial CRC biopsy and risk of metachronous CRC in the segment of the additional biopsy site (adjusted odds ratio, 2.29; 95% confidence interval, 0.77-6.81).

CONCLUSIONS

Metachronous cancers are not significantly associated with biopsy of non-tumor sites after biopsy of the primary cancer. Although the sample size does not allow definite exclusion of any association, these findings do not support iatrogenic tumor seeding as a common risk factor for metachronous CRC.

Should we screen for colorectal cancer in people aged 75 and over? A systematic review - collaborative work of the French geriatric oncology society (SOFOG) and the French federation of digestive oncology (FFCD)

BACKGROUND

We have done a systematic literature review about CRC Screening over 75 years old in order to update knowledge and make recommendations.

METHODS

PUBMED database was searched in October 2021 for articles published on CRC screening in the elderly, and generated 249 articles. Further searches were made to find articles on the acceptability, efficacy, and harms of screening in this population, together with the state of international guidelines.

RESULTS

Most benefit-risk data on CRC screening in the over 75 s derived from simulation studies. Most guidelines recommend stopping cancer screening at the age of 75. In private health systems, extension of screening up to 80-85 years is, based on the life expectancy and the history of screening. Screening remains effective in populations without comorbidity given their better life-expectancy. Serious adverse events of colonoscopy increase with age and can outweigh the benefit of screening. The great majority of reviews concluded that screening between 75 and 85 years must be decided case by case.

CONCLUSION

The current literature does not allow Evidence-Based Medicine propositions for mass screening above 75 years old. As some subjects over 75 years may benefit from CRC screening, we discussed ways to introduce CRC screening in France in the 75-80 age group. IRB: An institutional review board composed of members of the 2 learned societies (SOFOG and FFCD) defined the issues of interest, followed the evolution of the work and reviewed and validated the report.

A Real-Time Endoscope Motion Tracker

OBJECTIVE

In colonoscopy, it is desirable to accurately localize the position of the endoscope's distal tip. Current tip localization techniques are not sufficient for recording the position and movement of the tip, nor is its rotation measured. We hypothesize that integration of multiple tracking modalities can effectively record the endoscope's motion in real time and continuously corrects cumulative errors.

METHODS

A dual modality tracking method is developed to measure the motion of the endoscope's insertion tube in real time, including insertion length, rotation angle, and their velocities. Optical trackballs were used to measure the endoscope insertion tube's motion and cameras were used to correct cumulative errors.

RESULTS

The accuracy of insertion length and rotational angle were measured. For speeds ≤ 10 mm/s, the median and 90th percentile insertion position errors were 0.88 mm and 2.2 mm, respectively. The insertion position error increases with the speed, reaching a maximum of 10 mm for speeds < 40 mm/s. 11° and 21° were the median and 90th percentile rotation angle errors for angular speeds < 40°/s. Cumulative errors are sufficiently reduced by the imaging modality.

CONCLUSION

The prototype device can precisely measure an unmodified endoscope's position, rotation, and motion in real time without significant accumulative error. The prototype device is small and compatible with existing commercial endoscopes as an add-on accessory, which could be used for reporting, localizing the lesions in follow up procedures, operational guidance, quality assurance, and training. Clinical and Translational Impact Statement-This preclinical research develops an endoscope tracker that can be integrated into colonoscopy training, automatically record endoscope motion, and be further developed to improve polyp and tumor localization during colonoscopy.

Screening for Colorectal Cancer

Colorectal cancer (CRC) is the second-leading cause of cancer death in the United States. Screening reduces CRC incidence and mortality. 2021 US Preventive Service Task Force (USPSTF) guidelines and available evidence support routine screening from ages 45 to 75, and individualized consideration of screening ages 76 to 85. USPSTF guidelines recommend annual guaiac fecal occult blood testing, annual fecal immunochemical testing (FIT), annual to every 3-year multitarget stool DNA-FIT, every 5-year sigmoidoscopy, every 10-year sigmoidoscopy with annual FIT, every 5-year computed tomographic colonography, and every 10-year colonoscopy as options for screening. The "best test is the one that gets done."

Quality Indicators for the Detection and Removal of Colorectal Polyps and Interventions to Improve Them

Modifiable risk factors for postcolonoscopy colorectal cancer include suboptimal lesion detection (missed neoplasms) and inadequate lesion removal (incomplete polypectomy) during colonoscopy. Competent detection and removal of colorectal polyps are thus fundamental to ensuring adequate colonoscopy quality. Several well-researched quality metrics for polyp detection have been implemented into clinical practice, chief among these the adenoma detection rate. Less data are available on quality indicators for polyp removal, which currently include complete resection rates and skills assessment tools. This review summarizes the available literature on quality indicators for the detection and removal of colorectal polyps, as well as interventions to improve them.

Using Facebook to promote the uptake of colorectal cancer screening

Background

The use of social media presents a unique opportunity for cancer screening programs to motivate individuals to get screened. However, we need a better understanding of what types of social media messages for colorectal cancer (CRC) screening are preferred. The objective of this study was to develop social media messages promoting CRC screening uptake to identify messages preferred by the target audience.

Methods

We conducted a qualitative descriptive study and collected data through focus groups with Facebook users of screen-eligible age. Participants were presented with social media messages and asked to provide feedback. Messages were informed by the Health Belief Model, current evidence regarding screening communication and health communication and social media best practices. Focus groups were audio-recorded and transcribed and analysis was completed by two independent coders. If messages generated sufficient discussion, we developed a recommendation regarding the use of the message in a future social media campaign. Recommendations included: strongly consider using this message, consider using this message, proceed with caution, and do not use this message. General considerations about social media campaigns were also noted.

Results

A total of 45 individuals participated in six focus groups. We developed recommendations for 7 out of the 18 messages tested; 1 was classified as strongly consider using this message, 4 as consider using this message and 2 as proceed with caution. The data suggest that participants preferred social media messages that were believed to be credible, educational, and with a positive or reassuring tone. Preferred messages tended to increase awareness about CRC risk and screening and prompted participants to ask questions, and to want to learn more about what they could do to lower their risk. Messages that were viewed as humorous, strange or offensive or that had a negative or excessively fearful tone were less well received by study participants.

Conclusions

Facebook users prefer social media messages for CRC that have a positive or reassuring tone, are educational, and that have a credible ad sponsor. Campaign planners should proceed with caution when considering messages that use humor or a fearful tone to avoid undermining their campaign objectives.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12732-w.

Two randomized controlled trials for colorectal cancer screening invitations developed using a behavioral science approach

The effectiveness of behaviorally informed, targeted invitations to standard invitations and to no invitation (control arm, primary analysis) were compared in the context of an organized colorectal cancer (CRC) screening program. Two multi-arm, pragmatic randomized controlled trials in men (arms: male-specific, unisex, standard invitation, or no invitation) and in women (arms: unisex, standard invitation, or no invitation), were conducted in Ontario, Canada. Eligible persons aged 50-74, due for CRC screening, were randomized. Primary and secondary outcomes were completion of the guaiac fecal occult blood test (gFOBT) and uptake of any colorectal test, respectively, within 5 months of mailing. Impact of invitation type was assessed using logistic regression. Letters were mailed to 75,810 men and women; 38,673 males and 34,453 females were included in the analyses. Men who received the male-specific letter were most likely to screen with gFOBT compared to controls (odds ratio (OR) 7·24, 95% CI: 5·77, 9·09), followed by those receiving the unisex letter (OR 6·75, 95% CI: 5·37, 8·47) and the standard letter (OR 5·99, 95% CI: 4·76, 7·53). Women who received the unisex letter were most likely to be screened with gFOBT compared to controls (OR 7·07, 95% CI: 5·83, 8·59), followed by those receiving the standard letter (OR 6·76, 95% CI: 5·56, 8·21). In both trials, the findings were similar for the secondary outcome. Mailed invitations were effective for both men and women. With greater targeting using the behaviorally informed invitations, the magnitude of benefit relative to no invitation appeared to increase. (ClinicalTrials.gov, NCT02364895).

Colorectal Cancer Screening - Approach, Evidence, and Future Directions

Colorectal Cancer ScreeningScreening for colorectal cancer is widespread and successful but screening programs across the globe differ in their recommendations. In this article, Helsingen and Kalager review the evidence for different approaches to colorectal cancer screening and propose a framework for the evaluation of screening programs going forward.

Risk-stratified strategies in population screening for colorectal cancer

Colorectal cancer (CRC) screening has been demonstrated to reduce CRC incidence and mortality. However, besides such benefits, CRC screening is also associated with potential harmful effects. In an ideal world, screening would only be directed to the small proportion of the population that might potentially benefit. Risk‐based screening can be seen as a first step towards this ideal world, by redistributing screening resources from low‐risk to high‐risk individuals. In theory, this should result in scarce resources being used in individuals who benefit most, while intensity of screening is reduced in individuals who benefit less, hence improving the benefit‐harm ratio among all invitees. Available strategies that have been proposed for risk‐based CRC screening include using information on age, sex, prior screening history, lifestyle and/or genetic information. Implementation of risk‐based screening requires careful consideration of reliable risk prediction models, participation with screening and informed decision‐making. While it is important to recognise the limitations of current approaches, available evidence suggests that it might be feasible to start planning the introduction of tailored strategies within screening programmes. Implementing risk‐based screening based on age, sex and prior screening history alone would already represent a substantial improvement over current uniform screening approaches. We propose that it is time that screening programmes start there and continue striving towards more comprehensive approaches embedding primary prevention as an effective approach to lower risk for everyone.

Health Policy as a Barrier to First Nations Peoples' Access to Cancer Screening

Background:

First Nations peoples in Ontario are facing increasing rates of cancer and have been found to have poorer survival. Cancer screening is an important strategy to improve cancer outcomes; yet, Indigenous people in Canada are less likely to participate in screening. Ontario has established organized breast, cervical and colorectal cancer screening programs; this paper examines the health policy context that informs these programs for First Nations peoples in the province.

Method:

This paper follows an embedded multiple-case study design, drawing upon a document review to outline the existing policy context and on key informant interviews to explore the aforementioned context from the perspective of stakeholders.

Results:

Policies created by agencies operating across federal, regional and provincial levels impact First Nations peoples' access to screening. Interviews identified issues of jurisdictional ambiguity, appropriateness of program design for First Nations persons and lack of cultural competency as barriers to participation in screening.

Conclusion:

Federal, provincial and regional policy makers must work in collaboration with First Nations peoples to overcome barriers to cancer screening created and sustained by existing policies.

Accurate measurement of colorectal polyps using computer-aided analysis

INTRODUCTION

As we know, the majority of colorectal cancers are thought to evolve from colorectal adenomas. In this study, we explored the use of Computer-aided diagnosis (CAD) in the detection of colorectal polyps and the estimation of their sizes, which is important for the diagnosis and management of colorectal cancer.

MATERIALS AND METHODS

As the distance between colonoscopy and lesion increases, magnification tends to decrease. Therefore, the size of colorectal polyps can be calculated by taking into account the captured image and the shooting distance. In this study, the fitting curve of the magnification of electronic colonoscopy was obtained by simulating intestinal tract and polyps in vitro. Then, the distance was artificially controlled in the endoscopic operation, and the image was taken at a preset distance. The CAD system was then trained on the overall shape of colorectal polyps. Image segmentation was employed to accurately identify colorectal polyps. Finally, on the basis of the magnification factor, the real value of polyps was predicted from the shooting distance and the segmentation image size.

RESULTS

The CAD system can automatically calculate the range of colorectal polyps and calculate the true size of the colorectal polyps according to the magnification of the corresponding distance.

CONCLUSIONS

In this study, we developed a method of accurately estimating the size of colorectal polyps. This approach is compatible with many devices, which would expand its range of applications. This method has the potential for application in other areas of clinical diagnosis.

When Should We Let Colorectal Cancer Screening Get Personal?

Although screening reduces colorectal cancer (CRC) incidence and related mortality, national CRC screening rates remain suboptimal. Identifying strategies to improve screening rates remains an area of intense focus, and previous literature supports an association between the perceived risk of CRC and a likelihood or intent to complete screening. However, risk estimation alone through the validated National Cancer Institute Colorectal Cancer Risk Assessment Tool does not improve screening uptake compared with general education. Future studies should couple risk estimation with patient navigation and decision support aids to build upon our existing armamentarium of effective interventions.

Association between improved adenoma detection rates and interval colorectal cancer rates after a quality improvement program

BACKGROUND AND AIMS

Although colonoscopy reduces colorectal cancer (CRC) risk, interval CRCs (iCRCs) still occur. We aimed to determine iCRC incidence, assess the relationship between adenoma detection rates (ADRs) and iCRC rates, and evaluate iCRC rates over time concomitant with initiation of an institutional colonoscopy quality improvement (QI) program.

METHODS

We performed a retrospective cohort study of patients who underwent colonoscopy at an academic medical center (January 2003 to December 2015). We identified iCRCs through our data warehouse and reviewed charts to confirm appropriateness for study inclusion. iCRC was defined as a cancer diagnosed 6 to 60 months and early iCRC as a cancer diagnosed 6 to 36 months after index colonoscopy. We measured the relationship between provider ADRs and iCRC rates and assessed iCRC rates over time with initiation of a QI program that started in 2010.

RESULTS

A total of 193,939 colonoscopies were performed over the study period. We identified 186 patients with iCRC. The overall iCRC rate was .12% and the early iCRC rate .06%. Average-risk patients undergoing colonoscopy by endoscopists in the highest ADR quartile (34%-52%) had a 4-fold lower iCRC risk (relative risk, .23; 95% confidence interval, .11-.48) than those undergoing colonoscopy by endoscopists in the lowest quartile (12%-21%). After QI program initiation, overall iCRC rates improved from .15% to .08% (P < .001) and early iCRC rates improved from .07% to .04% (P = .004).

CONCLUSIONS

We confirmed that iCRC rate is inversely correlated with provider ADR. ADRs increased and iCRC rates decreased over time, concomitant with a QI program focused on split-dose bowel preparation, quality metric measurement, provider education, and feedback. iCRC rate measurement should be considered a feasible, outcomes-driven institutional metric of colonoscopy quality.

Uptake of Colorectal Cancer Screening by Physicians Is Associated With Greater Uptake by Their Patients

BACKGROUND & AIMS

Physicians' own screening practices might affect screening in their patients. We conducted a population-based study to evaluate whether family physicians who underwent colorectal cancer testing were more likely to have patients who underwent colorectal cancer testing.

METHODS

We collected demographic and health care information on residents of Ontario, Canada from administrative databases; the sample was restricted to individuals at average risk of colorectal cancer who were 52-74 years old as of April 21, 2016. We obtained a list of all registered physicians in the province; physicians (n = 11,434) were matched with nonphysicians (n = 45,736) on age, sex, and residential location. Uptake of colorectal tests was defined by a record of a fecal occult blood test in the past 2 years, flexible sigmoidoscopy in the past 5 years, or colonoscopy in the past 10 years. Patients were assigned to family physicians based on billing claim frequency, and then the association between colorectal testing in family physicians and their patients was examined using a modified Poisson regression model.

RESULTS

Uptake of colorectal tests by physicians and nonphysicians (median age 60 years; 71% men) was 67.9% (95% confidence interval [CI], 67.0%-68.7%) and 66.6% (95% CI, 66.2%-67.1%), respectively. Physicians were less likely than nonphysicians to undergo fecal occult blood testing and were more likely to undergo colonoscopy; prevalence ratios were 0.44 (95% CI, 0.42-0.47) and 1.24 (95% CI, 1.22-1.26), respectively. Uptake of colorectal tests by family physicians was associated with greater uptake by their patients (adjusted prevalence ratio, 1.10; 95% CI, 1.08-1.12).

CONCLUSIONS

Approximately one-third of physicians and nonphysicians are overdue for colorectal cancer screening. Patients are more likely to be tested if their family physician has been tested. There is an opportunity for physicians to increase their participation in colorectal cancer screening, which could, in turn, motivate their patients to undergo screening.

The colon cancer screening behaviours survey for South Asians: a pilot study of feasibility and psychometric evaluation

PURPOSE

The purpose of the study was to pilot test the English and Urdu version of the Colon Cancer Screening Behaviours Survey among South Asians in Canada. The first objective was to evaluate feasibility of administration, data collection using computer assisted personal interviewing software on a tablet, and response burden. The second objective was to examine the prevalence of colorectal cancer screening among South Asians and evaluate the psychometric properties of sub-scales in the survey.

METHODS

Purposive, network and snowball sampling were used to recruit participants for this cross-sectional study. Interviewer-led administration of the Colon Cancer Screening Behaviours Survey was conducted across two cities in Ontario, Canada. Qualitative data analysis assessed feasibility; and sub-scales were evaluated through principal component analysis, item-scale correlations, and construct validity using multiple linear and logistic regression.

RESULTS

A total of 328 South Asians participated, 47% Urdu speaking, and 53% English speaking. There was a 23% refusal rate to participate. Feasibility identified: (1) successful recruitment despite reasons for refusal; (2) problematic items and response categories; and (3) computer/tablet limitations. Principal component analysis identified 14 components that explained 68.7% of total variance; 34 items were retained after factor analysis. Internal consistency of 4 scales ranged from 0.79-0.91. There were significant differences in perceived barriers scale scores (- 12.21; 95% CI, - 17.13 to - 7.28; p <  0.0001) between those who participated and those who did not participate in screening. No association was found with years of residence and uptake of screening after adjustment (OR 0.91 (0.46-1.79), p = 0.783).

CONCLUSIONS

Recruitment and data collection methods are feasible among South Asians if functionality of the tablet selected is improved. The Colon Cancer Screening Behaviours Survey was finalized and retained items in sub-scales demonstrated good psychometric properties to assess behaviours for colon cancer screening among South Asians in Canada. The interviewer-led survey may be used by public health, cancer care or other health practitioners to describe or predict colorectal cancer screening behaviours among South Asians in similar settings or adapted and tested in other contexts.

Social media and mobile health technology for cancer screening: a systematic review and meta-analysis protocol

INTRODUCTION

Cancer is one of the leading causes of death globally and many jurisdictions have developed population-based cancer screening programmes to reduce the public health burden of disease. However, screening participation remains suboptimal. Social media and other mobile health (mHealth) technologies are increasingly being used for health promotion and behaviour change. This paper reports on the protocol for a systematic review exploring the effect of social media and other mHealth interventions on cancer screening participation and intention.

METHODS AND ANALYSIS

This protocol is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) checklist. We will include any randomised controlled trials or quasi-experimental studies with a pre/post design conducted in adults ≥18 years of age that report on the effectiveness of a social media or mHealth intervention on screening participation or intention (inclusive of breast, cervical, colorectal, prostate and lung cancer). Interventions will be inclusive of those delivered online or through a computer using an established social media platform or a new purpose-built platform, or those delivered through cellphones or other wireless technologies. Any comparator will be acceptable (control group, alternate intervention or pre/post design). We will search Medline, EMBASE, PsycINFO, Scopus, CINAHL, the Cochrane Central Register of Controlled Trials, and Communication and Mass Media Complete from 1 January 2000 to 31 May 2019. Two independent reviewers will screen titles, abstracts and full-text articles with conflicts resolved through discussion or by a third reviewer, as needed. The two reviewers will also independently complete risk of bias assessments for each included study. We will report on the characteristics of the studies, participants and interventions in descriptive narrative form and report the absolute and relative differences in screening and intention attributable to social media and mobile technology interventions.

ETHICS AND DISSEMINATION

As this is a systematic review, ethical approval for conduct of this study is not required. We will pursue publication of study results in a relevant peer-reviewed journal and report our findings according to the PRISMA checklist.

TRIAL REGISTRATION NUMBER

CRD42019139615.

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.

Colorectal cancer screening with faecal testing, sigmoidoscopy or colonoscopy: a systematic review and network meta-analysis

OBJECTIVE

Evaluate effectiveness, harms and burdens of faecal blood testing, sigmoidoscopy and colonoscopy screening for colorectal cancer over 15 years.

DESIGN

We performed an update of a Cochrane systematic review, and performed network meta-analysis comparing randomised trials evaluating colorectal cancer screening with guaiac faecal occult blood test (gFOBT) (annual, biennial), faecal immunochemical test (FIT) (annual, biennial), sigmoidoscopy (once-only) or colonoscopy (once-only) in a healthy population, aged 50-79 years. We conducted subgroup analysis on sex. Follow-up >5 years was required for analysis of colorectal cancer incidence and mortality.

RESULTS

12 randomised trials proved eligible. Compared with no-screening, we found high certainty evidence for sigmoidoscopy screening slightly reducing colorectal cancer incidence (relative risk (RR) 0.76; 95% confidence interval (CI 0.70 to 0.83) and mortality (RR 0.74; 95% CI 0.69 to 0.80), while gFOBT screening had little or no difference on colorectal cancer incidence, but slightly reduced colorectal cancer mortality (annual: RR 0.69; 95% CI 0.56 to 0.86, biennial: RR 0.88; 95% CI 0.82 to 0.93). No screening test reduced mortality nor incidence by more than six per 1000 screened over 15 years. Sigmoidoscopy had a greater effect in men, for both colorectal cancer incidence (women: RR 0.86; 95% CI 0.81 to 0.92, men: RR 0.75, 95% CI 0.71 to 0.79), and mortality (women: RR 0.85; 95% CI 0.71 to 0.96, men: RR 0.67; 95% CI 0.61 to 0.75) (moderate certainty).

CONCLUSIONS

In a 15-year perspective, sigmoidoscopy reduces colorectal cancer incidence, while sigmoidoscopy, annual and biennial gFOBT all reduce colorectal cancer mortality. Sigmoidoscopy may reduce colorectal cancer incidence and mortality more in men than in women.

PROSPERO REGISTRATION NUMBER

CRD42018093401.

Measurement without management: qualitative evaluation of a voluntary audit & feedback intervention for primary care teams

Background

The use of clinical performance feedback to support quality improvement (QI) activities is based on the sound rationale that measurement is necessary to improve quality of care. However, concerns persist about the reliability of this strategy, known as Audit and Feedback (A&F) to support QI. If successfully implemented, A&F should reflect an iterative, self-regulating QI process. Whether and how real-world A&F initiatives result in this type of feedback loop are scarcely reported. This study aimed to identify barriers or facilitators to implementation in a team-based primary care context.

Methods

Semi-structured interviews were conducted with key informants from team-based primary care practices in Ontario, Canada. At the time of data collection, practices could have received up to three iterations of the voluntary A&F initiative. Interviews explored whether, how, and why practices used the feedback to guide their QI activities. The Consolidated Framework for Implementation Research was used to code transcripts and the resulting frameworks were analyzed inductively to generate key themes.

Results

Twenty-five individuals representing 18 primary care teams participated in the study. Analysis of how the A&F intervention was used revealed that implementation reflected an incomplete feedback loop. Participation was facilitated by the reliance on an external resource to facilitate the practice audit. The frequency of feedback, concerns with data validity, the design of the feedback report, the resource requirements to participate, and the team relationship were all identified as barriers to implementation of A&F.

Conclusions

The implementation of a real-world, voluntary A&F initiative did not lead to desired QI activities despite substantial investments in performance measurement. In small primary care teams, it may take long periods of time to develop capacity for QI and future evaluations may reveal shifts in the implementation state of the initiative. Findings from the present study demonstrate that the potential mechanism of action of A&F may be deceptively clear; in practice, moving from measurement to action can be complex.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4226-7) contains supplementary material, which is available to authorized users.

Impact on immigrant screening adherence with introduction of a population-based colon screening program in Ontario, Canada

Introduction

The literature suggests that differential colorectal cancer (CRC) screening adherence exists between Canada’s immigrant and nonimmigrant populations. This study explores the impact of Ontario’s population screening program, ColonCancerCheck, on CRC screening uptake in immigrant and nonimmigrant population groups.

Methods

Data from 2005, 2007‐2008, and 2011‐2012 was obtained from the Canadian Community Health Survey, to represent the intervention periods (the time periods before, during, and after implementation of the ColonCancerCheck intervention). Multivariable logistic regression was used to examine the effect of immigration status on the risk of nonadherence to guideline‐recommended CRC screening, and an interaction analysis was performed to determine whether the screening differential between immigrant and nonimmigrant populations changed upon introduction of the ColonCancerCheck program.

Results

Recent and long‐term immigrants were both at increased risk of CRC screening nonadherence compared to the Canadian‐born population (OR 3.73 (CI 2.25‐6.18) and OR 1.24 (CI 1.13‐1.36), respectively). While not statistically significant, there was an attenuation of the risk of nonadherence to screening for recent immigrants compared with Canadian‐born individuals after the implementation of the ColonCancerCheck program.

Conclusions

This study provides evidence of a screening differential between immigrants and nonimmigrants, and suggests that the implementation of the ColonCancerCheck screening program in Ontario may have increased colon screening uptake amongst recent immigrants. Further studies are needed to address the factors leading to inequities in immigrant CRC screening adherence.

Higher plasma concentration of TP53-induced glycolysis and apoptosis regulator is associated with a lower risk of colorectal cancer metastasis

Purpose

We aimed to explore the association of plasma TP53-induced glycolysis and apoptosis regulator (TIGAR) level with colorectal cancer (CRC) metastasis.

Methods

A cross-sectional study of 126 CRC patients was conducted in Xiamen, China. Multivariable logistic regression was used to calculate adjusted OR and 95% CIs of plasma TIGAR concentration for CRC metastasis in different models with adjustment for potential confounders. Area under the curve (AUC) of receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value.

Results

CRC patients with metastasis showed significantly decreased plasma TIGAR concentration compared to their controls (1.97±0.64 vs 2.49±0.69 ng/mL [log transformed], P=0.002). Higher plasma TIGAR was significantly associated with the decreased risk of CRC metastasis, and the adjusted OR (95% CI) was 0.134 (0.027–0.676, P=0.015) for per SD increase in plasma TIGAR concentration, and the trend test for increasing tertiles showed a negative trend of plasma TIGAR on risk of CRC metastasis (P for trend test: 0.005). Pearson correlation coefficients of plasma TIGAR with other cancer biomarkers (carbohydrate antigen 50 [CA50], carbohydrate antigen 199 [CA199], carbohydrate antigen 125 [CA125], carbohydrate antigen 724 [CA724], carcinoembryonic antigen [CEA], and ferritin [FER]) was low (P>0.05). AUC (95% CI) of ROC curve of plasma TIGAR for CRC metastasis was comparable to the values of cancer biomarkers (all P-values <0.05).

Conclusion

Higher level of plasma TIGAR was significantly and independently associated with lower risk of CRC metastasis, and its prognostic value on CRC metastasis was comparable to the common cancer biomarkers.

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.

Screening for a new primary cancer in patients with existing metastatic cancer: a retrospective cohort study

BACKGROUND

Cancer screening aims to detect malignant disease early in its natural history when interventions might improve patient outcomes. Such benefits are unclear when screening occurs for patients with an existing high risk of death. Our aim was to study the extent of routine cancer screening for a new primary cancer in patients with existing metastatic cancer.

METHODS

We used administrative databases from Ontario to identify a retrospective cohort of adults of eligible screening age (≥ 50 yr) who had a diagnosis of stage IV (metastatic) colorectal, lung, breast or prostate cancer between 2007 and 2012. We calculated the cumulative incidence of cancer screening over time for colorectal and breast cancer.

RESULTS

Among the 20 992 patients with metastatic lung, breast or prostate cancer, 2.9%, 6.3% and 13.3% of patients, respectively, underwent testing for colorectal cancer within 1 year of cancer diagnosis. Within 3 years of diagnosis, rates reached 4.1%, 12.3% and 27.5%, respectively (8.5% of all patients). Incidence of colorectal cancer testing was higher among patients who received their diagnoses more recently compared with patients with diagnoses from earlier time periods (p = 0.0143). Among the 10 034 women with metastatic lung or colorectal cancer, 8.7% and 8.0% of patients, respectively, underwent breast cancer screening within 1 year of cancer diagnosis. Within 3 years of diagnosis, screening rates reached 10.2% and 13.1%, respectively.

INTERPRETATION

Our findings indicate excessive rates of cancer screening among patients with metastatic cancer who are unlikely to benefit. Further studies are warranted to identify predictors for screening, resource implications, potential and real harms borne by patients, and the impact of a recent Choosing Wisely statement recommending against the practice.