A 9-year follow-up study of participants and nonparticipants in sigmoidoscopy screening: importance of self-selection

Interval cancers in a population-based screening program for colorectal cancer with gender-specific cut-off levels for fecal immunochemical test

Objective

To evaluate interval cancers (IC) in the population-based Swedish regional colorectal cancer (CRC) screening program of Stockholm-Gotland, which uses gender-specific cut-off levels for the fecal immunochemical test (FIT).

Methods

All individuals aged 60–69 in Stockholm-Gotland invited to the screening program in October 2015 to September 2017 were followed up 2 years after invitation. Cut-off level for a positive FIT was 40 µg/g in women and 80 µg/g in men. Those with a positive FIT were referred to colonoscopy. Screening-detected CRC (SD-CRC) and IC after negative FIT (FIT-IC) or negative screening colonoscopy (Colonoscopy-IC) were identified in the Swedish colorectal cancer register. The IC rate was calculated as IC/(FIT negatives + negative screening colonoscopies). The IC incidence rate (ICs among negatives per 100,000 person-years) in different sex and age groups was compared to the mean CRC incidence before regional screening implementation. Test sensitivity was defined as SD-CRC/(SD-CRC + FIT-IC).

Results

Approximately 214,400 individuals were invited, and in 3521 screening colonoscopies 257(6.3%) SD-CRCs were detected. During follow-up, 124 FIT-IC and 7 Colonoscopy-IC were diagnosed, yielding an IC rate of 12.6 and 6.0 per 10,000 negatives (p = 0.00005) and a test sensitivity of 62% and 75% (p = 0.01) in men and women respectively. The IC incidence rate compared to CRC incidence was non-significantly lower in women.

Conclusion

In the population-based screening program of Stockholm-Gotland with a cut-off of 40 µg/g in women and 80 µg/g in men, the test sensitivity was higher and the IC rate was lower in women, which might imply lowering the cut-off level in men. However, the IC incidence rate relative to the CRC incidence was similar in both genders.

Colonoscopy Versus Fecal Immunochemical Test for Reducing Colorectal Cancer Risk: A Population-Based Case-Control Study

INTRODUCTION

Use of colonoscopy or the fecal immunochemical test (FIT) for colorectal cancer (CRC) prevention is supported by previous studies. However, there is little specific evidence regarding comparative effectiveness of colonoscopy or FIT for reducing CRC risk. In this study, we compared the association of CRC risk with colonoscopy and FIT using a nationwide database.

METHODS

This population-based case-control study used colonoscopy and FIT claims data from the Korean National Health Insurance System from 2002 to 2013. Data were analyzed from 61,221 patients with newly diagnosed CRC (case group) and 306,099 individuals without CRC (control group). Multivariable logistic regression models were used to evaluate the association between CRC and colonoscopy or FIT.

RESULTS

Colonoscopy was associated with a reduced subsequent CRC risk (adjusted odds ratio [OR] 0.29). Stronger associations were found between colonoscopy and distal CRC, compared with proximal CRC (0.24 vs 0.47). In an analysis stratified by sex, the association was weaker in female subjects compared with male subjects (0.33 vs 0.27). Any FIT exposure was associated with CRC risk with an OR of 0.74; this association was stronger for distal cancer. As the frequency of cumulative FIT assessments increased (from 1 to ≥5), the OR of FIT exposure for CRC gradually decreased from 0.81 to 0.45.

DISCUSSION

The association of colonoscopy or FIT with reduced CRC risk was stronger for distal CRC than for proximal CRC. FIT showed less CRC risk reduction than colonoscopy. However, as the frequency of cumulative FIT assessments increased, the association with CRC prevention became stronger.

Colonoscopic screening is associated with reduced Colorectal Cancer incidence and mortality: a systematic review and meta-analysis

It is the great priority to detect colorectal cancer (CRC) as early as possible, finally to reduce the incidence and mortality of CRC. However, although colonoscopy is recommended in many consensuses, yet no one systematic review is conducted to figure out how colonoscopy could change the incidence and mortality. In our study, we conducted a comprehensive meta-analysis to evaluate the association between colonoscopy screening and the incidence or mortality of CRC. PubMed, EMBASE, and PMC database were systematically searched from their inception to June 2020. A total of 13 cohort and 16 case-control studies comprising 4,713,778 individuals were obtained in this review. Our results showed that colonoscopy was associated with a 52% RR reduction in incidence of CRC (RR: 0.48, 95% CI: 0.46-0.49) and 62% RR reduction in mortality of CRC (RR: 0.38, 95% CI: 0.36-0.40). Subgroup analysis of different interventions, study design, country, sample size, age or sex showed that the incidence and mortality reduction remained consistent, and colonoscopy screening had the same effect on people below and above 50. Our study indicated that colonoscopy could significantly reduce the incidence and mortality of CRC.

Concurrent participation in screening for cervical, breast, and bowel cancer in England

Objectives

To determine how many women participate in all three recommended cancer screening programmes (breast, cervical, and bowel). During their early 60s, English women receive an invitation from all the three programmes.

Methods

For 3060 women aged 60–65 included in an England-wide breast screening case–control study, we investigated the number of screening programmes they participated in during the last invitation round. Additionally, using the Fingertips database curated by Public Health England, we explored area-level correlations between participation in the three cancer screening programmes and various population characteristics for all 7014 English general practices with complete data.

Results

Of the 3060 women, 1086 (35%) participated in all three programmes, 1142 (37%) in two, 526 (17%) in one, and 306 (10%) in none. Participation in all three did not appear to be a random event (p < 0.001). General practices from areas with less deprivation, with more patients who are carers or have chronic illnesses themselves, and with more patients satisfied with the provided service were significantly more likely to attain high coverage rates in all programmes.

Conclusions

Only a minority of English women is concurrently protected through all recommended cancer screening programmes. Future studies should consider why most women participate in some but not all recommended screening.

Ethical issues with colorectal cancer screening-a systematic review

RATIONALE, AIMS, AND OBJECTIVES

Colorectal cancer (CRC) screening is widely recommended and implemented. However, sometimes CRC screening is not implemented despite good evidence, and some types of CRC screening are implemented despite lack of evidence. The objective of this article is to expose and elucidate relevant ethical issues in the literature on CRC screening that are important for open and transparent deliberation on CRC screening.

METHODS

An axiological question-based method is used for exposing and elucidating ethical issues relevant in HTA. A literature search in MEDLINE, Embase, PsycINFO, PubMed Bioethics subset, ISI Web of Knowledge, Bioethics Literature Database (BELIT), Ethics in Medicine (ETHMED), SIBIL Base dati di bioetica, LEWI Bibliographic Database on Ethics in the Sciences and Humanities, and EUROETHICS identified 870 references of which 114 were found relevant according to title and abstract. The content of the included papers were subject to ethical analysis to highlight the ethical issues, concerns, and arguments.

RESULTS

A wide range of important ethical issues were identified. The main benefits are reduced relative CRC mortality rate, and potentially incidence rate, but there is no evidence of reduced absolute mortality rate. Potential harms are bleeding, perforation, false test results, overdetection, overdiagnosis, overtreatment (including unnecessary removal of polyps), and (rarely) death. Other important issues are related to autonomy and informed choice equity, justice, medicalization, and expanding disease.

CONCLUSION

A series of important ethical issues have been identified and need to be addressed in open and transparent deliberation on CRC screening.

Comparing the effectiveness of competing tests for reducing colorectal cancer mortality: a network meta-analysis

BACKGROUND

Comparative effectiveness data pertaining to competing colorectal cancer (CRC) screening tests do not exist but are necessary to guide clinical decision making and policy.

OBJECTIVE

To perform a comparative synthesis of clinical outcomes studies evaluating the effects of competing tests on CRC-related mortality.

DESIGN

Traditional and network meta-analyses. Two reviewers identified studies evaluating the effect of guaiac-based fecal occult blood testing (gFOBT), flexible sigmoidoscopy (FS), or colonoscopy on CRC-related mortality.

INTERVENTIONS

gFOBT, FS, colonoscopy.

MAIN OUTCOME MEASUREMENTS

Traditional meta-analysis was performed to produce pooled estimates of the effect of each modality on CRC mortality. Bayesian network meta-analysis (NMA) was performed to indirectly compare the effectiveness of screening modalities. Multiple sensitivity analyses were performed.

RESULTS

Traditional meta-analysis revealed that, compared with no intervention, colonoscopy reduced CRC-related mortality by 57% (relative risk [RR] 0.43; 95% confidence interval [CI], 0.33-0.58), whereas FS reduced CRC-related mortality by 40% (RR 0.60; 95% CI, 0.45-0.78), and gFOBT reduced CRC-related mortality by 18% (RR 0.82; 95% CI, 0.76-0.88). NMA demonstrated nonsignificant trends favoring colonoscopy over FS (RR 0.71; 95% CI, 0.45-1.11) and FS over gFOBT (RR 0.74; 95% CI, 0.51-1.09) for reducing CRC-related deaths. NMA-based simulations, however, revealed that colonoscopy has a 94% probability of being the most effective test for reducing CRC mortality and a 99% probability of being most effective when the analysis is restricted to screening studies.

LIMITATIONS

Randomized trials and observational studies were combined within the same analysis.

CONCLUSION

Clinical outcomes studies demonstrate that gFOBT, FS, and colonoscopy are all effective in reducing CRC-related mortality. Network meta-analysis suggests that colonoscopy is the most effective test.

Assessing generalizability of the findings of sigmoidoscopy screening trials: the case of SCORE trial

BACKGROUND

Several reports indicated that volunteers enrolled in preventive trials tend to show a different profile, with respect to sociodemographic characteristics, health-related behaviors, or medical history, compared with the source population. We conducted an incidence and mortality follow-up within a cohort of subjects who had been mailed a recruitment questionnaire in the SCORE trial of sigmoidoscopy (FS) screening for colorectal cancer (CRC) to assess the impact of self-selection in the study of volunteers willing to be screened on the outcomes estimates and on the generalizability of the results.

METHODS

We compared baseline demographics, CRC risk, and overall mortality at 11-year follow-up of responders declaring their interest in screening, with those of nonresponders and of responders not interested in screening using logistic regression and Cox proportional hazards multivariable models.

RESULTS

Both subjects who volunteered in the trial and those who refused were better educated than nonresponders. Men and people younger than age 60 years were more likely to volunteer among responders. At 11-year follow-up, interested responders showed a similar CRC risk as nonresponders, while CRC mortality was substantially reduced (hazard ratio [HR] = 0.70, 95% confidence interval [CI] = 0.54 to 0.91). All-cause mortality was reduced both among interested (HR = 0.61, 95% CI = 0.57 to 0.65) and uninterested responders (HR = 0.81, 95% CI = 0.76 to 0.86).

CONCLUSION

The implementation of an FS population-based screening program would result in a similar reduction in CRC incidence, as observed in the SCORE trial, and likely in a larger impact on CRC mortality.

Impact of sigmoidoscopy and colonoscopy on colorectal cancer incidence and mortality: an evidence-based review of published prospective and retrospective studies

Screening for colorectal cancer (CRC) using sigmoidoscopy or colonoscopy is now common in many developed countries. This concise, evidence-based review looks at the impact of sigmoidoscopy or colonoscopy screening on CRC incidence, CRC mortality and overall mortality. Data from controlled retrospective and prospective (observational or randomized) studies have generally shown that sigmoidoscopy and colonoscopy, whether for diagnostic, screening or surveillance purposes, are associated with a significant reduction in CRC incidence and CRC mortality. The data on their impact on overall mortality is much more limited, with most studies unable to report a reduction in overall mortality. The results of three meta-analyses have confirmed these conclusions. As expected, sigmoidoscopy has a predominant effect on left-sided CRC, although some studies have shown modest effects on right-sided colon cancer as well. Most studies on colonoscopy have demonstrated that the protective effect applies to both right and left-sided cancer, although the protection seemed better on the left side. Despite the introduction of other screening and diagnostic modalities for the colon, such as computed tomography colonography and colonic capsule endoscopy, lower endoscopy will continue to be an important mode of screening for CRC and evaluating the colon.

Effect of screening sigmoidoscopy and screening colonoscopy on colorectal cancer incidence and mortality: systematic review and meta-analysis of randomised controlled trials and observational studies

OBJECTIVES

To review, summarise, and compare the evidence for effectiveness of screening sigmoidoscopy and screening colonoscopy in the prevention of colorectal cancer occurrence and deaths.

DESIGN

Systematic review and meta-analysis of randomised controlled trials and observational studies.

DATA SOURCES

PubMed, Embase, and Web of Science. Two investigators independently extracted characteristics and results of identified studies and performed standardised quality ratings.

ELIGIBILITY CRITERIA

Randomised controlled trials and observational studies in English on the impact of screening sigmoidoscopy and screening colonoscopy on colorectal cancer incidence and mortality in the general population at average risk.

RESULTS

For screening sigmoidoscopy, four randomised controlled trials and 10 observational studies were identified that consistently found a major reduction in distal but not proximal colorectal cancer incidence and mortality. Summary estimates of reduction in distal colorectal cancer incidence and mortality were 31% (95% confidence intervals 26% to 37%) and 46% (33% to 57%) in intention to screen analysis, 42% (29% to 53%) and 61% (27% to 79%) in per protocol analysis of randomised controlled trials, and 64% (50% to 74%) and 66% (38% to 81%) in observational studies. For screening colonoscopy, evidence was restricted to six observational studies, the results of which suggest tentatively an even stronger reduction in distal colorectal cancer incidence and mortality, along with a significant reduction in mortality from cancer of the proximal colon. Indirect comparisons of results of observational studies on screening sigmoidoscopy and colonoscopy suggest a 40% to 60% lower risk of incident colorectal cancer and death from colorectal cancer after screening colonoscopy even though this incremental risk reduction was statistically significant for deaths from cancer of the proximal colon only.

CONCLUSIONS

Compelling and consistent evidence from randomised controlled trials and observational studies suggests that screening sigmoidoscopy and screening colonoscopy prevent most deaths from distal colorectal cancer. Observational studies suggest that colonoscopy compared with flexible sigmoidoscopy decreases mortality from cancer of the proximal colon. This added value should be examined in further research and weighed against the higher costs, discomfort, complication rates, capacities needed, and possible differences in compliance.

Ethical issues in colorectal cancer screening

In many countries, colorectal cancer screening is currently an established population screening program due to the evidence on its reduction of colorectal cancer mortality. There is general consensus that colorectal cancer screening meets the screening criteria as proposed by Wilson and Jungner. However, as for all population screening programs, colorectal cancer screening also has disadvantages and thereby entails ethical issues. There are the general issues concerning the introduction of screening programs (e.g. medicalization, overdiagnosis and overtreatment, information provision to screenees), evaluation of cancer screening programs (e.g. lead time and length bias), chosen screening method (e.g. false-positive and false-negative test results, reduction of all-cause mortality, choice between different screening methods). The different colorectal cancer screening methods and the ethical issues concerning colorectal cancer screening will be discussed in this review.

Reasons for non-participation in population-based abdominal aortic aneurysm screening

Background

A population-based screening programme for abdominal aortic aneurysm (AAA) started in 2010 in Stockholm County, Sweden. This present study used individual data from Sweden's extensive healthcare registries to identify the reasons for non-participation in the AAA screening programme.

Methods

All 65-year-old men in Stockholm are invited to screening for AAA; this study included all men invited from July 2010 to July 2012. Participants and non-participants were compared for socioeconomic factors, travel distance to the examination centre and healthcare use. The influence of these factors on participation was analysed using univariable and multivariable logistic regression models.

Results

The participation rate for AAA screening was 77·6 per cent (18 876 of 24 319 men invited). The prevalence of AAA (aortic diameter more than 2·9 cm) among participants was 1·4 per cent. The most important reasons for non-participation in the multivariable regression analyses were: recent immigration (within 5 years) (odds ratio (OR) 3·25, 95 per cent confidence interval 1·94 to 5·47), low income (OR 2·76, 2·46 to 3·10), marital status single or divorced (OR 2·23, 2·08 to 2·39), low level of education (OR 1·28, 1·16 to 1·40) and long travel distance (OR 1·23, 1·10 to 1·37). Non-participants had a higher incidence of stroke (4·5 versus 2·8 per cent; P &lt; 0·001) and chronic pulmonary disease (2·9 versus 1·3 per cent; P &lt; 0·001). Daily smoking was more common in residential areas where the participation rate for AAA screening was low.

Conclusion

Efforts to improve participation in AAA screening should target the groups with low income, a low level of education and immigrants. The higher morbidity in the non-participant group, together with a higher rate of smoking, make it probable that this group also has a high risk of AAA.

High rate of advanced adenoma detection in 4 rounds of colorectal cancer screening with the fecal immunochemical test

BACKGROUND & AIMS

Few data have been published on the performance of colorectal cancer (CRC) screens that use multiple rounds of the fecal immunochemical test (FIT). We evaluated outcomes of 4 screening rounds in over 7 years in an Italian population-based program.

METHODS

We conducted a prospective cohort study of 2959 average-risk subjects, aged 50-74 years, who were invited for the first screening round in 2001. We assessed the participation rate, the yield of advanced adenomas and CRC detected in the screening examinations, and we collected information about interval CRCs, with a follow-up period of 8.5 years.

RESULTS

Participation in each round varied from 56% to 63%; 48.1% of eligible subjects attended all 4 invitations. The positive predictive value of the FIT for advanced neoplasia (CRC or advanced adenoma) was 40% at the first round, and approximately 33% in the subsequent rounds. This decrease was attributable mainly to a decrease in the detection of CRC, although a high rate of advanced adenomas (range, 0.8%-1.7%) was observed over all rounds. To find one advanced neoplasia in the study period the number of people that needed to be screened was 28, and the number of tests needed was 74.

CONCLUSIONS

About 60% of invited individuals participated in every single round of FIT screening for CRC, but less than 50% attended all 4 tests. A high detection rate of advanced adenomas in all rounds indicates that FIT screening could have a higher impact on incidence of CRC than the guaiac fecal occult blood test.

Population based cancer screening programmes as a teachable moment for primary prevention interventions. A review of the literature

Background and aim: Unhealthy diet, physical inactivity, and smoking are key risk factors for the major non-communicable diseases such as cancer, cardiovascular diseases, and diabetes. The screening procedure may represent an ideal setting for promoting healthy lifestyles as it represents a time when subjects are probably more inclined to consider a relationship between their own habits and their effects on health. The aim of this study is to review available evidence concerning interventions combining screening and primary prevention interventions, aimed at promoting the adoption of healthy lifestyles. Methods: We searched the MEDLINE and Cochrane library electronic databases for intervention studies of primary prevention interventions implemented in the context of established screening programmes, or of pilot screening projects, where the study design included a comparison group. Results: Comprehensive interventions are acceptable for asymptomatic subjects targeted for cancer screening, can result in improvements and may be cost–effective. A positive impact of these interventions in favoring the adoption of cancer protective dietary behaviors was observed in all studies. Conflicting results were instead reported with respect to physical activity, while no impact could be observed for interventions aimed to favor smoking cessation. Conclusions: The retrieved studies suggest that the screening setting may offer valuable opportunities to provide credible, potentially persuasive life style advice, reaching a wide audience. A multiple risk factor approach may maximize the benefit of behavioral change, as the same health related habits are associated not only with cancers targeted by screening interventions, but also with other cancers, coronary artery disease, and other chronic conditions, while unhealthy behaviors may be mutually reinforcing. In order to cover a maximum number of possibilities, health education programmes should include multiple strategies, integrating and combining models of individual, social, and environmental change.

Acceptability and side-effects of colonoscopy and sigmoidoscopy in a screening setting

OBJECTIVE

Quantitative information on adverse reactions associated with colorectal cancer (CRC) screening tests is useful to estimate the balance between benefit and risk in different strategies.

SETTING

Six Italian screening centres.

METHODS

Thirty-day active follow-up (interview about side-effects and acceptability of the screening procedure and review of hospital admissions) among average-risk people undergoing flexible sigmoidoscopy (FS), total colonoscopy (TC), fecal immunochemical test (FIT) in a multicentre randomized trial of CRC screening. Multivariable logistic models were used to assess determinants of completion rate and self-reported pain.

RESULTS

The attendance rate following the first invitation and mail reminder was 28.2% (1696/6018) in the FS and 23.0% (1382/6021) in the TC arm. Response rate to the 30-day follow-up questionnaire was 88.6% (1502/1696) among people undergoing FS, and 86.7% (1198/1382) among those undergoing TC. The proportion of people complaining of serious reactions following bowel preparation (odds ratio [OR], 5.17; 95% confidence interval [CI] 3.70-7.24) or reporting severe pain immediately after the exam (OR, 1.86; 95% CI 1.47-2.34) was higher for TC than for FS. The most common post-procedural complaints were abdominal distension and pain. People mentioning pain or bowel distension following preparation were more likely to report severe pain both after FS (OR, 2.13; 95% CI 1.52-2.97) and TC (OR: 2.03; 95% CI 1.41-2.90). The 30-day hospitalization rate was similar after FS, TC and FIT.

CONCLUSIONS

Screenees reported higher pain levels after TC than FS. The proportion of people complaining of severe side effects after discharge was similar. Bowel preparation was poorly tolerated by people undergoing TC. Subjects' reactions to the bowel preparation was predictive of post-procedural discomfort. A commitment of at least 48 hours was required of people undergoing TC, compared with 3-4 for FS.

Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.

METHODS AND FINDINGS

Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59-0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing.

CONCLUSIONS

This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients.

Volunteer effect and compromised randomization in the Mayo Project of screening for lung cancer

It has been confirmed recently that the volunteer effect in lung cancer screening is characterized by higher lung cancer mortality risk in self-selected screening participants. The Mayo Lung Project, the most influential trial of screening for lung cancer ever completed, was conducted in nonvolunteer Mayo Clinic outpatients, with a peculiar study design that rendered the randomization vulnerable to the volunteer effect. Of all nonvolunteers randomized in the Mayo Lung Project, only those allocated in the screened group were asked consent to participate in the trial. The final Mayo Lung Project report stated that 655 randomized nonvolunteers refused screening and were excluded from the study, thus documenting violation of the rule that no selection should occur after randomization. The long-term follow-up of the Mayo Lung Project showed an enigmatic result which has never been explained: the lung cancer mortality was 13% higher in the screening intervention group than in the control group [4.4 (95% CI 3.9-4.9) vs. 3.9 (95% CI 3.5-4.4) per 1,000 person-years; P = 0.09]. Such overrepresented mortality is consistent with the volunteer effect and supports the concept that the Mayo Lung Project randomization was compromised by the post-randomization self-selection of participant nonvolunteers.