. Author manuscript; available in PMC: 2018 Oct 10.
Published in final edited form as:Ann Intern Med. 2017 Oct 10;167(8):565–575. doi:
10.7326/M17-1361 Abstract Background:Fecal immunochemical testing is the most commonly used method for colorectal cancer screening worldwide. However, its effectiveness is frequently undermined by failure to obtain follow-up colonoscopy after positive test results.
Purpose:To evaluate interventions to improve rates of follow-up colonoscopy for adults after a positive result on a fecal test (guaiac or immunochemical).
Data Sources:English-language studies from the Cochrane Central Register of Controlled Trials, PubMed, and Embase from database inception through June 2017.
Study Selection:Randomized and nonrandomized studies reporting an intervention for colonoscopy follow-up of asymptomatic adults with positive fecal test results.
Data Extraction:Two reviewers independently extracted data and ranked study quality; 3 rated overall strength of evidence for each category of study type.
Data Synthesis:Twenty-three studies were eligible for analysis, including 7 randomized and 16 nonrandomized studies. Three were at low risk of bias. Eleven studies described patient-level interventions (changes to invitation, provision of results or follow-up appointments, and patient navigators), 5 provider-level interventions (reminders or performance data), and 7 system-level interventions (automated referral, precolonoscopy telephone calls, patient registries, and quality improvement efforts). Moderate evidence supported patient navigators and provider reminders or performance data. Evidence for system-level interventions was low. Seventeen studies reported the proportion of test-positive patients who completed colonoscopy compared with a control population, with absolute differences of −7.4 percentage points (95% CI, −19 to 4.3 percentage points) to 25 percentage points (CI, 14 to 35 percentage points).
Limitation:More than half of studies were at high or very high risk of bias; heterogeneous study designs and characteristics precluded meta-analysis.
Conclusion:Patient navigators and the provision to providers of reminders or performance data may help improve colonoscopy rates of asymptomatic adults with positive fecal blood test results. Current evidence about useful system-level interventions is scant and insufficient.
TOC summaryFollow-up of asymptomatic adults with positive screening test results is sometimes poor. This systematic review of 23 studies details evidence about the effectiveness of patient-, provider-, and system-level inventions aimed at improving rates of follow-up colonoscopy after a positive result on a fecal test (guaiac or immunochemical).
Colorectal cancer (CRC), the second leading cause of cancer death in the United States (1), is largely preventable with screening (2). Annual or biennial testing for fecal occult blood with high-sensitivity guaiac or fecal immunochemical tests (fecal tests) has proven effectiveness based on randomized controlled trials (RCTs) (3) and is recommended for CRC screening in adults aged 50 to 75 years (4, 5). Fecal immunochemical testing has become the most commonly used method for CRC screening worldwide (5). It is also increasingly used in the United States to maximize population-level screening rates (6). However, the effectiveness of fecal screening tests depends on timely follow-up diagnostic colonoscopy of patients with positive test results; guidelines generally recommend colonoscopy within 1 to 3 months (5, 7, 8). A long interval between a positive test result and colonoscopy can have important implications for CRC prognosis (9–11).
The proportion of test-positive patients having a timely colonoscopy (for example, within 6 months) varies widely and can be lower than 50% (12, 13), compared with 80% to 90% in landmark RCTs (14, 15). Colonoscopy follow-up is complex because it involves the interaction of several levels of care and evaluating the appropriateness of an invasive diagnostic test (16, 17). Several patient-, provider-, and system-level factors have been evaluated to improve follow-up of test-positive patients (13, 18–21), but lack of comparative data impedes implementation of potentially effective interventions.
Previous reviews of interventions to improve follow-up of fecal tests either have not used a systematic search strategy, have not determined levels of evidence for intervention types, or are outdated (22, 23). Our aims were therefore to identify interventions that have been evaluated for improving rates of follow-up colonoscopy after positive fecal test results and to assess whether evidence supports these interventions.
MethodsOur protocol is registered in PROSPERO (CRD42016048286). In contrast to the analysis plan stated there, meta-analyses were not done because of study heterogeneity. Reporting conformed to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines (24).
Data Sources and SearchesWe searched the Cochrane Central Register of Controlled Trials, PubMed, and Embase without language restrictions from inception through 30 June 2017 (Appendix Table 1, available at Annals.org). Conference proceedings were included, and pertinent reference lists were manually searched. Both ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry were searched for unpublished studies, returning 2 relevant trials. We contacted the study investigators: 1 trial was never completed (25), and the other’s investigator did not respond (26).
Study SelectionTwo investigators (K.S. and C.B.) independently screened titles and abstracts. We included both randomized and nonrandomized studies that examined asymptomatic adults aged 41 years or older with a positive result on a fecal immunochemical test or fecal occult blood test (FOBT), that primarily used colonoscopy to evaluate those patients, and that reported an intervention focused on improving follow-up.
Two investigators then independently evaluated the full-text articles. Interventions covering more than 1 cancer type were included, but only the effect on fecal blood test follow-up was considered. Disagreements were resolved by consensus.
Data Extraction and Quality AssessmentTwo investigators extracted data, using as the primary outcome measure the absolute difference between the intervention and control groups in the proportion of patients with positive fecal test results who had completed a colonoscopy by 180 days after the test. We chose 180 days because more than 90% of follow-up colonoscopies occur within that interval and longer delays have clinical implications (11, 13). Other time periods were used if 180-day results were not available or the follow-up interval was not specified. Given that most patients had colonoscopy and colonoscopy is the examination of choice after a positive finding from a fecal test (27), all results were presented as the proportion of test-positive patients receiving a follow-up colonoscopy. When necessary, we contacted study authors to specify screening versus symptomatic patients and the absolute numbers of participants who had colonoscopy. One study was excluded because it included symptomatic patients (28), and another because the intervention was unclear without additional information (29). One author provided additional results not available in the report (30); 4 authors of included studies either did not respond or no longer had access to the study data set (31–35).
Two reviewers independently assigned each study a level for risk of bias (low, medium, high, or very high) for the absolute increase in colonoscopy completion (Appendix Table 2, available at Annals.org) (36, 37). Randomized controlled trials were considered to be at low risk of bias but were upgraded to moderate or high risk if they had flaws in recruitment, randomization, or follow-up. Observational or nonrandomized interventional studies were considered to be at high risk of bias and were downgraded to moderate risk if their design and measurement were particularly strong. Conversely, they were upgraded to very high risk if important flaws existed in their eligibility criteria, measurement, and loss to follow-up.
Data Synthesis and AnalysisPrimary investigations were organized by type of intervention (patient-, provider-, or system-level). We first used a descriptive approach to summarize study characteristics and outcomes for each category. A 10% absolute increase in colonoscopy completion was considered to be clinically important (9). Stata, version 14 (StataCorp), was used to calculate the absolute change in colonoscopy completion with CIs and P values when not available in included articles.
Two investigators (K.S. and J.L.) independently assigned overall strength-of-evidence ratings to each category using criteria from the Agency for Healthcare Research and Quality based on risk of bias, consistency, directness, and precision (36). Differences were resolved by consensus and input from a third reviewer (D.C.). Overall strength of evidence for each type of intervention was rated as high, moderate, or low on the basis of the level of confidence that the evidence reflected the true effect and the likelihood that future research will change the estimate.
Role of the Funding SourceThe National Cancer Institute funded this study through the PROSPR (Population-based Research Optimizing Screening through Personalized Regimens) consortium (U54 CA163262 [Dr. Corley]). The funding sources had no role in the design and conduct of the study; collection, management, analysis, or interpretation of the data; or preparation, review, or approval of the manuscript.
ResultsAfter removal of duplicate records, the search identified 7232 studies, of which we evaluated 77 full-text articles (Figure 1). A total of 23 reports containing 26 comparisons were retained, including 7 randomized and 16 nonrandomized studies. Figure 2 provides an overview of the 26 comparisons, organized by intervention level and category, and Table 1 gives details of study populations and interventions. Three studies had low risk of bias (Van Roosbroeck and colleagues [38], Green and colleagues [39], and Raich and colleagues [40]). The number of fecal test–positive patients ranged from 14 to 39 105; the number of patients included was not reported in 2 studies. Fourteen studies reported government funding, 2 corporate funding (38, 41), 1 funding from local volunteer organizations (42), and 9 did not specify any funding sources (7, 31, 32, 34, 43–46). Five studies investigated follow-up of fecal immunochemical tests (38, 43, 46–48) and 18 of guaiac-based FOBTs.
Figure 1.Flow chart of study selection for interventions to improve follow-up of positive fecal blood tests for colorectal cancer screening. CENTRAL = Cochrane Central Register of Controlled Trials.
Figure 2.Overview of included studies of interventions to improve follow-up of positive fecal blood tests for colorectal cancer screening, by intervention level and category. HR = hazard ratio; NA = not applicable; NR = not reported.
n/a: not available; UK: United Kingdom; USA: United States of America
*Studies with separate reporting of more than one comparison are listed as A, B, C with further details in Table 1
†Risk of bias for individual study according to Agency for Healthcare Research and Quality and GRADE criteria (36,37), details in Appendix B
‖Follow-up interval given only when specifically provided by authors, otherwise marked unspecified
#Adjusted absolute change, as reported by study authors
Table 1.Details of Study Population, Interventions, and Controls, by Intervention Level and Type
Study, Year (Reference) Details Patient-level interventions Changes to invitation strategy to screening Grazzini et al, 2000 (42) Regional screening program; ItalyThe proportions of test-positive patients who had follow-up colonoscopy with and without the intervention were available for 17 studies; the 6 remaining studies either had no control group or reported only coefficients of change in colonoscopy completion rates (31, 33–35, 45, 48). The 17 studies with control and intervention proportions reported absolute differences of −7.4 percentage points (95% CI, −19 to 4.3 percentage points) to 25 percentage points (CI, 14 to 35 percentage points). Reported follow-up intervals varied between 30 days and 1 year, although 12 studies did not specify a time interval. Given the heterogeneity in study interventions, study design, and whether usual care was used as a control group, no meta-analysis was done.
Patient-Level InterventionsThe 11 patient-level intervention studies used the following 3 general strategies: changes to the screening invitation strategy (38, 42), provision to patients of test results or follow-up appointments (33, 43, 45, 47), and patient navigator programs (31, 32, 39, 40, 48).
We included 2 studies focusing on changes made by organized programs to their invitation strategies to increase overall participation because they subsequently reported the proportion of patients with positive test results who had colonoscopy (38, 42). One of the studies was at low risk of bias and tested the effect of an invitation letter with a fecal immunochemical test included that could be returned by mail. Among 435 test-positive participants, similar proportions completed follow-up colonoscopy in the control and intervention groups (absolute difference, −1.9% [CI, −11% to 7.4%]) despite higher overall adherence to screening in the intervention group receiving the fecal test kit by mail (38). The second study showed that having primary care physicians sign an invitation letter increased not only FOBT completion but also colonoscopy follow-up of positive results. These 2 studies suggest that changes to programs’ invitation strategies to increase screening are not associated with important decreases in colonoscopy follow-up of patients with positive test results.
Four studies examined mailing or calling all patients to provide them with their test results or appointments to discuss follow-up colonoscopy, with a total of 6 between-group comparisons (33, 43, 45, 47). Mailing FOBT results to all participants in a systematic screening program and, if test results were positive, informing them of the need for colonoscopy increased colonoscopy completion rates by 16.1% (P = 0.04) (33). Two studies added systematic follow-up telephone calls to patients with positive results, compared with control groups receiving results only by mail (43, 47). In 1 of these, an RCT with moderate risk of bias, addition of a telephone call to the initial invitation did not significantly change follow-up (change, 2.0% [CI, −2.2% to 6.2%]). Among initial nonresponders, a reminder call from a specialized nurse did increase follow-up by 12% (CI, 0.5% to 24%), whereas a reminder from a generalist physician had a trend toward a decrease in follow-up (change, −7.4% [CI, −19% to 4.3%]). A final study mailed a second appointment time to test-positive patients who did not present for an initial appointment (45).
The 5 studies of patient navigation interventions included 2 randomized trials with low risk of bias (39, 40). The first compared usual care (a patient registry and electronic health record [EHR] reminders) with the addition of registered nurse patient navigators (39). The navigators helped with logistic barriers and used motivational interviewing, resulting in a non–statistically significant, but potentially clinically relevant, adjusted increase from 80.8% to 91.0% of patients completing colonoscopies (difference, 10.1% [CI, −1.5% to 22%]). The study was powered to detect a 15% difference, and the authors attributed the lack of a significant increase to the fact that the usual care group already had high-quality tracking of patients. The second study was an RCT of patient navigators for the follow-up of abnormal results on breast, colorectal, and prostate screening tests who maintained regular contact with participants until the completion of follow-up. It showed substantial improvements using a “strengths-based” approach to focus on participants’ assets and encourage action: 79% of patients in the intervention group had either colonoscopy or another definitive follow-up test, compared with 58% in the control group (difference, 21 percentage points [CI, 9.5 to 33 percentage points]) (40). However, this study included some patients with CRC symptoms and counted several possibilities of test resolution other than colonoscopy, making the results less comparable to those of other studies. The other 3 studies used similar navigators, who provided personalized contact and problem solving to patients, but were observational studies with high or very high risk of bias (31, 32, 48).
Provider-Level InterventionsAll 5 provider-level intervention studies used provider reminders or performance data (30, 35, 41, 49, 50). They used electronic algorithms to clearly identify ordering providers and remind those who had taken no initial action or inadequate action within 60 or 90 days of a positive fecal test result. Four of the studies came from integrated systems in the United States and showed statistically significant, positive results with absolute improvements in colonoscopy completion of 9 to 25 percentage points (30, 41, 49, 50). The fifth study used centrally generated reports from a provincial screening program and did not show any difference in colonoscopy rates (hazard ratio, 0.95 [CI, 0.79 to 1.13]) (35).
System-Level InterventionsThe 7 studies of system-level interventions used automated referral of patients with positive fecal test results to a gastroenterologist for colonoscopy scheduling (46, 51), replacing the precolonoscopy office visit with a telephone call (44), a registry to track patients with positive test results (52), or a multicomponent quality improvement effort (7, 34, 53).
The 2 studies of automated referral involved directly sending all positive fecal test results to gastroenterologists rather than awaiting manual referral from a primary care provider (46, 51). One of the automated referral studies was designed as a cluster randomized trial, but because few sites completed the trial, analyses were done using before-and-after comparisons at intervention sites (51). It showed improvements in the number of referrals and decreases in time to colonoscopy but only a 6.5% change (CI, −6.0% to 19%) in colonoscopy completion (51).
Only 1 study examined the replacement of in-person precolonoscopy visits with telephone calls (44), and another examined the implementation of a patient registry to track positive fecal test results (52); both were at high risk of bias. Three studies described the effect of quality improvement efforts in the Department of Veterans Affairs (VA) health care system using nonrandomized study designs (7, 34, 53). A multicomponent intervention showed large improvements in rates of referral to a gastroenterologist and decreases in time to colonoscopy but a 6.0% improvement (CI, 2.7% to 9.2%) in the principal outcome of meeting the VA target of colonoscopy completion within 60 days of a positive test result.
Overall Strength of EvidenceThe overall strength of evidence supporting the use of interventions from each category was evaluated using Agency for Healthcare Research and Quality criteria, with details provided in Table 2 (36). Two categories had moderate strength of evidence: patient navigators and the provision to providers of reminders or performance data. Patient navigator studies had moderate evidence because of 2 high-quality RCTs at low risk of bias with consistent positive trends in their results (39, 40). Although 1 did not achieve statistical significance (39), it was underpowered and its point estimate of a 10% improvement in follow-up reached our threshold for clinical importance. Moderate evidence for the provision to providers of reminders or performance data was based on consistent, direct evidence for increases in colonoscopy completion across 4 studies, although 1 recent study failed to show an effect (35). All other categories, including all categories of system-level interventions, had low strength of evidence due to various problems with risk of bias, inconsistent effects on colonoscopy rates, and imprecise estimates of the effect on colonoscopy rates.
Table 2.Strength-of-Evidence Grade, by Intervention Category*
Intervention Level and Type Risk of Bias of Included Studies† Consistency‡ Directness§ Precision‖ Overall Strength of Evidence¶ Patient-level interventions Changes to invitation strategy to screening (38, 42) 1 low, 1 high Inconsistent Direct Imprecise Low Provision to patients of test results or follow-up appointments (33, 43, 45, 47) 2 moderate, 1 high, 1 very high Inconsistent Direct Imprecise Low Patient navigator (31, 32, 39, 40, 48) 2 low, 1 high, 2 very high Consistent Direct Imprecise Moderate Provider-level interventions Provision of reminders and/or performance data to providers (30, 35, 41, 49, 50) 3 moderate, 2 high Consistent Direct Precise Moderate System-level interventions Automated referral to gastroenterologist (46, 51) 1 moderate, 1 high Consistent Direct Imprecise Low Replacement of precolonoscopy visit with telephone call (44) 1 high Unknown Direct Imprecise Low Registry to track patients with positive results (52) 1 high Unknown Direct Imprecise Low Multicomponent quality improvement efforts (7, 34, 53) 2 high, 1 moderate Consistent Indirect Imprecise Low DiscussionThis systematic review evaluated many interventions for increasing follow-up colonoscopy completion rates after positive fecal test results, including patient-, provider-, and system-level interventions. Most studies had at least moderate risk of bias, and moderate evidence supported only patient navigators and the provision to providers of reminders or performance data.
Our systematic review, which used a broad search strategy and included detailed critical appraisal, differs from other reviews we identified (22, 23). A narrative review without a specified search strategy of interventions to improve follow-up of abnormal findings in cancer screening from 2004 identified only 1 trial for FOBT (41) and 1 for sigmoidoscopies (22). A systematic review of Embase, MEDLINE, Cochrane Central Register of Controlled Trials, and Google Scholar from 2017 identified 13 studies, which we included in our review, but it did not include conference proceedings, had only 1 reviewer, and did not systematically evaluate risk of bias and levels of evidence (23). Similar to our findings, that review highlighted that “screening specialists to aid the patient journey,” or patient navigators, and “tracking and reminder systems” can “increase diagnostic testing” (23).
Timely diagnostic colonoscopy after a positive fecal test result is a critical step on the CRC screening continuum (16). Although research has primarily focused on screening completion (54, 55), fecal testing will not be effective if positive results are not followed up. The included studies reported changes in the proportion of test-positive patients receiving a follow-up colonoscopy between −7 and 23 percentage points (Figure 2). Modeling studies suggest that every 10% increase in follow-up colonoscopy after a positive fecal test result represents a clinically important increase of approximately 7 additional cancer cases detected per 1000 tests with positive results (9).
The finding of moderate evidence supporting patient navigators adds to strong evidence supporting their use for screening colonoscopy (55, 56) and for symptomatic patients with anemia or rectal bleeding (57, 58). Patient navigators can provide one-on-one education and individualized reduction of structural barriers. Cost may be a limiting factor, however: An economic evaluation concluded that patient navigation for the follow-up of abnormal results on cancer screening tests costs an additional $275 per patient (CI, $260 to $290) (59).
Two promising, low-cost interventions for integrated systems are implementing provider reminder systems in the EHR and directly notifying endoscopists of all positive fecal test results. Nearly all test-positive patients will require colonoscopy, and comprehensive EHRs can allow the automatic transfer of patient information. A recent study found an association between VA clinics using direct gastroenterology notification and higher rates of colonoscopy completion at 6 months (odds ratio, 1.25 [CI, 1.06 to 1.47]) (60). However, direct notification requires accountability and patient-tracking capabilities by gastroenterology offices (61).
We identified several areas for future research. Greater standardization in results reporting between studies (that is, colonoscopy completion at 6 months) is needed to facilitate the comparison of strategies. The promising results of several nonrandomized studies should be replicated in high-quality randomized trials, especially in categories without any RCTs to date. Novel strategies to be evaluated could include increasing colonoscopy capacity in health systems by gastroenterologists, surgeons, or nonphysician staff; incentives for gastroenterology practices to encourage patient tracking and high completion rates; better engaging patients with access to their own medical records and low-cost reminder systems; and stratifying patient populations to target more intensive interventions to appropriate patients. Although the relatively small number of positive test results at any 1 clinic may limit research, making trials difficult outside of large integrated health systems like the VA, the widespread use of EHRs should allow better measurement of the effect of future interventions.
Several potential limitations merit mention. First, the included studies used heterogeneous outcome measurements, reporting follow-up colonoscopy rates at various time intervals or sometimes not at all. Second, the performance of colonoscopy is a surrogate outcome; however, several trials using FOBT screening and high rates of colonoscopy follow-up of patients with positive test results have shown that this approach can decrease CRC mortality (3). Third, most U.S. studies (10 of 14) were done in the VA system, which has an integrated organization structure and more than 90% male patients, possibly limiting the generalizability of our findings. Fourth, we cannot rule out publication bias and may not have found all trials reporting on changes in colonoscopy follow-up with different invitation strategies (for example, mailed fecal tests) because our search strategies were not specifically tailored to capture these studies. Finally, most studies were at moderate, high, or very high risk of bias, meaning that the effects reported on follow-up colonoscopy rates may be substantially different in future studies. The inclusion of nonrandomized studies provides a fuller picture of research results but may be misleading and overstate confidence in our results.
In conclusion, our systematic review found 23 studies focused on improving rates of follow-up colonoscopy after positive fecal blood test results. Moderate evidence supports the implementation of patient navigators and the provision to providers of reminders or performance data; low-level evidence exists in other areas. More research is needed given the critical role of the diagnostic resolution of positive test results in fecal blood-based screening.
AcknowledgmentsGrant Support: The study was done through the National Cancer Institute–funded PROSPR (Population-based Research Optimizing Screening through Personalized Regimens) consortium (U54 CA163262 [Dr. Corley]). Dr. Selby received funding from the Swiss Cancer Research Foundation (BIL KFS-3720-08-2015). Dr. Baumgartner received funding from the Swiss National Science Foundation (P2BEP3_165409).
Primary Funding Source: National Cancer Institute. (PROSPERO: CRD42016048286)
Appendix Appendix Table 1.Search Strategies
Search strategy for MEDLINE PubMed (((((((“Colonoscopy”[Mesh] OR colonoscope OR colonoscopy OR sigmoidoscope OR sigmoidoscopy)) AND (((((“early detection of cancer”[MeSH Terms] OR “mass screening”[MeSH Terms] OR “early detection”OR screening) AND (“colorectal neoplasms”[MeSH Terms] OR colon cancer OR colonic cancer OR sigmoid cancer OR colorectal cancer* OR rectal cancer*)) OR (“stool test” OR “fecal immunochemical test” OR “faecal immunochemical test” OR “fecal occult blood test” OR “faecal occult blood test” OR FIT OR FOBT OR “Stool DNA”))) OR ((“Guaiac”[Mesh] OR “Occult Blood”[Mesh] OR immunochemistry[mh]) AND (“Feces”[Mesh] OR stool)))) AND (((“Lost to Follow-Up”[Mesh] OR “lost to follow up” OR timely OR “time factors” OR prompt OR “time factors”[mh] OR reminder OR “reminder systems”[mh] OR “reminder system” OR “reminder systems” OR “reminder” OR “reminders” OR “tickler” OR “followup” OR “follow up” OR “telephone call” OR “telephone calls”)))))) Search strategy for Ovid Embase 1. ‘colonoscope’/exp OR ‘colonoscope’ OR ‘colonoscopy’/exp OR ‘colonoscopy’ OR ‘sigmoidoscope’/exp OR ‘sigmoidoscope’ OR ‘sigmoidoscopy’/exp OR ‘sigmoidoscopy’ 2. ‘early detection of cancer’ OR ‘mass screening’ OR ‘early detection’ OR screening 3. ‘colorectal neoplasms’/exp OR ‘colorectal neoplasms’ OR ‘colon cancer’ OR ‘colonic cancer’ OR ‘sigmoid cancer’ OR ‘colorectal cancer*’ OR ‘rectal cancer*’ OR ‘stool test’ OR ‘fecal immunochemical test’ OR ‘faecal immunochemical test’ OR ‘fecal occult blood test’ OR fit OR fobt OR ‘stool dna’ 4. ‘guaiac’/exp OR ‘guaiac’ OR ‘occult blood’/exp OR ‘occult blood’ OR ‘immunochemistry’/exp OR ‘immunochemical’ 5. ‘feces’/exp OR ‘feces’ OR stool 6. #4 AND #5 7. #2 OR #3 OR #6 8. ‘follow up’/exp OR ‘lost to follow up’ OR timely OR ‘time factors’ OR prompt OR ‘time factor’ OR ‘reminder system’/exp OR ‘reminder system*’ OR reminder* OR tickler OR followup OR ‘follow up’ OR ‘telephone call*’ 9. #1 AND #7 AND #8 Search strategy for Cochrane Central Register of Controlled Trials Identification Search Hits #1 MeSH descriptor: [Colonoscopy] explode all trees 1815 #2 colonoscope or colonoscopy or sigmoidoscope or sigmoidoscopy 3654 #3 #1 or #2 3654 #4 MeSH descriptor: [Early Detection of Cancer] explode all trees 866 #5 MeSH descriptor: [Mass Screening] explode all trees 5504 #6 #4 or #5 or “early detection” or screening 27 634 #7 MeSH descriptor: [Colorectal Neoplasms] explode all trees 6124 #8 #7 or colon cancer or colonic cancer or sigmoid cancer or colorectal cancer* or rectal cancer* 12 956 #9 “stool test” or “fecal immunochemical test” or “faecal immunochemical test” or “fecal occult blood test” or “faecal occult blood test” or FIT or FOBT of “Stool DNA” 4989 #10 MeSH descriptor: [Guaiac] explode all trees 30 #11 MeSH descriptor: [Occult Blood] explode all trees 495 #12 #10 or #11 498 #13 MeSH descriptor: [Feces] explode all trees 2434 #14 #13 or stool 5550 #15 #12 and #14 85 #16 #8 or #9 or #15 17 471 #17 MeSH descriptor: [Follow-Up Studies] explode all trees 50 662 #18 MeSH descriptor: [Time Factors] explode all trees 57 027 #19 MeSH descriptor: [Reminder Systems] explode all trees 749 #20 #17 or “lost to follow up” or timely or “time factors” or prompt or #18 or reminder or #19 or “reminder system” or “reminder systems” or reminder or reminders or tickler or followup or “follow up” or “telephone call” or “telephone calls” 199 277 #21 #3 and #16 and #20 584 Appendix Table 2.Criteria Used for Determining Risk of Bias of Individual Studies*
Study Type Criteria Used Randomized controlled trial Considered to be at low risk of bias. Upgraded to moderate risk if there was concern for the following problems in the study design or reporting:Disclosures: Dr. Selby reports grants from the National Cancer Institute and the Swiss Cancer Research Foundation and funding from the Swiss National Science Foundation during the conduct of the study. Dr. Levin reports grants from the National Institutes of Health during the conduct of the study. Dr. Doubeni reports being a member of the U.S. Preventive Services Task Force during the conduct of the study and personal fees from UpToDate outside the submitted work. Dr. Jensen reports grants from the National Cancer Institute during the conduct of the study. Dr. Corley reports grants from the National Cancer Institute during the conduct of the study. Authors not named here have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M171361.
Reproducible Research Statement: Study protocol: PROSPERO (CRD42016048286). Statistical code: Not applicable. Data set: See the tables, figures, and appendix tables. Requests for Single Reprints: Kevin Selby, MD, Kaiser Permanente Division of Research, 2000 Broadway, Oakland, CA 94612; kevin.selby@hospvd.ch.
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