Su Young Kim and Min Seob Kwak contributed equally to this work as first authors.
These guideline is being co-published in
Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for the management of advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: (1) adenoma ≥10 mm in size; (2) 3 to 5 (or more) adenomas; (3) tubulovillous or villous adenoma; (4) adenoma containing high-grade dysplasia; (5) traditional serrated adenoma; (6) sessile serrated lesion (SSL) containing any grade of dysplasia; (7) serrated polyp of at least 10 mm in size; and (8) 3 to 5 (or more) SSLs. More studies are needed to fully comprehend the patients most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.
Colonoscopy is currently a key diagnostic modality for colorectal cancer (CRC) screening and the establishment of a treatment strategy. CRC remains one of the leading causes of cancer-related deaths worldwide, despite a decreasing trend in its incidence and mortality owing to the development of screening methods and prevention programs.
In Korea, fecal occult blood test has been adopted as an item of national cancer screening program for CRC. However, colonoscopy has already been considered for efficient test for CRC screening because of the characteristics of the healthcare environment in Korea, defined by its high accessibility and utility of health services, leading to a remarkable increase in the detection and resection of colorectal polyps.
The guidelines are applicable to all patients (both men and women, including those with comorbidities) who have undergone colonoscopy and had polyps removed. The Guidelines Development Committee and Taskforce Committee include gastroenterologists and methodological experts as members to develop a revised edition of existing guidelines (
The guidelines were developed based on the Guidance for the Development of Clinical Practice guidelines ver. 1.0, as published by the National Evidence-Based Healthcare Collaborating Agency (
The guideline development process consisted of three stages: planning, development, and finalization. The planning stage consisted of (1) selecting the key themes of the guidelines; (2) reviewing the existing guidelines; (3) establishing a development plan; and (4) selecting key questions. The development stage consisted of (5) searching for evidence, quality assessment, and synthesis; (6) writing recommendations and determining the strength of recommendation; and (7) drawing consensus. The finalization stage consisted of an external review and publication of the final guidelines.
The Task Force Committee, consisting of nine members, reviewed three guidelines developed in the United States (US Multi-Society Task Force [USMSTF]), Europe (European Society of Gastrointestinal Endoscopy [ESGE]), and the United Kingdom (UK) (British Society of Gastroenterology [BSG]). First, twelve related themes were selected. Detailed key questions were determined considering the patient population (P), intervention (I), comparator (C), and outcome (O). Thus, the key questions that represent the building blocks of the recommendations are presented as PICO questions (
The search for related literature was conducted by two taskforce members, using keyword terms for the guidelines. The major sources used for literature search included the international search engines PubMed, Ovid- Embase, and Cochrane libraries. A total of 503 guidelines published after 2015 were retrieved, after excluding duplicates. After reviewing titles and abstracts, 55 articles were selected. By reviewing the original texts of the articles, three guidelines that satisfied the following three conditions were finally selected: (1) guidelines including PICO that matched the key questions; (2) evidence-based guidelines that included the report of a systematic literature search and showed a clear connection between the recommendations and the supporting evidence; and (3) guidelines published in English (
Through a systematic literature review and inclusion/exclusion criteria, a quality assessment was conducted for the three guidelines published by USMSTF, ESGE, and BSG. All of them were selected as guidelines for adaptation (
The recommendations and related evidence of the three guidelines selected by the Task Force Committee were comprehensively reviewed to derive the primary recommendations for the key questions (
Here, the I2 value ranges between 0 and 100%. An I2 value <25% indicates large homogeneity, I2 of 25% to 50% indicates low heterogeneity, I2 of 50% to 70% indicates medium heterogeneity, and I2 ≥70% indicates high heterogeneity. The final strength of recommendation was determined by consensus of ≥80% of the members in principle, but was ultimately determined based on the consent of all members of the Taskforce Committee.
After drafting the statements, the drafts were sent to experts in the relevant field by e-mail for review in advance, and necessary modifications were made through teleconferencing. A modified Delphi technique was used for the revised statements to draw a consensus among multi-society and multi-institutional experts for final confirmation (
In this guideline, based on the Korean Guidelines for Postpolypectomy Colonoscopic Surveillance published in 2012, the most commonly used terms were defined as follows, after referring to domestic and foreign studies.
1) Postpolypectomy surveillance: Colonoscopic examination to detect synchronous and metachronous polyps for removal before turning malignant after polypectomy. This term excludes the use of colonoscopy or other examinations to monitor for recurrence after CRC treatment.
2) Advanced adenoma: Adenomas ≥10 mm in size with high-grade dysplasia/tubulovillous or villous adenoma.
3) Advanced neoplasia Advanced adenoma or CRC.
4) Serrated polyp: The umbrella term used to describe hyperplastic polyps, sessile serrated lesions (SSLs), and traditional serrated adenomas (TSA) based on pathological diagnostic criteria.
5) Index colonoscopy: Colonoscopy was performed most recently before the surveillance colonoscopy. Index colonoscopy refers to a high-quality examination performed with adequate bowel preparation by colonoscopists who have received supervised endoscopy training above a certain level.
6) Adequate bowel preparation: There is no consensus on the definition of adequate bowel preparation. The ESGE defines adequate bowel preparation as follows: Boston Bowel Preparation Scale ≥6, Ottawa Scale ≤7, or Aronchick Scale excellent, good, or fair.
7) High-quality examination: High-quality examination was defined based on various domestic and international guidelines and studies. Colonoscopy should be performed by a colonoscopist with an adequate adenoma detection rate (>30% for men, >20% for women). Patients undergoing colonoscopy should also undergo adequate bowel preparations. Colonoscopy should be performed up to the cecum, and the appropriate location (the entire cecum, ileocecal valve, and appendiceal orifice) should be determined. The examination is completed after observing the colonic mucosa during sufficient withdrawal time.
8) Index adenoma: An adenoma that serves as the most fundamental reference for colonoscopic surveillance. Among the adenomas found during index colonoscopy, the adenoma with the most advanced pathological findings is set as the index adenoma; however, if the pathological findings are the same, the index adenoma refers to the largest adenoma.
Most studies used as evidence in this guideline were performed in Western countries, and the number of studies on the Korean population was limited. Additionally, most foreign studies used evidence from observational studies rather than randomized controlled trials (RCTs), which limits the quality of evidence for this guideline. Therefore, the task force undertook a Delphi meeting with clinical experts in colorectal polyps treatment to reflect the clinical setting in Korea and to explore metrics for treating colorectal polyps in clinical practice.
An external review was conducted with experts from the Korean Society of Coloproctology who did not directly participate in developing this guideline to objectively verify the prepared draft. The outcomes of the external review can be found in the
The present guidelines will be published on the websites of relevant societies for viewing. Additionally, this guideline summarizes the latest trends and global evidence on postpolypectomy colonoscopic surveillance through systematic literature review and can be published in journals of relevant societies. The guidelines can also be used on various social media channels. To promote the implementation of the guidelines, a presentation in conference sessions is being considered, and changes in treatment patterns after releasing the guidelines will be monitored. We aim to monitor specific changes in treatment volume through open data sources, such as the Healthcare Big Data Hub (
All members who participated in developing the guidelines disclosed their real and explicit interests related to the development activities. None of the members, including the chairperson of the Guidelines Development Committee, had experience in the development or approval process of the guidelines under review before the development of the present guidelines, nor had any relationship with companies associated with medicines, commodities, and services related to the guidelines within the two years before developing the guidelines. Those who received research grants did not participate in the discussion or voting process when the medications of the relevant company were discussed. The authors received no financial support from institutions or organizations other than the Korean Society of Gastrointestinal Endoscopy, Korean Society of Gastroenterology, and Korean Association for the Study of Intestinal Diseases.
The guidelines assessed several risk factors to be reflected in determining the postpolypectomy surveillance interval and presented an appropriate surveillance interval based on the identified risk factors. The details of this summary are presented in
Similar to the 2012 domestic guidelines, a comprehensive review of studies reported since 2012 suggested that a large adenoma detected at index colonoscopy increased the future risk of advanced neoplasia development.
Based on the results of recent large cohort studies, Western guidelines state that 3 to 4 non-advanced adenomas (NAAs) do not increase the risk of metachronous advanced neoplasia, similar to 1 to 2 NAAs detected at index colonoscopy.
Therefore, a meta-analysis was performed on previous cohort studies that evaluated the risk of metachronous advanced neoplasia and CRC between groups with the removal of 3 or ≥5 NAAs and those with the removal of 1 to 2 NAAs without other high-risk findings at index colonoscopy. Among the included studies, there were differences in terms of patient eligibility criteria, number of surveillance attempts, and duration of follow-up. It was also difficult to determine the status of colonoscopy quality, use of high-definition endoscopy, and timing of surveillance. These studies also had different primary endpoints, making consistent comparisons and analyses challenging.
Although there was statistical heterogeneity in the included studies, a meta-analysis of studies that included patients with 1 to 2 NAAs (
When a meta-analysis was conducted with the incidence and RR of metachronous CRC, the incidence of CRC was 0.2%, 0.5%, and 0.1% in the 1 to 2 NAAs, ≥3 NAAs, and ≥5 NAAs groups, respectively (
In summary, there was no statistically significant difference in the RR of metachronous CRC in the ≥3 or ≥5 NAAs group compared to that in the 1 to 2 NAAs group at index colonoscopy; however, the RR of metachronous advanced neoplasia showed a significant increase. Although there was no statistical difference in the RR of metachronous CRC in the ≥5 NAAs group compared to the 3 to 4 NAAs group, the RR of metachronous advanced neoplasia showed an increasing statistical tendency. If studies on high-quality colonoscopy with high-definition endoscopy can be conducted and accumulated over time, meta-analyses should be performed to re-evaluate the risk of metachronous advanced neoplasia and CRC in the 3 to 4 NAAs group.
Physicians must be careful for patients aged <60 years with ≥10 colorectal adenomas, ≥60 years with ≥20 adenomas, or ≥10 adenomas with a family history of CRC or polyposis, since these have a risk of CRC above the average risk for hereditary CRC syndrome or serrated polyposis syndrome.
For histological classification of the adenomas, adenomas with <25% of villous components are classified as tubular adenomas, those with ≥75% of villous components are classified as villous adenomas, and those between the two ranges are classified as tubulovillous adenomas.
According to a large-scale study in Sweden that evaluated the risk of CRC in patients with colorectal polyps (
Although the 2013 ESGE guidelines included an adenoma with villous histology at index colonoscopy as a high-risk group for CRC incidence and mortality at long-term follow-up, based on several recent studies reporting that the risk of CRC was not high, an adenoma with villous histology was excluded from the high-risk group in the revised 2020 guidelines.
Similarly, in the UK, because of the low consistency among pathologists in its evaluation, villous histology has not been included in the BSG guidelines from a previous version, and it has been excluded from the definition of advanced adenoma.
To date, there have been no long-term prospective studies on mortality due to CRC and advanced neoplasia in patients with SSLs on index colonoscopy. Macaron et al.
TSA,
According to previous observational studies, a hyperplastic polyp detected on index colonoscopy does not increase the risk of CRC or advanced neoplasia. However, these studies are limited because the analyses were not performed according to the size and location of hyperplastic polyps.
TSAs are lesions with a risk of developing advanced neoplasia; however, there is a lack of supporting evidence. In a Danish cohort study comparing 2,045 patients with CRC and 8,105 controls, the number of patients with TSAs at baseline index colonoscopy was 14 (0.7%) and 17 (0.2%), respectively, and the adjusted OR was 4.84 (95% CI, 2.36–9.93).
In a nationwide population-based, nested case-control study in Denmark, the OR for future CRC incidence in SSL with dysplasia was approximately 5-fold compared to the cases without polyps (OR, 4.76; 95% CI, 2.59–8.73); the estimated 10-year risk of CRC was 4.43% for patients with SSL with dysplasia, which was higher than the 0.93% in the group without polyps. However, in addition to being a case-control study, another limitation is that, since this study was conducted based on pathological findings only, it was not confirmed whether the polyps detected at baseline index colonoscopy were completely removed.
In another prospective cohort study, patients with SSLs with dysplasia at baseline index colonoscopy showed a 9-fold higher incidence of metachronous conventional adenomas compared to controls (RR, 9.03; 95% CI, 1.03–16.03); however, there was no significant increase in the development of advanced adenoma (RR, 1.00; 95% CI, 0.15–4.32).
In another retrospective cohort study, high-risk SSLs (SSLs ≥10 mm in size or SSLs with dysplasia) did not correlate with advanced neoplasia at follow-up colonoscopy (HR, 0.57; 95% CI, 0.14–2.30).
To summarize, there is insufficient evidence to determine whether SSLs with dysplasia increase the risk of advanced adenoma and CRC incidence at follow-up colonoscopy. However, SSLs with dysplasia have more histological features consistent with CRC than those without dysplasia. Therefore, we recommend that SSLs with dysplasia be considered high-risk until more evidence is gathered, and these patients undergo repeat colonoscopy within 3 years. Similarly, the USMSTF, ESGE, and BSG guidelines published in 2020 recommended a 3-year surveillance colonoscopy for patients with SSLs with dysplasia.
According to a population-based RCT (
To date, there has been insufficient evidence to clarify whether the risk of developing CRC or advanced neoplasia increases when serrated polyps are removed during index colonoscopy. Recent guidelines state that re-discussion is required on this matter after more research evidence has been gathered.
Piecemeal resection of colorectal polyps has a higher rate of incomplete resection than
In cases of piecemeal resection, the degree of recurrence varies depending on the characteristics of the resected lesions and procedure. Tate et al.
Based on these studies, most foreign guidelines recommend a short interval of repeat colonoscopy in cases of piecemeal resection of colorectal polyps ≥20 mm. The 2020 USMSTF guidelines recommend that in cases of piecemeal resection of adenomas ≥20 mm or SSLs ≥20 mm, the first colonoscopic surveillance should be conducted within 6 months, the second surveillance should be conducted 1 year after the first, and the third surveillance should be conducted 3 years after the second.
Several studies have been performed to determine the effect of a family history of CRC on the incidence of advanced adenoma or CRC incidence. In 2015, Jang et al.
To summarize, most studies that analyzed the relationship between the family history of CRC and risk of developing advanced adenoma or CRC in colonoscopic surveillance after polyp removal did not present a high level of evidence of the correlation, and no statistically significant correlation was observed. Moreover, as most studies either excluded patients with hereditary CRC, such as familial adenomatous polyposis and hereditary non-polyposis CRC (Lynch syndrome), or were not sufficiently large to include these patients, we hereby specify that this statement is not a recommendation for patients with hereditary CRC. If there is a family history of CRC and related tumors, the possibility of hereditary CRC should be carefully examined and a colonoscopic surveillance plan should be established accordingly.
In the 2012 Korean guidelines, following a systematic literature search and meta-analysis, an increased risk of developing advanced neoplasia was considered when at least one of the following findings was observed at index colonoscopy after polypectomy, and the cases were defined as having a high-risk finding: ≥3 adenomas, adenomas ≥10 mm in size, tubulovillous or villous adenoma, adenoma with high-grade dysplasia, and serrated polyp ≥10 mm in size.
In many cohort studies conducted since 2012, the risk of CRC incidence and mortality in cases of adenomas without high-risk findings after polypectomy was similar to the normal findings at index colonoscopy.
Individuals without CRC-related high-risk findings after polypectomy are deemed to have the same risk level as that of the normal group in terms of CRC incidence, suggesting that the same colonoscopic surveillance interval could be set for the normal group. Considering that the main purpose of colonoscopic surveillance is to reduce CRC incidence and mortality, this point should be considered a clear guideline. A colonoscopic surveillance interval of 10 years is generally recommended for the normal group.
In cases of CRC-related high-risk findings after polypectomy at index colonoscopy, the colonoscopic surveillance interval should be shortened, and such high-risk findings can be determined based on the size, number, and histological findings of the resected polyps. In this guideline, the colonoscopic surveillance interval is presented in
In a large-scale prospective US cohort study with 15,935 patients detected with polyps at index colonoscopy, the risk of CRC incidence in patients with advanced neoplasia was 13% higher than in those without.
Most high-quality studies related to the risk factors for advanced neoplasia incidence are follow-up studies conducted with a cohort of participants in polyp prevention trials. These studies were conducted after the National Polyp Study, and surveillance was performed after index colonoscopy. In these studies, the risk of advanced adenoma increased in the high-risk group in surveillance conducted 3 years after index colonoscopy; however, the actual CRC incidence was rare. Thus, based on the evidence, adequate timing of surveillance for the high-risk group may be recommended as 3 years. Recent studies have compared the colonoscopic surveillance interval of 3 years to intervals within 3 years. In the case of surveillance interval of 3 years, although the incidence of advanced adenoma was high (OR, 2.02; 95% CI, 1.19–3.42), there was no significant difference in terms of CRC incidence and mortality; thus, the appropriate colonoscopic surveillance interval for high-risk groups may be recommended as 3 years.
Another point to consider is that when the examination of patients shows two or more findings among the findings corresponding to the high-risk group that increases the risk of detection of CRC or advanced neoplasia in postpolypectomy colonoscopic surveillance, a few studies have examined whether such cases with multiple findings increase the level of risk. According to a study by Atkin et al.
Patients with removed colorectal polyps have an increased risk of developing colorectal polyps or neoplasia in the future; therefore, management based on appropriate colonoscopic surveillance is required.
Adequate bowel preparation and high-quality examination are among the most important factors in establishing an appropriate interval for colonoscopic surveillance. Therefore, in the case of this guideline, unlike previous guidelines, the definitions of adequate bowel preparation and high-quality examination were specified in detail in the guideline development process. In cases of inadequate examination during index colonoscopy, subsequent colonoscopic surveillance may be needed to complement the initial inadequate examination, which is a significant limitation. According to a large cohort study, an inadequate level of colonoscopy examination at baseline increased the risk of CRC incidence and mortality after polypectomy, regardless of colonoscopic surveillance.
According to the present guidelines, the risk of advanced neoplasia and CRC incidence increased during colonoscopy surveillance when the number of adenomas at index colonoscopy was 3 to 5 or more. This was confirmed based on the meta-analysis reviewed when preparing the present guidelines as well as the recently revised USMSTF guidelines. As discussed previously, according to the meta-analysis, there was a statistically significant increase in the RR of developing advanced neoplasia in the group that had 3 to 5 or more adenomas removed compared to the group with 1 to 2 adenomas removed. Furthermore, the RR of CRC incidence increased with the number of adenomas, although the increase was not statistically significant. Therefore, in terms of determining the risk of future CRC and advanced neoplasia for evaluating the present guidelines, it was determined that there was a risk of 3 to 5 adenomas or more. The USMSTF guidelines also recommend colonoscopic surveillance 3 to 5 years after the development of ≥3 adenomas, although the surveillance interval is slightly longer than in previous guidelines.
A serrated polyp in the colon is an umbrella term used to describe hyperplastic polyps, SSLs, and TSA based on pathological diagnostic criteria.
This revised edition of the Korean guidelines contains new additions compared to previous guidelines as well as parts that are not specifically stated, as in the case of previous guidelines. Piecemeal resection of colorectal polyps is a new addition to this revision. The guidelines published in 2012 had no recommendation on the colonoscopic surveillance interval for piecemeal resection of colorectal polyps.
The age at which postpolypectomy colonoscopic surveillance is stopped differs slightly depending on the guidelines; in most cases, the recommended age is 75 to 80 years.
This guideline is a revision of the guidelines published in 2012, and is the second version in Korea. Although some studies on postpolypectomy colonoscopic surveillance have been conducted in Korea since 2012, available data are still limited. In Western countries, the healthcare environment is fundamentally different from that of Korea; in particular, there are considerable differences in terms of examination cost and access to colonoscopy. Guidelines greatly influence the clinical practice of physicians, and the scope of the influence is not limited to individual physicians, but affects the entire country beyond local communities. Therefore, for the Korean guidelines, the utility of medical resources should be considered in the future, and a cost-effectiveness analysis should be performed as a starting point. A cost-effectiveness analysis should be conducted based on research data in Korea, in accordance with the domestic healthcare environment, and if necessary, a comparative analysis with other countries should be conducted. The present guidelines are expected to help physicians to select more efficient and optimal methods for treating patients in real-world clinical settings. The last point to mention is that since there is a practical limitation to making decisions based only on guidelines considering clinical information of individual patients and various situations, the clinical judgment of individual physicians about the surveillance method and timing derived by synthesizing the guidelines and using various clinical data is thought to be the most important.
Appendix 1. Contributors to the guidelines development.
Appendix 2. Methodology.
Appendix 3. Search and selection of guidelines.
Appendix 4. Schema illustrating the flow of the search and selection of literature for development of the guidelines for post-polypectomy colonoscopic surveillance.
Appendix 5. Appraisal.
Appendix 6. Selected guidelines.
Appendix 7. Outline of evidence for recommendations.
Appendix 8. Evaluation of acceptability and applicability.
Appendix 9. Flowchart of literature selection process.
Appendix 10. The outcomes of the external review.
Appendix related to this article can be found online at
Supplementary Fig. 1. The incidence and relative risk of metachronous colorectal advanced neoplasia in the meta-analysis.
Supplementary Fig. 2. The incidence and relative risk of metachronous colorectal cancer in the meta-analysis.
Supplementary Table 1. The incidence of metachronous advanced neoplasia according to the number of non-advanced colorectal adenoma.
Supplementary Table 2. The relative risk of metachronous advanced neoplasia according to the number of non-advanced colorectal adenoma.
Supplementary materials related to this article can be found online at
Seon-Young Park is currently serving on the KSGE Publication Committee; however, she was not involved in the peer reviewer selection, evaluation, or decision process of this article. The remaining authors have no potential conflicts of interest.
Any costs for literature searches, conferences, and other statistical activities were covered by a research fund provided by the Korean Society of Gastrointestinal Endoscopy (KSGE). The KSGE supported the development of these guidelines. However, this organization did not influence the content of the guidelines.
We would like to express our gratitude to Chang Kyun Lee, Dong Il Park, Jae Myung Cha, Young-Eun Joo, Hyun-Soo Kim, Dong Soo Han, Dong-Kyung Chang, and Tae Il Kim, who provided invaluable advice for the development of the
Conceptualization: SYK, MSK; Data curation: MSK; Formal analysis: all authors; Investigation: SYK, MSK, SMY, YJ, JWK, SJB, EHO, SRJ, SJN, SYP, SKP, JC, DHB, MYC, SP, JSB; Methodology: MSK, MYC, SP; Project administration: JSB, HKK, JYC, MSL, OYL; Resources: SYK, MSK, SMY, YJ, JWK, SJB, EHO, SRJ, SJN, SYP, SKP, JC, DHB; Supervision: JSB, OYL; Validation: JSB, OYL; Visualization: SYK, MSK, SMY, YJ, JWK, SJB, EHO, SRJ, SJN, SYP, SKP, JC, DHB, JSB, HKK, JYC, MSL, OYL; Writing–original draft: SYK, MSK, SMY, YJ, JWK, SJB, EHO, SRJ, SJN, SYP, SKP, JC, DHB; Writing–review & editing: all authors.
Recommendations for postpolypectomy colonoscopic surveillance.
Definition of level of evidence
Level of evidence | Definition |
---|---|
High | ᛫ Study design: |
Intervention: The results are derived from randomized controlled trials (RCTs) or observational studies with control groups. | |
Diagnosis: Diagnostic accuracy studies in the form of RCTs or cross-sectional cohort studies | |
᛫ Considerations: There are no methodological concerns in terms of quality assessment of the evidence, and the evidence shows consistency with a sufficient level of precision; thus, the reliability of the synthesized results is considered high. | |
Moderate | ᛫ Study design: |
Intervention: The results are derived from RCTs or observational studies with control groups. | |
Diagnosis: Diagnostic accuracy studies in the form of RCTs or cross-sectional cohort studies | |
᛫ Considerations: There are slight concerns regarding the quality assessment, consistency, or precision of the evidence; thus, the reliability of the synthesized result is considered moderate. | |
Low | ᛫ Study design: |
Intervention: Results are derived from observational studies with or without controls/comparators. | |
Diagnosis: Diagnostic accuracy studies with a case-control design | |
᛫ Considerations: | |
There are serious concerns regarding the quality assessment, consistency, or precision of the evidence; thus, the reliability of the synthesized result is considered low. | |
Very low | ᛫ Study design: |
Intervention: Observational studies without controls/comparators or studies consisting of evidence-based on expert opinions or reviews | |
Diagnosis: Diagnostic accuracy studies with a case-control design | |
᛫ Considerations: There are critical concerns regarding the quality assessment, consistency, or precision of the evidence; thus, the reliability of the synthesized result is considered very low. |
Definition of strength of recommendation
Symbol | Strength of recommendation | Description |
---|---|---|
A | Strong recommendation | Considering the benefits and harms, level of evidence, values and preferences, as well as resources of the intervention/examination, it is strongly recommended in most clinical situations. |
B | Conditional recommendation | Considering that the use of the intervention/examination may vary depending on the clinical situation or values of the patient/society, selective use or conditional selection of the intervention/examination is recommended. |
C | Not recommended | The harm of the intervention/examination may outweigh the benefits, and considering the clinical situations or values of the patients/society, the use of the intervention/examination is not recommended. |
I | Inconclusive | Considering the benefit and harm, level of evidence, values and preferences, as well as resources required for the intervention/examination, the level of evidence is too low, the weighing of the benefit/harm is seriously indecisive, or the variability is large. Therefore, the use of the intervention/examination is not determined. |
Key questions addressed in this study
Summary and strength of recommendations for postpolypectomy colonoscopic surveillance
Index colonoscopy finding | Interval of colonoscopic surveillance | Strength of recommendation | Level of evidence |
---|---|---|---|
Adenoma ≥10 mm in size | 3 yr | Conditional recommendation | Low |
3–4 adenomasa) | 3–5 yr | Conditional recommendation | Moderate |
5–10 adenomasa) | 3 yr | Conditional recommendation | Moderate |
Number of adenomas >10 |
1 yr | Conditional recommendation | Moderate |
Tubulovillous adenoma or villous adenoma | 3 yr | Strong recommendation | Low |
Adenoma with high-grade dysplasia | 3 yr | Strong recommendation | Moderate |
Traditional serrated adenoma | 3 yr | Conditional recommendation | Low |
Sessile serrated lesion with dysplasia | 3 yr | Conditional recommendation | Very low |
Serrated polyp ≥10 mm | 3 yr | Conditional recommendation | Very low |
No. of sessile serrated lesions between 3–4 |
3–5 yr | Conditional recommendation | Very low |
No. of sessile serrated lesions ≥5 |
3 yr | Conditional recommendation | Very low |
Piecemeal resection of colorectal polyps ≥20 mm in size | 6 mo | Strong recommendation | Low |
Only applicable when there are no other high-risk findings (≥10 mm in size; high-grade dysplasia, tubulovillous adenoma, or villous adenoma).
Only applicable when there are no other high-risk findings (≥10 mm in size, dysplasia).