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It is estimated that there are about 1.4 million patients with colorectal cancer (CRC) worldwide, with a rising trend in CRC incidence in many Asian Pacific countries. In Hong Kong, colorectal cancer ranks first in cancer incidence and second in cancer mortality based on data from 2013.
CRC is one of the most preventable cancers because its development in general follows an adenoma-carcinoma sequence. Adenomas are considered precursor lesions for CRC.
While early detection and removal of colorectal adenoma by screening colonoscopy with polypectomy reduce CRC incidence and mortality, interval cancers (cancers that develop after a colonoscopy and before the next scheduled colonoscopy) may still occur and were reported to account for up to 10.5% of CRC. The protective effect of colonoscopy against cancer in the right colon has not been consistently demonstrated. Interval CRC has been associated with proximal colon location, small lesion, flat lesion, missed lesion, inadequate examination, incomplete resection of lesion, tumor biology, and low adenoma detection rate (ADR).
High ADR (eg, ≥ 20%) has been associated with a reduced risk of interval CRC. Methods that can improve polyp detection in the right colon such as retroflexed examination of the right colon, second forward view examination of the right colon, use of colonic fold flattening device, colonoscope with an increased field of view may potentially reduce the risk of interval CRC, but data is still limited. Performance of a second forward view (SFV) examination of the right colon may be the easiest and safest from a practical standpoint when compared to other options (eg, additional training is often needed for retroflexed examination of the right colon since there may be a potentially higher risk of perforation in endoscopists not familiar with the technique, additional equipment is needed when using a colonic fold flattening device, or a colonoscope with an increased field of view).
Our current study aims to determine whether a routine SFV examination in the right colon can lead to an increase in adenoma / polyp detection when compared to conventional withdrawal examination in the right colon in both male and female patients undergoing screening and surveillance colonoscopies.
It is estimated that there are about 1.4 million patients with colorectal cancer (CRC) worldwide, with a rising trend in CRC incidence in many Asian Pacific countries. In Hong Kong, colorectal cancer ranks first in cancer incidence and second in cancer mortality based on data from 2013.
CRC is one of the most preventable cancers because its development in general follows an adenoma-carcinoma sequence. Adenomas are considered precursor lesions for CRC.
While early detection and removal of colorectal adenoma by screening colonoscopy with polypectomy reduce CRC incidence and mortality, interval cancers (cancers that develop after a colonoscopy and before the next scheduled colonoscopy) may still occur and were reported to account for up to 10.5% of CRC. The protective effect of colonoscopy against cancer in the right colon has not been consistently demonstrated. Interval CRC has been associated with proximal colon location, small lesion, flat lesion, missed lesion, inadequate examination, incomplete resection of lesion, tumor biology, and low adenoma detection rate (ADR).
High ADR (eg, ≥ 20%) has been associated with a reduced risk of interval CRC. Methods that can improve polyp detection in the right colon such as retroflexed examination of the right colon, second forward view examination of the right colon, use of colonic fold flattening device, colonoscope with an increased field of view may potentially reduce the risk of interval CRC, but data is still limited. Performance of a second forward view (SFV) examination of the right colon may be the easiest and safest from a practical standpoint when compared to other options (eg, additional training is often needed for retroflexed examination of the right colon since there may be a potentially higher risk of perforation in endoscopists not familiar with the technique, additional equipment is needed when using a colonic fold flattening device, or a colonoscope with an increased field of view).
Our current study aims to determine whether a routine SFV examination in the right colon can lead to an increase in adenoma / polyp detection when compared to conventional withdrawal examination in the right colon in both male and female patients undergoing screening and surveillance colonoscopies.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Second forward view exam | Active Comparator | During withdrawal, the colonoscope will be advanced to the cecum again when hepatic flexure was reached the first time, where a second forward view (SFV) examination of the right colon will be performed. |
|
| Conventional withdrawal exam | No Intervention | No intervention additional to the conventional withdrawal examination during withdrawal |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Second forward view (SFV) examination of the right colon | Diagnostic Test | The colonoscope will be advanced to the cecum again when hepatic flexure was reached the first time, where a second forward view (SFV) examination of the right colon will be performed |
| Measure | Description | Time Frame |
|---|---|---|
| Per-patient ADR in the right colon in each group. | For the SFV group, it is defined as the number of patients with at least 1 adenoma identified in the right colon on either the first or second examination of the right colon divided by the total number of patients in the SFV group. Thus, if a patient has at least 1 adenoma detected on both the first examination and the second examination of the right colon, then this patient will be counted once only. For the conventional group, it is defined as the number of patients with at least 1 adenoma identified in the right colon on the conventional withdrawal examination of the right colon divided by the total number of patients in the conventional withdrawal group. | 24 months |
| Measure | Description | Time Frame |
|---|---|---|
| Increase in per-patient ADR in the right colon in the SFV group. | It is defined as the difference between the new ADR in the right colon after the first examination and SFV (again, if a patient has at least 1 adenoma detected on both the first examination and the second examination of the right colon, then this patient will be counted once only) and the ADR in the right colon after the first examination. |
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Inclusion Criteria
Exclusion Criteria
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| Name | Affiliation | Role |
|---|---|---|
| Raymond Tang, MD | Institute of Digestive Disease, The Chinese University of Hong Kong | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Prince of Wales Hospital, The Chinese University of Hong Kong | Shatin | New Territories | Hong Kong | |||
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 33065307 | Derived | Tang RSY, Lee JWJ, Chang LC, Ong DEH, Chiu HM, Matsuda T, Kim HS, Sekiguchi M, Leong RW, Ho AMY, Lam TYT, Tse YK, Lin L, Yeoh KG, Lau JYW, Sung JJY; Asia Pacific Working Group on Colorectal Cancer Screening. Two vs One Forward View Examination of Right Colon on Adenoma Detection: An International Multicenter Randomized Trial. Clin Gastroenterol Hepatol. 2022 Feb;20(2):372-380.e2. doi: 10.1016/j.cgh.2020.10.014. Epub 2020 Oct 14. |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Jul 27, 2018 | Jan 27, 2021 | Prot_SAP_000.pdf |
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| ID | Term |
|---|---|
| D003111 | Colonic Polyps |
| D015179 | Colorectal Neoplasms |
| ID | Term |
|---|---|
| D007417 | Intestinal Polyps |
| D011127 | Polyps |
| D020763 | Pathological Conditions, Anatomical |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| 24 months |
| Overall ADR for the entire colon in each group. | For the SFV group, it is defined as the number of patients with at least 1 adenoma identified on either the second examination of the right colon or on the first examination of the right + examination from hepatic flexure to rectum, divided by the total number of patients in the SFV group. Thus, if a patient has at least 1 adenoma detected on both the first examination and the second examination of the right colon, then this patient will be counted once only. For the conventional group, it is defined as the number of patients with at least 1 adenoma identified in the whole colon on the conventional withdrawal examination divided by the total number of patients in the conventional withdrawal group. | 24 months |
| The number of patients with at least 1 additional adenoma detected in right colon in the SFV group | For the SFV group, this is the additional adenoma yield on 2nd forward view exam of the right colon | 24 months |
| Adverse events during colonoscopy and up to 30 days post colonoscopy | Adverse event rate in SFV group and conventional group | 24 months |
| Total number of adenomas found on the first and second examinations of the right colon in the SFV group, and that on the examination of the right colon in the conventional group | This represents the absolute number of adenomas found on the first and second examinations of the right colon in the SFV group, and that on the examination of the right colon in the conventional group | 24 months |
| Total number of polyps found on the first and second examinations of the right colon in the SFV group, and that on the examination of the right colon in the conventional group | This represents the absolute number of polyps found on the first and second examinations of the right colon in the SFV group, and that on the examination of the right colon in the conventional group | 24 months |
| Alice Ho Miu Ling Nethersole Hospital |
| Hong Kong |
| Hong Kong |
| Prince of Wales Hospital | Hong Kong | Hong Kong |
| D007414 | Intestinal Neoplasms |
| D005770 | Gastrointestinal Neoplasms |
| D004067 | Digestive System Neoplasms |
| D009371 | Neoplasms by Site |
| D009369 | Neoplasms |
| D004066 | Digestive System Diseases |
| D005767 | Gastrointestinal Diseases |
| D003108 | Colonic Diseases |
| D007410 | Intestinal Diseases |
| D012002 | Rectal Diseases |