Evaluation of the Ileo-anal Pouch in FAP (ENDOPOL) (ENDOPOL)

ENDOPOL: Dye chromoENDOscopy Versus Virtual Chromoendoscopy for Assessment of the Ileo-anal Pouch in Patients With Familial Adenomatous POLyposis: a Randomized Controlled Trial

This international, multi-centre randomised controlled trial will compare dye-based chromoendoscopy with virtual chromoendoscopy, using NBI/BLI, for adenoma detection during routine surveillance pouchoscopy in adults with familial adenomatous polyposis (FAP) and an ileal pouch-anal anastomosis (IPAA). The estimated study duration is 2 years. Participants will undergo their usual scheduled pouchoscopy, performed by endoscopists experienced in FAP. Before the procedure, they will be randomised 1:1 to dye-based or virtual chromoendoscopy. Adenomas requiring endoscopic treatment will be removed during the same procedure according to standard practice.

To our knowledge, no previous study has directly compared these techniques in this setting. Current guidelines recommend surveillance in patients with FAP and a pouch and permit dye-spray chromoendoscopy, but do not specify whether dye-based or virtual chromoendoscopy should be preferred. Practice varies between centres: virtual chromoendoscopy is commonly used at St Mark's Hospital, while some European centres primarily use dye-based chromoendoscopy. This study therefore aims to standardise practice and generate evidence to inform future surveillance strategies.

Eligible patients will be adults aged ≥18 years with FAP, defined by a proven APC germline mutation or a clinical diagnosis of >100 colorectal adenomas with a positive family history, and who have undergone IPAA after primary proctocolectomy or secondary proctectomy following IRA/ISA. Patients will be identified through routine endoscopy booking systems. Those who have consented to email communication from the Polyposis Registry team will receive a Participant Information Sheet in advance. They will be approached again on the day of their procedure, given the opportunity to ask questions, and consented before randomisation. Patients who do not consent will undergo their planned pouchoscopy as normal, without study randomisation. Patients lacking capacity to consent will not be approached.

Randomisation will be performed using an independent computer-generated programme within Castor EDC, with allocation in a 1:1 ratio. Block randomisation will ensure balanced distribution between arms within each centre, and stratification by centre will account for differences in patient characteristics and local practice. Blinding is not feasible because dye-based and virtual chromoendoscopy have visually distinct appearances.

During pouchoscopy, the pre-pouch ileum, pouch body and rectal cuff will be carefully inspected. In the dye-based arm, indigo carmine will be applied using a spray catheter before withdrawal and mucosal inspection. In the virtual chromoendoscopy arm, inspection will be performed using NBI/BLI according to local platform availability. The endoscope will be advanced to the pre-pouch ileum, followed by systematic withdrawal and spiral mucosal inspection. Lesions will be documented by size and location, including pouch body and rectal remnant/rectal cuff, using a polyp burden scoring table. Retroflexion will be performed to assess the rectal cuff. Polyp size will be estimated in millimetres, supported where appropriate by biopsy forceps of known size. Adenomas will be resected using standard polypectomy techniques where indicated, including polyps >5 mm in the pouch body, >2 mm in the rectal cuff, or lesions suspicious for high-grade dysplasia or early cancer.

Because assessment of small polyps can vary between endoscopists, particularly for lesions <5 mm, endoscopic images will be used to assess inter-rater and intra-rater reliability for polyp burden and size. If reliability is acceptable, smaller polyps will be included and reported.

Quality parameters will be collected for each procedure, including adjusted Boston Bowel Preparation Scale assessment for the pouch and total procedural time. Procedural time will include scope introduction, irrigation, dye application where applicable, withdrawal and inspection, retroflexion, and removal and retrieval of polyps.

Post-procedure follow-up will follow routine care. Patients will be asked to monitor for adverse events after pouchoscopy and contact the hospital if needed. Future surveillance will be scheduled according to each centre's usual policy.

Study data will be held in routine hospital systems accessible to the patient's usual clinical team and in a study file. Participants will be assigned a study number. No identifiable patient information will leave the Trust or be accessible to anyone outside the usual care team. Anonymised data will be entered into Castor EDC. Pseudonymised data will be transferred to the central study team at Amsterdam University Medical Center under an existing data transfer agreement for pooled analysis.

The study does not expose participants to risks beyond routine surveillance pouchoscopy. There is no direct individual benefit but findings may benefit future patients with FAP and families by improving evidence.

Study Overview

• Status: Recruiting
• Conditions: Familial Adenomatous Polyposis (FAP); Pouches, Ileoanal
• Intervention / Treatment: Other: Chromoendoscopy (Indigo Carmine); Other: Virtual Chromoendoscopy

Detailed Description

This study is an international, multicentre, randomised controlled trial comparing dye-based chromoendoscopy with virtual chromoendoscopy during surveillance pouchoscopy in adults with familial adenomatous polyposis and an ileal pouch-anal anastomosis. The anticipated study duration is approximately 2 years.

Following restorative proctocolectomy, adenomas may develop within the ileal pouch, rectal cuff or pre-pouch ileum. Continued endoscopic surveillance is therefore recommended because progressive adenomatous change may be associated with high-grade dysplasia or malignancy. Current surveillance guidelines permit the use of enhanced endoscopic imaging but do not specify a preferred chromoendoscopy technique because comparative evidence in this setting remains limited.

Dye-based chromoendoscopy involves topical application of contrast dye to enhance mucosal surface architecture and lesion margins. Virtual chromoendoscopy uses optical or digital image-enhancement technologies, including narrow-band imaging or blue-light imaging, to improve visualisation of mucosal and vascular patterns without routine application of contrast dye. Both approaches are established in clinical endoscopy, although practice varies between centres. Virtual chromoendoscopy is commonly used at St Mark's Hospital, whereas dye-based chromoendoscopy remains the predominant approach at several other European centres.

No adequately powered randomised study has directly compared dye-based and virtual chromoendoscopy for surveillance of an ileal pouch in familial adenomatous polyposis. The relative ability of each technique to identify clinically relevant adenomas, characterise overall polyp burden and support reproducible lesion measurement therefore remains uncertain. The present study is intended to provide comparative evidence, reduce variation in surveillance practice and inform future recommendations regarding the optimal imaging approach.

Participant identification and enrolment

Potential participants scheduled for clinically indicated surveillance pouchoscopy will be identified by the local clinical team through endoscopy booking systems, polyposis registries or equivalent institutional records. Study information may be provided electronically or by another locally approved method before the planned procedure. Potential participants will have an opportunity to review the study information and raise questions before enrolment.

Final confirmation of eligibility and written informed consent will occur before the surveillance procedure. Participation will not alter the clinical indication for pouchoscopy. Declining participation will not affect the scheduled procedure, subsequent care or future surveillance.

Randomisation will occur after consent and before insertion of the endoscope. The allocated imaging technique will be used during the diagnostic inspection phase of the pouchoscopy.

Randomisation and allocation

Randomisation will be performed through Castor Electronic Data Capture using an independent computer-generated allocation sequence. Allocation will occur in a 1:1 ratio between dye-based chromoendoscopy and virtual chromoendoscopy.

Variable block sizes of 2, 4 and 6 will be used to preserve allocation balance while reducing the predictability of subsequent assignments. Randomisation will be stratified by participating centre to account for potential centre-level differences in participant characteristics, endoscopy platforms, surveillance practices and procedural technique.

The allocation sequence will be concealed within the electronic randomisation system until enrolment and confirmation of eligibility have been completed. Access to the randomisation module will be limited to authorised study personnel at participating centres.

Blinding of the endoscopist is not feasible because dye-based and virtual chromoendoscopy have distinct procedural and visual characteristics. Participant blinding may also be impractical when pouchoscopy is performed under no sedation or mild conscious sedation. Histopathological assessment will be undertaken according to local routine practice, with pathological interpretation based on submitted specimens rather than the assigned endoscopic imaging technique.

Endoscopic procedure

Surveillance pouchoscopy will be performed by endoscopists with experience in familial adenomatous polyposis and ileal pouch surveillance. Procedures will follow local clinical standards and applicable national or European guidance.

The examination will include the pre-pouch ileum, pouch body and rectal cuff or retained rectal mucosa. The endoscope will be advanced to the pre-pouch ileum, followed by systematic withdrawal and circumferential mucosal inspection. A spiral withdrawal technique will be encouraged to maximise visualisation of the mucosal surface. Irrigation and suction will be used as required to remove residual debris, mucus or fluid.

Retroflexion will be performed within the pouch when considered technically feasible and clinically appropriate, allowing detailed inspection of the rectal cuff, anastomosis and distal pouch. Any limitation affecting mucosal visualisation, including inadequate preparation, retained contents, luminal narrowing, inflammation or technical difficulty, will be documented.

Dye-based chromoendoscopy group

In the dye-based chromoendoscopy group, the pre-pouch ileum, pouch body and rectal cuff will be examined following topical application of indigo carmine. Dye will be applied through a spray catheter or another standard endoscopic delivery device.

Application will be sufficiently diffuse to enhance mucosal topography across the relevant anatomical regions. Additional targeted dye application may be undertaken when an area requires closer inspection. Following dye application, the mucosa will be examined systematically during withdrawal of the endoscope.

Indigo carmine functions as a contrast agent by pooling within mucosal grooves and depressions, thereby accentuating surface irregularities and lesion borders. Detection, characterisation and documentation of suspected adenomas will occur during the dye-enhanced inspection phase.

Virtual chromoendoscopy group

In the virtual chromoendoscopy group, the pre-pouch ileum, pouch body and rectal cuff will be examined using narrow-band imaging, blue-light imaging or an equivalent compatible virtual chromoendoscopy mode available on the endoscopy platform at the participating centre.

Virtual chromoendoscopy will be activated during systematic mucosal inspection. White-light imaging may be used for initial orientation, irrigation and identification of anatomical landmarks. The allocated virtual chromoendoscopy mode will then be used for detailed lesion detection and characterisation.

Routine indigo carmine application will not be used during the primary diagnostic inspection in this group. Targeted dye application may only be undertaken when required for clinical safety or management after completion of the allocated diagnostic assessment. Any such use will be recorded as a procedural deviation or additional clinical intervention, as appropriate.

Lesion detection and documentation

All detected lesions will be documented according to anatomical location, estimated size and endoscopic appearance. Location will be recorded separately for the pre-pouch ileum, pouch body and rectal cuff or rectal remnant.

Lesion size will be estimated in millimetres. A closed or open biopsy forceps with known dimensions will be used as a visual reference where appropriate. The largest estimated diameter will be recorded. Standardised study guidance will be provided to reduce variability in the measurement of small lesions.

Polyp burden will be recorded using study-specific scoring tables. Separate assessments will be completed for the pouch body and rectal cuff, with an additional combined assessment representing overall pouch-related polyp burden. The scoring framework will account for lesion number, lesion size and anatomical distribution.

Endoscopic images will be captured for representative lesions and relevant anatomical regions. Images will be obtained in a standardised manner where possible and will include a size reference when technically feasible. Image capture will support central or secondary assessment of lesion size and polyp burden.

Lesions with features suspicious for advanced neoplasia will be documented in detail. Relevant features may include irregular morphology, ulceration, spontaneous bleeding, depression, disrupted vascular pattern, marked surface irregularity or a non-lifting appearance. Management of such lesions will follow established clinical practice and local governance arrangements.

Endoscopic treatment

After completion of the allocated diagnostic inspection and documentation of polyp burden, adenomas meeting criteria for endoscopic treatment will be removed using standard polypectomy techniques.

Indications for polypectomy will include:

• lesions larger than 5 mm within the pouch body;
• lesions larger than 2 mm within the rectal cuff or retained rectal mucosa; and
• lesions with endoscopic features suspicious for high-grade dysplasia or early malignancy.

Removal techniques may include cold biopsy forceps, cold snare polypectomy, hot snare polypectomy or another clinically appropriate method. Selection of the resection technique will depend on lesion size, morphology, location and local practice.

Resected tissue will be retrieved for histopathological examination whenever clinically appropriate. Histological assessment will follow local pathology protocols. Relevant pathological features may include adenomatous histology, grade of dysplasia, completeness of excision where assessable and evidence of invasive malignancy.

Clinical management arising from histopathological findings will remain the responsibility of the treating clinical team and will follow local multidisciplinary pathways.

Reliability assessment

Variation in endoscopic estimation of polyp size and burden may be particularly important for lesions smaller than 5 mm. A structured reliability assessment will therefore be incorporated into the study.

Participating endoscopists will assess a standardised set of endoscopic images showing lesions and representative polyp burden. Each assessor will record lesion size and the corresponding polyp-burden category using the study scoring system.

The same image set will be reassessed after an interval of approximately 1 week. The order of images may be altered during the repeat assessment to reduce recall effects.

Inter-rater reliability will be calculated to quantify agreement between endoscopists. Intra-rater reliability will be calculated to quantify consistency within individual assessors across the two assessment time points. Statistical methods appropriate to the scale and distribution of the measurements will be used, including correlation coefficients, intraclass correlation coefficients or kappa statistics where applicable.

The reliability analysis will inform the interpretation of data relating to small adenomas. Lesions smaller than 5 mm will be included in relevant analyses when measurement and classification demonstrate acceptable reproducibility. Sensitivity analyses may be performed using alternative lesion-size thresholds where reliability is insufficient.

Procedural quality parameters

Standardised quality parameters will be collected for each pouchoscopy. Bowel preparation and mucosal cleanliness will be assessed using an adapted Boston Bowel Preparation Scale suitable for pouchoscopy. Scores will reflect the quality of visualisation within the relevant pouch segments. Additional cleansing performed during the procedure will also be recorded where required by the case report form.

Total procedure duration will be recorded. Procedural time will include endoscope insertion, irrigation, suction, dye application in the dye-based chromoendoscopy group, activation and use of virtual chromoendoscopy, systematic mucosal inspection, retroflexion, lesion documentation, polypectomy, specimen retrieval and endoscope withdrawal.

Factors affecting procedural duration will be documented where relevant, including extensive polyp burden, difficult anatomy, poor preparation, therapeutic intervention or technical equipment issues.

Additional procedural information may include sedation, completeness of examination, depth of insertion into the pre-pouch ileum, use of retroflexion, number of lesions removed, polypectomy technique and immediate adverse events.

Post-procedure management

Immediate post-procedure care will follow routine clinical practice at each participating centre. Participants will receive standard advice regarding symptoms requiring medical review after pouchoscopy or polypectomy.

Potential adverse events may include abdominal pain, bleeding, perforation, post-polypectomy syndrome, sedation-related complications or another clinically significant event. Adverse events identified during the procedure or reported after discharge will be documented and managed according to local clinical pathways and study reporting requirements.

Subsequent surveillance pouchoscopy will be scheduled according to local policy, clinical findings, histopathological results and applicable guidelines. The study allocation will not determine the interval to the next surveillance procedure.

Data collection and management

Study data will be recorded in Castor Electronic Data Capture using standardised electronic case report forms. Each participant will be assigned a unique study identification number.

Data entered into the central study database will not include directly identifying information. The participant identification log linking study numbers to local identifiers will remain securely stored at the recruiting centre and accessible only to authorised personnel.

Source data will remain within routine clinical systems and study files at each participating institution. Relevant source documentation may include endoscopy reports, pathology reports, procedure records, adverse-event documentation and endoscopic images.

Pseudonymised study data will be transferred to the central study team at Amsterdam University Medical Center for data management, pooling and statistical analysis. Data transfer will occur under an applicable data-transfer agreement and in accordance with institutional, national and European data-protection requirements.

Database access will be role-based and password-protected. Data validation checks, range checks and query resolution procedures will be used to support completeness and accuracy. Participating centres may be asked to clarify missing, inconsistent or implausible entries.

Endoscopic images used for reliability or central review will be pseudonymised before transfer. Image files will not contain names, hospital numbers, dates of birth or other direct identifiers.

The final analytical dataset will combine pseudonymised data from participating centres. Statistical analysis will be undertaken according to a prespecified statistical analysis plan. Any protocol deviations affecting allocation, imaging technique, completeness of examination or data integrity will be recorded and considered during analysis.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Andrew Latchford, MBBS PhD FRCP; Phone Number: +442088643232; Email: andrew.latchford@nhs.net
• Study Contact Backup: Name: Benjamin Zare, MBChB (Hons) MRCP; Phone Number: +442088643232; Email: b.zare@nhs.net

Study Locations

• United Kingdom
  • London
    • London, London, United Kingdom, N10 7NS
      • Recruiting
      • St Mark's Hospital Polyposis Registry (St Mark's Centre for Familial Intestinal Cancer)
      • Contact: Andrew Latchford, MBBS PhD FRCP; Phone Number: +442088643232; Email: andrew.latchford@nhs.net
      • Contact: Benjamin Zare, MBChB (Hons) MRCP; Phone Number: +442088643232; Email: b.zare@nhs.net

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

ALL of the following:

1. Diagnosis of FAP i.e., at least one of following:

   • Genetic diagnosis: proven APC germline mutation OR
   • Clinical diagnosis: >100 colorectal adenomas in combination with a positive family history of FAP
2. Have an ileal-pouch anal anastomosis (IPAA), either after primary proctocolectomy or secondary proctectomy after initial colectomy and ileorectal or ileosigmoidal anastomosis (IRA/ISA)
3. Age ≥ 18 years

Exclusion Criteria:

ANY of the following

1. Diagnosis of FAP i.e., at least one of following:

   • Genetic diagnosis: proven APC germline mutation OR
   • Clinical diagnosis: >100 colorectal adenomas in combination with a positive family history of FAP
2. Have an ileal-pouch anal anastomosis (IPAA), either after primary proctocolectomy or secondary proctectomy after initial colectomy and ileorectal or ileosigmoidal anastomosis (IRA/ISA)
3. Age ≥ 18 years

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Chromoendoscopy; Chromoendoscopy arm using dye spray	Other: Chromoendoscopy (Indigo Carmine); Chromoendoscopy using dye spray
Active Comparator: Virtual Chromoendoscopy; Virtual chromoendoscopy arm using narrow-band imaging (NBI)	Other: Virtual Chromoendoscopy; Virtual chromoendoscopy using narrow-band imaging (NBI)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of clinically relevant adenomas greater than 5 mm in the ileo-anal pouch	Incidence of clinically relevant adenomas greater than 5 mm in the ileo-anal pouch comparing dye-based chromoendoscopy with virtual chromoendoscopy using NBI/BLI	Periprocedural

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of advanced neoplasia in the pouch	Incidence of advanced neoplasia in the pouch, defined as advanced adenoma ≥10 mm and/or adenoma with high-grade dysplasia, or cancer	Periprocedural
Incidence of adenomas measuring 2-4 mm, 5-9 mm and ≥10 mm	Incidence of adenomas measuring 2-4 mm, 5-9 mm and ≥10 mm in the pouch body and rectal cuff	Periprocedural
Number of adenomas in the rectal remnant and anal mucosa	Number of adenomas in the rectal remnant and anal mucosa	Periprocedural
InSiGHT Polyposis Staging System score	InSiGHT Polyposis Staging System score	Periprocedural
Number of polypectomies performed	Number of polypectomies performed per procedure	Periprocedural
Length/duration of individual procedures	Length/duration of individual procedures	Periprocedural
Incidence of endoscopy-related complications	Incidence of endoscopy-related complications	Periprocedural
Interval between surveillance endoscopies, based on the personalised endoscopic surveillance protocol	Interval between surveillance endoscopies, based on the personalised endoscopic surveillance protocol used across the European FAP Consortium	From date of randomization until the date of last procedure, assessed up to 60 months

Collaborators and Investigators

• Sponsor: London North West Healthcare NHS Trust
• Collaborators: Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)
• Investigators: Principal Investigator: Andre Latchford, MBBS PhD FRCP, LONDON NORTH WEST UNIVERSITY HEALTHCARE NHS TRUST

Publications and helpful links

General Publications

• Lai EJ, Calderwood AH, Doros G, Fix OK, Jacobson BC. The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research. Gastrointest Endosc. 2009 Mar;69(3 Pt 2):620-5. doi: 10.1016/j.gie.2008.05.057. Epub 2009 Jan 10.
• Lynch PM, Morris JS, Wen S, Advani SM, Ross W, Chang GJ, Rodriguez-Bigas M, Raju GS, Ricciardiello L, Iwama T, Rossi BM, Pellise M, Stoffel E, Wise PE, Bertario L, Saunders B, Burt R, Belluzzi A, Ahnen D, Matsubara N, Bulow S, Jespersen N, Clark SK, Erdman SH, Markowitz AJ, Bernstein I, De Haas N, Syngal S, Moeslein G. A proposed staging system and stage-specific interventions for familial adenomatous polyposis. Gastrointest Endosc. 2016 Jul;84(1):115-125.e4. doi: 10.1016/j.gie.2015.12.029. Epub 2016 Jan 6.
• van Leerdam ME, Roos VH, van Hooft JE, Dekker E, Jover R, Kaminski MF, Latchford A, Neumann H, Pellise M, Saurin JC, Tanis PJ, Wagner A, Balaguer F, Ricciardiello L. Endoscopic management of polyposis syndromes: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy. 2019 Sep;51(9):877-895. doi: 10.1055/a-0965-0605. Epub 2019 Jul 23.
• Wang L, Mannalithara A, Singh G, Ladabaum U. Low Rates of Gastrointestinal and Non-Gastrointestinal Complications for Screening or Surveillance Colonoscopies in a Population-Based Study. Gastroenterology. 2018 Feb;154(3):540-555.e8. doi: 10.1053/j.gastro.2017.10.006. Epub 2017 Oct 12.
• Huneburg R, Heling D, Kaczmarek DJ, van Heteren P, Olthaus M, Fimmers R, Berger M, Coch C, Lau JF, Kristiansen G, Weismuller TJ, Spier I, Aretz S, Strassburg CP, Nattermann J. Dye chromoendoscopy leads to a higher adenoma detection in the duodenum and stomach in patients with familial adenomatous polyposis. Endosc Int Open. 2020 Oct;8(10):E1308-E1314. doi: 10.1055/a-1220-6699. Epub 2020 Sep 22.
• Hurley JJ, Thomas LE, Walton SJ, Thomas-Gibson S, Haycock A, Suzuki N, Mort M, Williams G, Morgan M, Clark SK, Sampson JR, Dolwani S. The impact of chromoendoscopy for surveillance of the duodenum in patients with MUTYH-associated polyposis and familial adenomatous polyposis. Gastrointest Endosc. 2018 Oct;88(4):665-673. doi: 10.1016/j.gie.2018.04.2347. Epub 2018 Apr 24.
• Dekker E, Boparai KS, Poley JW, Mathus-Vliegen EM, Offerhaus GJ, Kuipers EJ, Fockens P, Dees J. High resolution endoscopy and the additional value of chromoendoscopy in the evaluation of duodenal adenomatosis in patients with familial adenomatous polyposis. Endoscopy. 2009 Aug;41(8):666-9. doi: 10.1055/s-0029-1214980. Epub 2009 Aug 10.
• Pasquer A, Benech N, Pioche M, Breton A, Rivory J, Vinet O, Poncet G, Saurin JC. Prophylactic colectomy and rectal preservation in FAP: systematic endoscopic follow-up and adenoma destruction changes natural history of polyposis. Endosc Int Open. 2021 Jul;9(7):E1014-E1022. doi: 10.1055/a-1467-6257. Epub 2021 Jun 17.
• Friederich P, de Jong AE, Mathus-Vliegen LM, Dekker E, Krieken HH, Dees J, Nagengast FM, Vasen HF. Risk of developing adenomas and carcinomas in the ileal pouch in patients with familial adenomatous polyposis. Clin Gastroenterol Hepatol. 2008 Nov;6(11):1237-42. doi: 10.1016/j.cgh.2008.06.011. Epub 2008 Oct 10.
• Tajika M, Niwa Y, Bhatia V, Tanaka T, Ishihara M, Yamao K. Risk of ileal pouch neoplasms in patients with familial adenomatous polyposis. World J Gastroenterol. 2013 Oct 28;19(40):6774-83. doi: 10.3748/wjg.v19.i40.6774.
• Tudyka VN, Clark SK. Surgical treatment in familial adenomatous polyposis. Ann Gastroenterol. 2012;25(3):201-206.

Study record dates

Study Major Dates

• Study Start (Actual): July 9, 2026
• Primary Completion (Estimated): July 9, 2031
• Study Completion (Estimated): July 9, 2031

Study Registration Dates

• First Submitted: July 10, 2026
• First Submitted That Met QC Criteria: July 21, 2026
• First Posted (Actual): July 24, 2026

Study Record Updates

• Last Update Posted (Actual): July 24, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Endoscopy; Chromoendoscopy; FAP; Pouch; Dye spray
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Genetic Diseases, Inborn; Intestinal Diseases; Neoplasms by Histologic Type; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Colorectal Neoplasms; Intestinal Neoplasms; Neoplasms, Glandular and Epithelial; Colonic Diseases; Adenoma; Neoplastic Syndromes, Hereditary; Adenomatous Polyps; Intestinal Polyposis; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Adenomatous Polyposis Coli; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Indoles; Indigo Carmine
• Other Study ID Numbers: RD25/099; 365649 (Other Identifier: IRAS Project ID)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be made openly available because the study involves a relatively small and potentially identifiable clinical population. Even after de-identification, there may remain a residual risk of re-identification when clinical, demographic, procedural and outcome data are combined. In addition, participants will have consented for their data to be used for the purposes of this study and related ethically approved analyses, rather than for unrestricted external sharing. Requests for access to anonymised aggregate data or specific analyses may be considered by the study team on a case-by-case basis, subject to appropriate ethical, governance and data-sharing approvals.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No