An interventional study of High-definition white light endoscopy (WLE) and Texture and color enhancement imaging (TXI) in Colorectal Polyps, sponsored by University Hospital Virgen de las Nieves. Recruiting at 2 sites in Spain. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by University Hospital Virgen de las Nieves · Not applicable, Interventional, and Diagnostic
Large colorectal polyps removed piece by piece (piecemeal endoscopic mucosal resection) can recur at the resection scar. Detecting this residual or recurrent tissue at surveillance colonoscopy is essential, because it can then be treated endoscopically. Recurrence can be subtle, and the best way to examine the scar has not been established.
This study compares four ways of examining post-polypectomy scars:
high-definition white light endoscopy (WLE) texture and color enhancement imaging (TXI, Olympus) narrow-band imaging (NBI, Olympus) an artificial intelligence computer-aided detection system (GI Genius, Medtronic)
Each scar is examined with all four techniques, in random order. A different expert endoscopist performs each technique, without knowing the findings of the others. Biopsies are then taken from every scar, and any suspicious tissue is removed. Histology is the reference standard.
The main goal is to determine which technique, or combination of techniques, has the highest sensitivity and negative predictive value for detecting recurrence.
Background. Local recurrence after piecemeal endoscopic mucosal resection (EMR) of large non-pedunculated colorectal lesions occurs in about 15-20% of cases, and most recurrences appear within the first 6 months. Guidelines recommend a first surveillance colonoscopy 3 to 6 months after piecemeal resection and a second at 12 months. Virtual chromoendoscopy improves the detection of recurrence compared with white light, and some guidelines suggest that routine scar biopsy may be omitted when advanced imaging is used. However, newer image-enhancement modes such as TXI, and computer-aided detection (CADe) systems trained on native polyps, have not been evaluated for post-EMR scars. No study has compared these techniques with each other.
Objectives. The main objective is to identify the best method for examining post-polypectomy scars. The specific objectives are to compare the detection of residual or recurrent neoplasia between:
WLE and TXI WLE and GI Genius TXI and GI Genius NBI and each of the other modalities.
Design. Prospective, single-center, randomized crossover diagnostic accuracy study with blinded assessors, conducted at the Endoscopy Unit, Hospital Universitario Virgen de las Nieves, Granada, Spain.
Population. Adults (>18 years) referred for scar review 3 to 6 months after EMR or endoscopic submucosal dissection of a colorectal lesion ≥15 mm whose histology showed an adenoma or sessile serrated lesion. Exclusion criteria are other index lesion histology, incomplete or uncertain previous resection, and age or comorbidity precluding endoscopic surveillance. Patients with more than one scar contribute each scar separately.
Procedure.
A first expert endoscopist advances the colonoscope to the cecum with white light.
The patient is then randomized to the modality used first. The endoscopist locates the scar, records whether recurrence is present and its estimated size, takes at least 5 photographs, and leaves the colonoscope 5-10 cm proximal to the scar.
A second expert endoscopist then enters the room and assesses the scar with another modality, followed by further endoscopists for the remaining ones. Which endoscopist performs each modality is assigned at random for every case.
Each assessor is unaware of the previous findings. Nursing staff record each diagnosis on a case report form, which the endoscopists cannot consult until the end of the procedure.
Finally, 2-4 biopsies are taken from every scar, and any tissue considered residual by at least one endoscopist is resected and sent separately.
All participating endoscopists are experts, with more than 10,000 colonoscopies and more than 500 in the previous year. Specimens are assessed by expert gastrointestinal pathologists.
Recurrence is defined according to Higaki criteria: any neoplastic tissue arising within or less than 5 mm from the margins of the scar. Patients underwent a further examination at 12 months using the same protocol.
Outcomes.
Primary: sensitivity and negative predictive value of each modality for histologically confirmed recurrence.
Secondary: specificity, positive predictive value, likelihood ratios, and the sensitivity and negative predictive value of combinations of modalities (WLE+TXI, WLE+GI Genius, TXI+NBI).
Other: endoscopic characterization of recurrence (NICE classification and WASP criteria) and recurrence at the 12-month examination.
Statistical analysis. Diagnostic accuracy measures are reported with 95% confidence intervals (Wilson method). Because all modalities are applied to the same scars, comparisons are paired. The planned sample size is 205 scars, with an interim analysis after 165 scars.
Ethics. The study was approved by the Research Ethics Committee of Granada (CEIm de Granada) [SICEIA-2024-002527]. All participants gave written informed consent. Data are pseudonymized in accordance with Spanish Organic Law 3/2018 on data protection.
University Hospital Virgen de las Nieves is the lead sponsor of 13 studies on the registry; 2 are open to participants now.
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Exclusion Criteria:
Scar assessed first with high-definition white light, then with the remaining modalities by different blinded endoscopists. All scars biopsied.
Diagnostic Test: High-definition white light endoscopy (WLE)
Scar assessed first with TXI, then with the remaining modalities by different blinded endoscopists. All scars biopsied.
Device: Texture and color enhancement imaging (TXI)
Scar assessed first with GI Genius CADe, then with the remaining modalities by different blinded endoscopists. All scars biopsied.
Device: GI Genius (CADe)
Scar assessed first with Narrow Band Imaging (NBI), then with the remaining modalities by different blinded endoscopists. All scars biopsied.
Device: Narrow-band imaging (NBI)
Standard high-definition white light assessment of the post-polypectomy scar (EVIS X1, Olympus).
Image-enhancement mode of the EVIS X1 platform (Olympus) enhancing texture, brightness and color.
Virtual chromoendoscopy mode of the EVIS X1 platform (Olympus). Added by protocol amendment.
Artificial intelligence computer-aided detection system (Medtronic) used during white light assessment of the scar.
Sensitivity for histologically confirmed recurrence at the post-polypectomy scar
Proportion of scars with histologically confirmed recurrence that are correctly identified as recurrence by each modality (WLE, TXI, NBI, GI Genius). Recurrence is defined by Higaki criteria (neoplastic tissue within or \<5 mm from the scar margins). Reference standard: histology of scar biopsies and resected tissue.
Time frame: At the surveillance colonoscopy, 3 to 6 months after resection
Negative predictive value for histologically confirmed recurrence
Proportion of scars classified as free of recurrence by each modality that show no recurrence on histology.
Time frame: At the surveillance colonoscopy, 3 to 6 months after resection
Specificity and positive predictive value of each modality
Specificity and PPV of WLE, TXI, NBI and GI Genius for recurrence, against histology.
Time frame: 3 to 6 months after resection
Sensitivity and negative predictive value of combined modalities
Sensitivity and NPV of WLE+TXI, WLE+GI Genius and TXI+NBI. A combination is positive if either modality is positive.
Time frame: 3 to 6 months after resection
Diagnostic accuracy at the 12-month surveillance colonoscopy
Sensitivity and NPV of each modality for late recurrence, against histology.
Time frame: 12 months after the first surveillance colonoscopy
Endoscopic characterization of recurrence
Agreement of the NICE classification and the WASP criteria with the histological type of recurrence.
Time frame: 3 to 6 months and 12 months after resection
Plan to share: Yes — Plan to Share IPD: Yes IPD Sharing Plan Description: De-identified individual participant data underlying the results reported in the publications (diagnostic findings of each modality, histology and baseline characteristics) will be shared upon reasonable request to the principal investigator, after approval of a methodologically sound proposal and signature of a data sharing agreement. Sharing will comply with the General Data Protection Regulation and Spanish Organic Law 3/2018 and may require approval by the Research Ethics Committee of Granada.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: Beginning 6 months after publication of the main results and for 5 years thereafter.
Access criteria: Researchers submitting a methodologically sound proposal approved by the study investigators; a signed data sharing agreement is required.
Started Dec 2024 (actual). Primary completion is estimated for Dec 2026, 24 months after the start.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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University Hospital Virgen de las Nieves