Endoscopic Appearance of Dysplasia in Ulcerative Colitis and the Role of Staining
Bibliographic record
Abstract
Objectives Cancer Risk and Surveillance Patients with longstanding extensive ulcerative colitis are at increased risk of developing colorectal cancer. Colonoscopic surveillance is recommended by most authorities in an attempt to reduce the associated mortality. Surveillance relies on the detection of premalignant dysplastic tissue, and where dysplasia is detected, proctocolectomy has historically been and currently remains the management of choice, although there is increasing evidence that adenoma-like dysplastic lesions may safely be resected endoscopically. Detection of Dysplasia in Ulcerative Colitis In patients without ulcerative colitis, the premalignant dysplastic lesion, the adenoma, usually occurs as a clearly delineated macroscopically visible abnormality. However, in ulcerative colitis there is no clear-cut adenoma-carcinoma sequence. Dysplasia can occur in polypoid lesions, but often appears as a more subtle mucosal irregularity, or may be macroscopically invisible. Because of this, most endoscopists worldwide take multiple random biopsies of flat mucosa. It has been estimated that 33 biopsies are required to provide a 90 % chance of finding the highest degree of dysplasia present [ 1 ]. It has been recommended that four random biopsies per site over nine sites throughout the colon be undertaken, with increased sampling from the rectosigmoid and with additional biopsies from raised or suspicious lesions [ 2 ]. However, it is time-consuming to take 30 - 50 nontargeted random biopsies throughout the colon, and dysplastic lesions might still be overlooked. Recent improvements in endoscopic equipment and technique, particularly the use of dye-sprays (chromoendoscopy), have improved dysplasia detection in ulcerative colitis [ 3 ] [ 4 ] [ 5 ], and reduced the colonoscopist’s dependence on random biopsies. In this report, we describe the endoscopic appearance of dysplasia, and the chromoendoscopic technique for detection of dysplasia in ulcerative colitis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".