A145 ENDOSCOPICALLY NON-VISIBLE INTERVAL COLONIC ADENOCARCINOMA DESPITE HIGH-QUALITY SURVEILLANCE.
Bibliographic record
Abstract
Abstract Background Colonoscopy remains the gold-standard for screening and surveillance of colorectal cancer (CRC). Regular colonoscopy with polypectomy has been associated with reduced CRC incidence and mortality. However, interval CRC, defined as cancer diagnosed between initial screening and subsequent surveillance colonoscopies, occurs at rates of 2–14%. Identified risk factors for interval cancers include patient-related factors (older age, diverticular disease, proximal CRC), endoscopy-related factors (colonoscopy by non-gastroenterologists or in an outpatient setting; endoscopists with low rates of completion, adenoma detection or polypectomy) and biologic factors (microsatellite instability (MSI), CpG island methylation). We report a patient with interval metastatic ileo-cecal adenocarcinoma despite multiple, high-quality surveillance colonoscopies, not endoscopically visible as no visible intra-luminal mucosal component was present. Aims To describe a case of an interval CRC without an endoscopically visible intra-luminal component. Methods Case description and literature review. Results A 69-year-old male, with a history of multiple advanced colonic polyps requiring multiple surveillance colonoscopies and polypectomies, presented with symptoms of bowel obstruction. An abdominal CT scan revealed findings of terminal ileitis and upstream small bowel obstruction. Colonoscopy was performed, revealing obstruction of the ileo-cecal valve with a firm cecal submucosal lesion without abnormal overlying mucosal abnormalities. Exploratory laparoscopy revealed a mass at the ileo-cecal valve with associated peritoneal deposits. A right hemicolectomy was performed, and pathological examination demonstrated metastatic invasive adenocarcinoma involving the cecum, the terminal ileum and ileo-cecal valve without extension into the lumen or formation of an overt polypoid mass. The tumour extended into the wall of the distal ileum in a circumferential fashion, involving the immediate deep serosa, but with only minimal, focal mucosal ileal involvement and no overt polypoid mass. An independent review of the case and resection specimen by a second pathologist confirmed absence of significant ileal or colonic mucosal involvement and no obstructing intraluminal component. Conclusions This case illustrates a rare presentation of an interval CRC that was not identified despite several high-quality surveillance colonoscopies, as only minimal mucosal involvement was present. As endoscopy remains the gold-standard for early detection and removal of pre-malignant lesions and early malignancy, the patient’s presentation with interval malignant bowel obstruction and metastatic disease, despite adequate quality surveillance, demonstrates an inherent limitation of colonoscopy. To our knowledge, this is only the third documented case of endoscopically non-visible interval CRC. Funding Agencies NoneNone
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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 | 0.001 |
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".