A98 SURVEILLANCE COLONOSCOPIES IN ULCERATIVE COLITIS: DOES IT MAKE A DIFFERENCE?
Bibliographic record
Abstract
Patients with a background history of ulcerative colitis (UC) and Crohn’s disease (CD) have a higher risk of colorectal cancer compared to the general population. However, the benefit of surveillance colonoscopies and the ideal intervals for surveillance have not been established. This study aims to identify the association between surveillance intervals for patients in Ontario with a diagnosis of UC and the incidence and stage of identified CRC. This study was approved by the Ontario Institute for Clinical Evaluative Sciences (ICES), which permitted access to data from the Ontario Cancer Registry (OCR) and Ontario Health Insurance Plan Claims (OHIP). This allowed us to retrospectively identify UC patients diagnosed from 1994 onwards with an OHIP billing code 556 and their incidence of CRC with an OHIP billing code 153. In addition, by using the ICES data, access to the Discharge Abstract Database (DAD) and Registered Persons Database (RPDB) further allowed stratification of the patients by comorbidities, age and gender respectively. The primary endpoint was a comparison of CRC stage at the time of CRC diagnosis between patients who did not have screening colonoscopies, average screening interval ≤ 3 years and an average screening interval > 3 years. We defined low risk CRC stage as patients according to the Cancer Care Society (CCS) to have a 5-year survival > 80% compared to high risk CRC as patients with 5-year survival < 80%. According to CCS, CRC stages I, IIa, III and IIIa were classified as low risk and CRC stages IIb, IIc, IIIb, IIIc, IIINOS, IV were high risk. Data was then analyzed by SAS 9.4 statistical software. Chi-square testing was used to compare these incidences. Within the ICES database, a total of 264 UC patients developed CRC and had staging information available. Among these patients, those who had average follow-up colonoscopies at a frequency ≤ 3 years presented with an earlier stage of CRC (58.6% of the time) compared to those with follow-up colonoscopies at a frequency of > 3 years (44% of the time) and those with no follow-up (18.5% of the time) (Mantel-Haenszel chi-square p value <0.001). In addition, when looking at long term follow-up at 15-year, there was a survival benefit shown in those CRC individuals who had average colonoscopies ≤ 3 years (75.12%) compared to follow-up > 3 years (70.1%) and no follow-up (57.8%); the p-value = 0.0042. Those UC patients who underwent colonoscopies on average intervals of ≤ 3 years had their CRC detected at earlier stages compared to those who underwent follow-up colonoscopies at > 3 year intervals or those who did not have follow-up colonoscopies. This supports a surveillance interval for UC of ≤ 3 years. Table 1: Incidence of CRC stage based on colonoscopy surveillance interval None
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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 | 0.005 | 0.033 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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".