A75 COLONOSCOPY COLORECTAL CANCER DETECTION - HOW DOES IT VARY BY INDICATION, SETTING AND PATIENT DEMOGRAPHIC?
Bibliographic record
Abstract
Abstract Background Because of limited access to gastrointestinal (GI) endoscopy during the COVID-19 pandemic, there is a need to prioritize procedures to avoid negative health impacts from delays. Ontario Health (OH) has provided guidance to facilities to prioritize colonoscopies in people with an abnormal fecal immunochemical test (FIT) result, based on the high likelihood to detect invasive colorectal cancer (CRC) and recommends FIT for screening people at average risk of CRC and those with prior low-risk adenoma. Purpose To measure the invasive CRC detection rate (CDR) of colonoscopies performed in Ontario by indication, setting, age, and sex over a 31-month period before and during the COVID-19 pandemic. Method We calculated the CDRs among outpatients ages 18 and over who had colonoscopies performed in a hospital or private clinic setting from June 2019 to December 2021. We identified hospital colonoscopies from OH’s GI Endoscopy Data Submission Portal and clinic colonoscopies from Ontario Health Insurance Plan (OHIP) data (OHIP code E749A). Invasive CRC was identified from the Ontario Cancer Registry (OCR) as: ICD-O-3 codes C18.0, C18.2-C18.9, C19.9, C20.9, a morphology indicative of CRC, microscopically confirmed and with a pathology report. CRCs were included if diagnosed 7 days before and up to 183 days after colonoscopy. Colonoscopy volumes and CDRs were stratified by age and sex (all volumes), and, for hospital colonoscopies, by indication. Result(s) During the study period, 984,109 colonoscopies were performed (638,900 in hospitals; 345,209 in clinics). Patients who had their colonoscopies in clinics were younger than those who had them in hospitals (Table 1). In both settings, colonoscopies were evenly distributed by sex. Overall, 12,021 CRCs were detected (CDR: 1.22%); 9,451 CRCs in hospitals (CDR: 1.48%), and 2,570 CRCs in clinics (CDR: 0.74%). CDRs at any age were lower in clinics as compared to hospitals. In hospitals, CDRs by colonoscopy indication were: 5.16% for FIT+, 1.93% in symptomatic patients, 0.52% in surveillance, 0.70% in average-risk screening, and 0.35% in screening due to family history. FIT+ colonoscopies accounted for the smallest proportion of colonoscopies (6.2%) but the 2nd largest proportion of CRCs detected (Figure 1). Hospital-based CDR increased during the period of observation from 1.23% pre-pandemic (June-December 2019) to 1.55% during the pandemic (January-December 2021). Clinic CDR was 0.71% pre-pandemic and 0.75% during the pandemic. Image Conclusion(s) In Ontario, colonoscopy yield (CDR) is highest in FIT+ patients; just over one in 20 colonoscopies will yield a diagnosis of CRC. In contrast, primary screening and surveillance indications have very low CRC yields. The overall yield of colonoscopies in clinics, for all age groups, is lower than in hospital setting. There was a slight increase in CDR during the pandemic compared to before the pandemic, in both settings. Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; Ontario Health - Cancer Care Ontario Disclosure of Interest None Declared
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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 | 0.036 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".