Low incidence of colorectal cancer in Australian ulcerative colitis patients
Bibliographic record
Abstract
Background: Ulcerative colitis (UC) causes significant morbidity and patients may ultimately require colectomy. UC is also associated with an increased risk of developing colorectal cancer (CRC), which may be as high as 18% after 30 years although some recent studies have reported lower rates. Aims: This study aimed to ascertain the cumulative incidences of colectomy and CRC in Australian UC patients. Methods: The study is based on a prevalence cohort (1977–1992) of Sydney IBD patients was fi rst described in 1995 and longitudinally followed. UC patients were included in this analysis if they were either diagnosed after 1977 or had yet to experience colectomy or CRC in 1977 Cumulative incidences for colectomy and CRC were calculated by competing risk survival analysis using the statistical software R. Phenotyping was performed using the Montreal Classification. The influence of extent of colitis, sex, age at diagnosis and year of diagnosis on cumulative incidences were also examined. Results: 504 patients (267 males, median age at diagnosis 34 years) were followed up for a median of 14 years (8006 patient years). The cumulative incidence of colectomy was 15% (95% CI 11%–19%) after 10 years, 26% (95% CI 21%–30%) after 20 years and 31% (95% CI 25–36%) by 30 years. Pancolitis was associated with an increased risk of colectomy (hazard ratio of 13.15; 95% CI 3.2–54.01, P < 0.001), but neither age at diagnosis nor year of diagnosis influenced colectomy risk. CRC occurred in 24 patients for a cumulative incidence of CRC of 1% (95% CI 0–2%) at 10 years, 3% (95% CI 1–5%) at 20 years and 7% (95% CI 4%–10%) at 30 years. Patients diagnosed before 1980 had a hazard ratio for CRC of 5.2 (95% CI 1.74–15.5, P = 0.003) compared to those diagnosed ≥1980. The extent of colitis (left-sided versus pancolitis) was not found to influence CRC risk possibly due the small number of cancers (P = 0.8).Conclusion: We have demonstrated a very low incidence of CRC in this Australian cohort of UC patients. The decreased risk of developing CRC in patients diagnosed after 1980 suggests a positive effect from modern management by dedicated gastroenterologists. The finding of lower cancer rates than in other cohorts should reassure patients and physicians alike. Only a quarter of patients required colectomy within 20 years and the risk was higher for patients with pancolitis.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".