Anorectal Cancer in Crohn's Disease: A Systematic Review
Bibliographic record
Abstract
Introduction: Anorectal cancer (ARC) associated with Crohn's disease (CD) is a rare but serious complication, with limited data available in the literature.Objective: To evaluate the incidence and clinical characteristics of ARC in patients with CD.Methods: A systematic review was conducted following PRISMA guidelines.A PubMed search (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023)(2024) identified studies using the keywords "anorectal cancer", "Crohn's disease", and "inflammatory bowel disease".Articles in English and Portuguese, or with an English abstract containing extractable data, were included.Variables analyzed included age at diagnosis, tumor type, fistula characteristics, symptoms, treatment, and survival.Study quality was assessed using the Newcastle-Ottawa Scale.Results: Eight studies (6 retrospective, 2 case reports) with 87 patients were included.ARC incidence among CD patients ranged from 0.54% to 0.8%.Most cases occurred in males (61.2%) with early CD diagnosis (mean age 21-25.5 years).ARC was diagnosed at a mean age of 46.7 years, with a mean interval of 25.6 years from CD diagnosis.Tumors were mainly adenocarcinomas (52.6%-85.7%).Diagnosis often followed biopsy of asymptomatic chronic perianal fistulas (47.4%-81.3%).Metastasis was present at diagnosis in 36.8%.Most patients underwent radical surgery.Recurrence occurred in 35.7%, and overall survival was 68.3%.Conclusion: ARC in CD is rare but aggressive.Early diagnosis is challenging, especially in chronic perianal fistulas.Prolonged surveillance and effective screening are crucial.
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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 | 0.006 | 0.023 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.007 | 0.005 |
| Bibliometrics | 0.009 | 0.012 |
| 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".