A164 RISKS OF SKIN CANCERS PRE- AND POST-INFLAMMATORY BOWEL DISEASE DIAGNOSIS
Bibliographic record
Abstract
Abstract Background Inflammatory bowel disease (IBD) has been shown to be associated with an increased risk of non-melanoma skin cancers (NMSC), specifically squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), with the use of immunosuppressants such as thiopurines and tumor necrosis factor inhibitors (anti-TNFa). However, there is no literature exploring risk of skin cancers prior to formal Crohn’s disease (CD) or ulcerative colitis (UC) diagnoses. An increased risk pre IBD diagnosis could potentially suggest varied immunological impairments in patients with IBD. Aims To compare risks of NMSC and melanoma preceding and following a diagnosis of IBD and to evaluate the effect of thiopurines and anti-TNFa on risk of skin cancers in IBD. Methods This is a retrospective, historical cohort study using population-based data sources including the University of Manitoba IBD Epidemiology Database and the Manitoba Cancer Registry. Individuals with IBD diagnosed between 1987 and 2018 (N = 9344 / 636 NMSC) were identified and matched with randomly selected controls (N = 88916 / 3839 NMSC) based on age, sex, and postal area of residence on the date of IBD diagnosis (index date). Logistic and Cox regression analyses were performed to calculate adjusted risks skin cancers prior to and after IBD diagnosis. Results Subjects with IBD were more likely to have BCC pre-dating their IBD diagnosis (OR 1.50, 95% CI 1.24–1.81). Risks of SCC, other non-melanoma skin cancers, or melanoma prior to IBD diagnosis were not significantly increased. Post-IBD diagnosis, risk of BCC and SCC were significantly increased across all IBD groups (HR 1.60, 95% CI 1.45–1.76 and HR 1.65, 95% CI 1.37–1.99), except for SCC in UC. There was no significant association between melanoma and IBD post-IBD diagnosis. Thiopurines are associated with higher risks of BCC, SCC, and melanoma in IBD. Anti-TNFa use also raised risks of BCC and melanoma, but anti-TNFa alone did not increase risk of SCC in IBD. Nested case-control analysis confirmed a higher baseline risk of BCC in patient with IBD with censoring of both thiopurines and anti-TNFa. Similarly, censoring of both medications produced no effect on risk of SCC in IBD corroborating the absence of a baseline SCC risk in IBD. Conclusions The risk of BCC preceding a formal diagnosis of IBD is higher than in non-IBD controls, compared to a generally increased risk of NMSC post-IBD diagnosis. IBD is not associated with a significant risk of melanoma, although risk for melanoma is increased with thiopurine or anti-TNFa exposure. Our study suggests a possible inherent immune impairment in patients with IBD that leads to BCC. Thiopurine and anti-TNF therapy increase the risks for skin cancers evident in persons with IBD after their diagnoses. Funding Agencies 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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".