Crohn's disease (CD) with specific features that elevate cancer risk beyond the broader R...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-CHRONIC-IBD-CROHNS-SPECIFIC-PREVENTION`
Type	Red flag
Status	reviewed 2026-05-20 \| pending_clinical_signoff
Diseases	`DIS-CRC`
Sources	`SRC-AGA-IBD-CRC-2024` `SRC-BEAUGERIE-CESAME-2013` `SRC-ESMO-CRC-2024`

Red Flag Origin

Definition	Crohn's disease (CD) with specific features that elevate cancer risk beyond the broader RF-IBD-CRC-PREVENTION (which covers UC and Crohn- colitis sharing colon-inflammation pathway). This Crohn-specific anchor captures the distinct cancer signals: (1) small bowel adenocarcinoma — Crohn's patients with chronic small-bowel inflammation (especially distal ileum) carry RR ~20-40 vs. population baseline for small bowel adenocarcinoma; absolute lifetime risk remains low (~0.5-2%) because small-bowel adenocarcinoma is rare at baseline, but Crohn's is one of the few definable high-risk cohorts worth flagging. (2) Lymphoma — Crohn's disease per se elevates lymphoma risk modestly (RR ~1.5-2 in immunosuppressant-naive cohorts; higher with anti-TNF + thiopurine combinations, but that iatrogenic signal is captured by RF-IATROGENIC-ANTI-TNF-LYMPHOMA- PREVENTION and RF-IATROGENIC-AZATHIOPRINE-LONGTERM...
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "inflammatory_bowel_disease_crohn_disease_small_bowel_ge_8y",
      "value": true
    },
    {
      "finding": "inflammatory_bowel_disease_crohn_disease_with_stricture_or_fistula",
      "value": true
    },
    {
      "finding": "inflammatory_bowel_disease_crohn_disease_extensive_disease_ge_10y",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

v0.3 wave-N niche pathway — Crohn's-disease-specific cancer prevention. Distinct from the broader RF-IBD-CRC-PREVENTION (which covers UC ≥8y + Crohn-colitis ≥8y + PSC-IBD — focused on colorectal cancer via colitis-associated dysplasia pathway). This Crohn-specific RF adds three signals: (1) Small bowel adenocarcinoma in chronic distal-ileum inflammation cohort (RR ~20-40 vs. population, absolute ~0.5- 2%). No validated surveillance protocol — capsule endoscopy or MR enterography has been studied in case series but no evidence-based recommendation. Clinical vigilance for new-onset obstructive symptoms, unexplained anemia, unintended weight loss is the actionable component. (2) Lymphoma — Crohn's per se RR ~1.5-2 (immunosuppressant- naive). The iatrogenic component (anti-TNF + thiopurine combination → hepatosplenic T-cell lymphoma + EBV-driven post-transplant-like B-cell lymphomas) is captured by existing dedicated iatrogenic RFs (RF-IATROGENIC-ANTI-TNF- LYMPHOMA-PREVENTION, RF-IATROGENIC-AZATHIOPRINE-LONGTERM- PREVENTION). When a patient is on those therapies, all three RFs fire — engine routes to PreventionPlan with deduplication; the iatrogenic RFs carry their own surveillance pr...

Used By

Indications

IND-CROHN-SPECIFIC-CANCER-PREVENTION-OBSERVATION - IND-CROHN-SPECIFIC-CANCER-PREVENTION-OBSERVATION
IND-CROHN-SPECIFIC-CANCER-PREVENTION-VIGILANCE - IND-CROHN-SPECIFIC-CANCER-PREVENTION-VIGILANCE

Sources

SRC-BEAUGERIE-CESAME-2013 - Risk of new or recurrent cancer in patients with inflammatory bowel disease and previous...