Active carcinoid syndrome in a patient with metastatic or unresectable GI-NET (or other s...

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

ID	`RF-NET-CARCINOID-SYNDROME`
Type	Red flag
Status	reviewed 2026-05-03 \| pending_clinical_signoff
Diseases	`DIS-GI-NET` `DIS-PNET`
Sources	`SRC-CLARINET-CAPLIN-2014` `SRC-NCCN-NET-2025`

Red Flag Origin

Definition	Active carcinoid syndrome in a patient with metastatic or unresectable GI-NET (or other serotonin-secreting NET). Defined clinically by any of: episodic flushing, secretory diarrhea (≥4 loose stools/day), bronchoconstriction, or elevated 24h urinary 5-HIAA / serum serotonin. Carcinoid syndrome mandates SSA therapy for symptom control regardless of antiproliferative intent; SSA is also the antiproliferative standard (CLARINET, PROMID).
Clinical direction	intensify
Category	other
Shifts algorithm	ALGO-GI-NET-ADVANCED-1L

Trigger Logic

{
  "any_of": [
    {
      "finding": "carcinoid_syndrome",
      "value": "true"
    },
    {
      "comparator": "present",
      "finding": "flushing_episodes"
    },
    {
      "comparator": "present",
      "finding": "5hiaa_elevated"
    },
    {
      "comparator": ">=",
      "finding": "diarrhea_grade",
      "threshold": 2
    }
  ],
  "type": "clinical"
}

Notes

Reverted to draft: true pending second source (SRC-ESMO-NET-2024 or similar) per §6.1 two-reviewer quality gate. Currently only cites SRC-NCCN-NET-2025. Carcinoid syndrome hallmarks: episodic cutaneous flushing (serotonin + bradykinin), diarrhea (serotonin, prostaglandins), bronchoconstriction, carcinoid heart disease (Hedinger syndrome — right-sided valvular fibrosis from chronic serotonin exposure). Biochemical confirmation: 24h urinary 5-HIAA >50 µmol/day (normal: <30). SSA reduces 5-HIAA ~50% and controls symptoms in ~70% initially. SSA dose escalation (octreotide short-acting rescue; lanreotide dose increase) and addition of telotristat ethyl (tryptophan hydroxylase inhibitor) for refractory diarrhea. Carcinoid crisis risk during surgery / embolisation — SSA IV cover required. Carcinoid heart disease: echocardiogram at baseline + annually; surgery for severe tricuspid/pulmonary regurgitation if fit.

Used By

Algorithms

ALGO-GI-NET-ADVANCED-1L - ALGO-GI-NET-ADVANCED-1L