skip to main content

Choi Criteria GIST — SCE Medical Oncology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateGI CancersChoi Criteria GISTSCE Medical Oncology

A 65-year-old man with a gastrointestinal stromal tumour (GIST) on imatinib has stable disease. His oncologist uses the Choi criteria for response assessment rather than RECIST. Why?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Choi criteria assess both tumour SIZE and DENSITY (Hounsfield units on CT) — GISTs often respond to imatinib by becoming hypodense (necrotic/cystic) without significant size reduction; RECIST would miss these responses and underestimate treatment benefit

GIST response to imatinib frequently manifests as decreased CT density (necrosis/cystic degeneration) without proportional size reduction. RECIST (size-only criteria) misses these responses. Choi criteria define response as: ≥10% decrease in tumour size OR ≥15% decrease in tumour density (HU) on contrast-enhanced CT. The Choi criteria have superior correlation with time to progression and disease-specific survival compared with RECIST in GIST. PET-CT can also assess metabolic response (FDG uptake decrease) very early after imatinib initiation.

Reference: ESMO 2024 GIST; Choi et al JCO 2007