ideasIdea
FAPI PET as the workup for MCED positives
When a blood test says 'cancer signal, origin unclear', a FAPI PET scan may find it where FDG cannot.
A significant share of MCED-positive patients have no cancer found on standard imaging, creating anxiety and cost. FAPI PET has higher sensitivity than FDG in pancreatic, gastric, low-grade, and peritoneal disease, exactly the cancers MCED promises to catch.
Confidence
20%–45%likelyOnCo editors (initial estimate), 2026-09-07 · Both components exist; nobody has run the diagnostic study.
Hypothesis
FAPI PET/CT increases the cancer detection rate and reduces time to diagnosis in MCED-positive, FDG-negative or tissue-of-origin-uncertain patients.
Rationale
Complementary biology (stroma vs glucose); FAPI has low background in liver, brain, and bowel.
What would test it
Prospective diagnostic study nested in a Galleri deployment (e.g., NHS or PATHFINDER-like) randomising FDG vs FAPI PET as first-line workup.
Maturity
speculative