Counting MRD trials by cancer type tells you where the field is working. Counting only the interventional ones — where MRD is embedded in the intervention protocol rather than collected observationally for later analysis — gets you closer to how near each cancer is to making MRD a standard of care. These are different questions.

The bars below show both. Dark = interventional study type; light = observational. The maturity score combines interventional share with Phase 3 presence — a rough proxy for “how far is this cancer from MRD-guided therapy as standard practice?” Interventional study type is a signal that the assay sits inside a treatment protocol, not proof that an MRD result by itself directs the treatment decision.

What this tells us

Colorectal is the furthest along. It has the only solid-tumor recruiting Phase 3 trial in which ctDNA-MRD positivity triggers treatment intensification — which is why it carries the Phase 3 bonus in the maturity score and tops the solid-tumor list. For assay companies, colorectal adjuvant therapy is the solid-tumor setting closest to a reimbursable, labeled clinical indication for ctDNA-based MRD.

Lung and breast are the next tier — both still pre-Phase-3. Each has real interventional MRD activity, but neither yet has a recruiting Phase 3 in which MRD directs treatment, so both sit behind colorectal’s milestone. Between the two, the bar order simply reflects whichever currently has the higher interventional share — and that can flip as trials update, so read it as a snapshot, not a settled clinical-depth ranking. The field is still working out which settings (neoadjuvant, adjuvant, recurrence monitoring) fit; expect solid-tumor Phase 3 trials beyond colorectal over the next two to three years.

The hematology baseline matters for commercial sizing. Hematologic MRD is overwhelmingly interventional — the mature, “fully embedded” end state. Solid tumors, at 71% interventional (shown above), are roughly halfway there; closing that gap is the commercial opportunity.