ctDNA MRD → adjuvant therapy decision
A ctDNA MRD blood test after surgery decides who gets more treatment and who is spared it.
IMvigor011: atezolizumab only in ctDNA-positive bladder cancer patients, OS HR 0.59, approved 2026. DYNAMIC: ctDNA-negative colon cancer patients safely skip chemotherapy. Being tested in TNBC (post-KEYNOTE-522 residual disease), NSCLC, and breast (ZEST, c-TRAK).
After bladder removal, a blood test can now tell who needs immunotherapy and who can safely be spared it. This is the model for MRD-guided adjuvant therapy across cancers: treat the blood-positive, watch the blood-negative.
For stage II colon cancer, where most patients are cured by surgery alone, a blood test can identify the minority who benefit from chemotherapy and spare everyone else its side effects. It does not yet prove that treating ctDNA-positive patients improves survival compared with not treating them.