Data presented at ESMO reinforced the clinical utility of circulating tumor DNA (ctDNA) to personalize postsurgical cancer care. Multiple studies showed ctDNA assays can identify minimal residual disease after surgery and thereby guide escalation or de‑escalation of adjuvant therapy in bladder and colorectal cancer settings. One trial tested a ctDNA‑guided approach to immunotherapy in muscle‑invasive bladder cancer (IMvigor011 context) and related work demonstrated that patients with negative ctDNA could safely avoid immediate adjuvant treatment. The findings increase momentum for regulatory filings and commercial rollouts of bespoke ctDNA assays, including assays seeking FDA approval. Clinicians and diagnostics companies said validated ctDNA use could shrink unnecessary toxic therapy exposure and focus resources on patients with molecular evidence of residual disease—shifting the standard of postsurgical oncology decision‑making.