DETECTION-2 feasibility: A feasibility trial to assess recruitment rates and ctDNA reporting times for patients with resected stage IIB/IIC/IIIA melanoma

After surgery for early-stage melanoma, most patients are cured—but a small number will see their cancer return and spread. This trial tests whether a simple blood test for circulating tumour DNA (ctDNA) can catch that relapse earlier than scans can, and spare the majority of patients from a year of unnecessary drug treatment and its side effects. Why this matters: Right now, patients with stage IIB–IIIA melanoma face a difficult choice after surgery: close monitoring or a full year of immunotherapy. The monitoring option risks missing a relapse until it is visible on imaging; the treatment option exposes many patients to side effects they may never need. ctDNA testing could tip the balance, identifying the few patients whose cancer is truly active and letting the rest avoid treatment. Potential impact: If this feasibility trial shows that ctDNA monitoring is practical—with acceptable recruitment rates and fast enough reporting times—it could reshape post-surgery care for thousands of melanoma patients each year. Instead of treating everyone, clinicians would treat only those whose blood test signals a relapse, reducing drug costs and side-effect burdens while still catching recurrences early.