Despite advances in early-stage lung cancer treatment, a significant number of patients experience disease recurrence after surgery or initial therapy. A study has now demonstrated that a blood test (liquid biopsy) can reliably detect lingering lung cancer traces even in the earliest clinical stages, long before a tumor is large enough to show up on a scan. This real-time genetic monitoring detailed in an article appearing in The Journal of Molecular Diagnostics, accurately predicts relapse risk, opening a window for timely, personalized therapeutic interventions.