Interim data from SWOG S1823/GCC suggest microRNA-371a-3p (miR371) can predict relapse risk in early-stage germ cell malignancy under active surveillance, though the study authors emphasize that the clinical utility question remains open. The prospective cohort is designed to test whether miR371 measured by real-time PCR adds actionable predictive information. Investigators report relapse risk estimates by stratification groups, including a low-risk cohort primarily consisting of stage I seminoma with key favorable features and a moderate-risk group that includes lymphovascular invasion–positive nonseminoma. Serial plasma sampling occurs at 12-month or six-month intervals, up to three years or until relapse. The readout is positioned as an evidence step toward clarifying whether miR371 can support surveillance decision-making, rather than just confirming retrospective signals.