Eligible patients will be divided into two cohorts, those who are CD30 positive and those who are CD30 negative/unknown. Both groups will be treated similarly and in parallel but analyzed separately. CD30 status may be unknown in the unlikely case of tumor-marker-only relapse or when a fresh tumor biopsy is not feasible, and archival tumor tissue is not obtainable despite efforts to do so. These patients will be included in the CD30 negative cohort for analysis purposes, since statistically NSGCT are more likely to be CD30 negative. The number of such patients with unknown CD30 status should not exceed 5 patients.