LAUSR

detection included imaging alone (42%), imaging combined with tumor markers (39%), and tumor markers alone (7.4%). LDH was elevated in 26 (15%) cases at relapse, and like in seminoma, never in isolation as the sole indicator of relapse. Among non-relapsing NSGCT patients diagnosed between January 2000 and August 2019 (n[311), 233 (75%) registered at least one false positive LDH, and 160 (52%) recorded multiple false positive LDH values. This translates into an average of 2.9 false positives per patient journey through surveillance. CONCLUSIONS: As a marker of testis cancer relapse, LDH did not independently contribute to early relapse detection in stage I seminoma or NSGCT. False positive values were documented in a high proportion of NSGCT with no disease relapse. Based on these results we advocate no longer measuring LDH in stage I surveillance protocols.