Excellent survival in relapsed stage I testicular cancer.

Background: Two thirds of patients with germ-cell cancer (GCC) present as clinical stage I (CSI). Following orchiectomy, active surveillance (AS) has become their standard management. However, 15-50% of patients eventually relapse with metastatic disease after AS. Relapses need to be detected early in order to achieve cure and avoid overtreatment.

Methods: We retrospectively analyzed consecutive GCC patients treated at two Swiss academic centers between 2010 and 2020. Patients with stage IS and extragonadal primaries were excluded. We compared disease characteristics and survival outcomes of patients relapsed from initial CSI to patients with de novo metastatic disease. Primary endpoint was the IGCCCG category at the time of relapse. Main secondary endpoints were progression-free survival (PFS) and overall survival (OS).

Results: We identified 360 GCC patients with initial CSI and 245 de novo metastatic patients. After a median follow-up of 47 months, 81 of 360 (22.5%) CSI patients relapsed: 41 seminoma (Sem) and 40 non-seminoma (NSem) patients. All Sems relapsed in the IGCCCG good prognosis group. NSem relapsed with good 29/40 (72.5%) and intermediate 11/40 (27.5%) prognostic features; 95.1% of relapses occurred within five years post-orchiectomy. Only 3 relapsed NSem patients died from metastatic disease. Five-year OS for relapsed CSI patients was 100% for Sem and 87% (95% CI: 61-96%) for NSem patients; five-year PFS was 92% (95% CI: 77-97) and 78% (95% CI: 56-90) for Sem and NSem, respectively. When stratified by IGCCCG prognostic groups, good risk relapsed patients had a trend towards better OS and PFS as compared to de novo metastatic patients.

Conclusions: GCC patients who relapse after initial CSI can be detected early by active surveillance and have an excellent survival.