Tandem High-Dose Chemotherapy and Autologous Stem Cell Transplantation for Relapsed and Refractory Germ Cell Tumors: A Single-Center Experience

Background: High-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) is an established salvage therapy for relapsed or refractory (R/R) germ cell tumors (GCTs). Methods: We conducted a retrospective analysis of 9 patients (23–41 years of age) with relapsed/refractory (R/R) GCTs treated according to the Swedish–Norwegian Testicular Cancer Group Clinical Protocol (SWENOTECA), at the Specialized Hospital for Active Treatment of Hematological Diseases (SHATHD) in Sofia, Bulgaria. The study evaluates the efficacy and safety of HDCT followed by ASCT in R/R GCTs eligible for second-line consolidation. The cohort was predominantly high-risk, with 77.7% of patients exhibiting stable or progressive disease (SD/PD) after first-line platinum therapy. Response was assessed via RECIST 1.1 criteria and tumor marker monitoring. Results: Median OS and PFS were 8.4 and 5.9 months, respectively. While the ORR post-ASCT was 33.3% (all CR), the 2-year survival plateau (33.3%) suggests curative potential in a subset of patients. Notably, there was no treatment-related mortality (TRM). Conclusions: Tandem HDCT is a feasible salvage strategy with manageable toxicity and no TRM in this small, heavily pre-treated cohort. Although efficacy results are exploratory due to the limited number of patients, the observed long-term remissions confirm the curative potential of this standard-of-care consolidation in a real-world clinical setting.