High-dose chemotherapy with autologous stem cell transplant (HDCT) for patients (pts) with advanced germ-cell tumors (aGCT): Real-world evidence from a tertiary cancer center in Brazil.

414 Background: HDCT is a potentially curative treatment for pts with aGCT after conventional-dose chemotherapy (CDC). There is scarce evidence of outcomes from aGCT pts treated with HDCT in low and middle-income countries. Methods: We reviewed our institutional database to identify pts with progressive aGCT referred for HDCT following tumor boards. Medical charts were analyzed to extract clinical data. Log-rank was used to compare survival estimates and Cox proportional hazard to determine effects on overall survival (OS). Exploratory correlation and survival trend analysis used synthetic minority oversampling and Spearman’s rho estimated correlations. Results: From 1/2013 to 8/2022, 35 aGCT pts were referred for HDCT. Median age was 28 years (IQR 25-30). Most pts had testicular primary (84%), non-seminoma histology (87%), 1 prior treatment line (62%), poor-risk by IGCCCG (78%), and intermediate to very high-risk by IPFSG (45%). Of these, 32 pts were deemed eligible after initial evaluation, 25 had mobilization chemotherapy, and 21 received ≥1 cycle of HDCT. Reasons for treatment non-fulfillment included progressive disease and/or performance deterioration due to toxicity. HDCT regimen varied, with most pts receiving TI-CE (62%). Most pts had delays ≥1 month (85%) and ≥2 months (52%) in the scheduled treatment. The 1-year and 2-year OS rates were 42% and 38% in the eligible population, while 70% and 62% among those who had ≥ 1 cycle HDCT. No risk factors correlated with OS in the univariate analysis (Table). Exploratory analysis of oversampled pts treated with ≥1 cycle of HDCT showed correlation of poor IGCCCG (p<0.01) and IPFSG (p=0.03) with OS. Time to mobilization (TTM) was larger in poor-risk IGCCCG pts (0.4 vs. 1.7 months, p<0.01). Four deaths were attributed to HDCT. Conclusions: HDCT was feasible at our tertiary center in Brazil, despite some treatment-related deaths. For pts who had at least 1 HDCT cycle, survival outcomes were similar to the established literature. Significant delays in protocol were noted and correlated with prognostic group risk. [Table: see text]