The Impact of Clinical and Morphometric Parameters on Hematopoietic Engraftment Following High-Dose Chemotherapy and Autologous Stem Cell Transplantation in Germ Cell Tumors

Background: Relapsed or refractory Germ cell tumors are commonly treated with HDCT/ASCT, yet robust predictors of hematopoietic recovery are limited. Quantitative CT-based body-composition metrics are readily available in practice, but their prognostic value for post-transplant engraftment remains uncertain. We investigated whether muscle and fat indices derived from routine CT scans are associated with the pace of hematologic recovery after HDCT/ASCT Methods Retrospective single-center cohort (n=43) with relapsed/refractory GCT undergoing HDCT/ASCT. CT within ±6 months of ASCT was analyzed at L3 to derive SMI, PMI, SFA, VFA, TFA, and VFA/SFA. Primary endpoint: engraftment time post-ASCT. Univariable associations used Spearman ρ; multivariable linear regression adjusted for age, Hb, weight, and BSA evaluated independent effects. Significance: p< 0.05 Results Median hematologic engraftment duration was 12.0 days . Engraftment duration correlated positively with age and negatively with hemoglobin. In multivariable analysis, older age and lower hemoglobin independently predicted longer engraftment; body weight and BSA were not significant. Among morphometrics, only VFA/SFA associated with delayed engraftment. SMI, PMI, and TFA were not significant. As expected after HDCT, grade 4 neutropenia and thrombocytopenia occurred in all patients. Conclusions In relapsed/refractory GCT treated with HDCT/ASCT, older age and lower post-transplant hemoglobin independently predict prolonged engraftment. Beyond traditional muscle/fat areas, a higher VFA/SFA ratio—reflecting visceral adiposity—also associates with delayed recovery, suggesting fat distribution may influence hematopoietic regeneration. These variables may support pre-transplant risk stratification and individualized supportive care.