Adult testicular volume predicts spermatogenetic recovery after allogeneic HSCT in childhood and adolescence

Background Testicular dysfunction and infertility are of major concern in long‐term survivors after allogeneic hematopoietic stem cell transplantation (HSCT). This study assesses predictive factors for very long‐term testicular recovery after allogeneic HSCT in childhood and adolescence. Procedure Testicular volume, sperm production and long‐term need of testosterone substitution were evaluated among 106 male survivors transplanted at Huddinge and Helsinki University Hospitals from 1978 through 2000, at a mean age of 8 ± 4.6 years (range 1–17). A mean ± SD of 13 ± 4.8 years (range 4–28) had elapsed since their HSCT and the mean age of the participants was 22 ± 6.0 years (range 12–42). An adult testicular volume was recorded in 74 patients at a mean age of 19 ± 3.3 years (range 14–36). Results Recipients conditioned with busulfan‐based regimens or regimens containing only cyclophosphamide had significantly larger adult testicular volumes (mean volume 18 ml and 16 ml vs. 9 ml, P