Endocrine late effects after total body irradiation in patients who received hematopoietic cell transplantation during childhood: a retrospective study from a single institution.

Purpose: To evaluate the effects of total body irradiation (TBI) on the endocrine system in adults treated with hematopoietic cell transplantation (HCT) during childhood.
Methods: We studied 40 patients who underwent HCT between 1988 and 2004, mainly for childhood cancer. In 23 patients, the conditioning regimen consisted of high-dose chemotherapy and TBI (TBI+). In the other 17 patients, who did not receive TBI (TBI-), HCT was performed after high-dose chemotherapy alone.
Results: Overall, 34% of patients in the TBI+ group showed growth hormone deficiency, compared with none of the patients in the TBI- group (P < 0.05). Leydig cell failure was found in 23% of patients in the TBI+ group and in 0% of the patients in the TBI- group. Elevated FSH levels, suggesting spermatogenesis damage, were found in all the patients receiving TBI and in 36% of the patients in the TBI- group (P < 0.001). Also, primary hypothyroidism was more common in TBI+ (34%) than in TBI- (5.8%) patients (P < 0.05).
Conclusions: Our data indicate that endocrine late effects after HCT are more frequent in patients who received TBI, an observation that should be considered, even if the choice of the conditioning regimen is determined by the underlying condition in most cases.