Endocrine late effects in survivors of infantile acute lymphoblastic leukemia

Infantile acute lymphoblastic leukemia (ALL) is a rare disease. In survivors, endocrine late effects, such as growth disorder and hypothyroidism, have been reported, but gonadal function remains unclear. Infantile ALL frequently requires transplantation and higher doses of alkylating agents, even in the absence of transplantation. Some studies in childhood cancer survivors reported that a cyclophosphamide equivalent dose (CED) of > 20 g/m² was associated with testosterone deficiency in boys and > 8 g/m² with ovarian dysfunction in girls. We retrospectively reviewed the treatment and endocrine function of 6 infantile ALL survivors treated at our hospital using their medical records. The patients' age at the time of the study was between 12 and 26 yr. One patient had 0 transplant, four of them had 1 transplant, and one had 2 transplants, with CEDs of 3, 9-11, and 24 g/m² respectively. Two patients had short stature, and two patients experienced hypothyroidism. All three girls with a CED of 9-11 g/m² had primary hypogonadism, and the boy with a CED of 24 g/m² had high LH and FSH levels, suggesting testosterone deficiency and spermatogenesis disorders. In conclusion, gonadal function, growth and thyroid function should be carefully monitored in infantile ALL, and CED may be useful for predicting the development of hypogonadism.