Disturbance of pubertal development after cancer treatment.

Chemotherapy and irradiation to the hypothalamic-pituitary-gonadal axis given for childhood cancer carry with them a risk of endocrine late effects. These treatment modalities are part of the treatment of common oncological diseases in childhood such as acute lymphoblastic leukaemia, brain tumours, Hodgkins lymphoma and solid tumours outside the central nervous system. Cranial irradiation of a prepubertal child can induce early or even precocious puberty, particularly in girls. Hypogonadotrophic hypogonadism may develop at a later stage. Irradiation of the gonads, as e.g. part of total body irradiation before bone marrow transplantation, will most likely cause gonadal failure and late, incomplete or absent puberty in girls. Many boys will experience a normal pubertal development except for small testes. Alkylating agents given for a variety of childhood cancers, are gonadotoxic. After high doses of these drugs, girls are at great risk of developing ovarian failure, whereas boys will usually go through puberty normally. Many children receive a combination of several treatment modalities, which complicates the prediction of pubertal development. Control and management of children with cancer at risk of having a disturbance of puberty is difficult and requires detailed knowledge of endocrinology as well as oncology. This chapter reviews the common treatments for the most frequent childhood cancers, the known effects of the therapy on pubertal development and provides outlines of control and management.