Growth and Endocrine Data in Children after Brain Tumor and Irradiation

Due to advances in therapeutic regimes of malignant brain tumors in childhood the survival rates have significantly improve over the last decades. Besides neurological problems, long-term survivors of child brain tumors are at high risk of developing irradiation induced hypothalamic-pituitary dysfunction, primary hypothyroidism and severe growth retardation due to diminished growth of the spine after craniospinal irradiation and additional hormonal deficiency. In several patients the first clinical sign of endocrine disturbance is the precocious or early puberty. Thus, the growth velocity may be normal even in spite of the presence of growth hormone deficiency which results in late diagnosis and treatment and further results in severely affected body height in adulthood. In numerous previous investigations, the frequency of endocrine defects, the relation to irradiation dose and time after the end of treatment have been documented, indicating that the growth impairment of the spine and hypothalamic deficiencies may still develop after 5-10 years or more, while in several cases the thyroid function noramlizes. These studies retrospectively analyzed the data of patients after various treatment protocols with a wide range of irradiation doses and time after the end of treatment. We recently started an endocrine and auxiological analysis of patients treated for brain tumors in our department and so far treated 18 of such patients. The aim of this study was to define the frequency and time course of growthand endocrine deficiencies in this homogenous groups of patients as defined by the rather high irradiation dose combined with chemotherapy. On the basis of these data we further aim to define a prospective protocol for auxiological and endocrine investigations. It is essential that these patients are seen by an pediatric endocrinologist from the very beginning, since our experinece showed that the correct interpretation of the growth curve requires sufficient frequency of the data on body proportions and pubertal development as a basis for the timing of endocrine testing and eventual hormonal replacement.