Spinal irradiation impairs the osteo-anabolic effects of low-dose GH replacement in adults with childhood-onset GH deficiency

Endocrine sequelae beyond 10 years in survivors of medulloblastoma

INTRODUCTION

Survival following treatment of paediatric medulloblastomas has significantly improved over the past few decades, but as a consequence, late effects, particularly endocrine sequelae, have been recognized. The complete picture of late effects, however, has been limited by short duration of follow-up.

AIM

To establish the evolution of endocrine sequelae in patients treated for medulloblastoma.

METHODS

Single-centre analysis of medulloblastoma treatment and endocrine sequelae in patients diagnosed between 1982 and 2002.

RESULTS

A total of 109 patients were treated for medulloblastoma, with various treatment modalities involving radio- and chemotherapy. Only 45 (41%) patients remained alive, and details of treatment and late effects were available for 35 (25 m). The median age at diagnosis was 8 (range 2-14) years, and the median follow-up was 18 (range 10-28) years. Growth hormone deficiency (GHD) was the most prevalent hormone deficiency (97%), followed by primary hypothyroidism (60%) and adrenocorticotrophic hormone (ACTH) deficiency (45·5%). The median time from end of treatment to loss of growth hormone was 1·7 (range 0·7-15) years, ACTH deficiency 2·9 (range 0·75-7·5) years and hypothyroidism 4·1 (range 0·7-11·4) years. Twenty-three percentage developed hypogonadism (17% primary and 6% secondary), whilst precocious puberty was seen in 20%. Endocrinopathies appeared to be more prevalent in those treated with concomitant chemotherapy and radiotherapy.

CONCLUSIONS

Prevalence of endocrine sequelae in medulloblastoma survivors is high, and evolution of endocrine dysfunction can occur as late as 15 years from treatment completion; hence, long-term close monitoring of growth, puberty and gonadal function is essential.

Radiotherapy-induced hypopituitarism: a review

Hypopituitarism is a disorder caused by impaired hormonal secretions from the hypothalamic-pituitary axis. Radiotherapy is the most common cause of iatrogenic hypopituitarism. The hypothalamic-pituitary axis inadvertently gets irradiated in patients receiving prophylactic cranial radiotherapy for leukemia, total body irradiation and radiotherapy for intracranial, base skull, sinonasal and nasopharyngeal tumors. Radiation-induced hypopituitarism (RIH) is insidious, progressive and largely nonreversible. Mostly, RIH involves one hypothalamic-pituitary axis; however, multiple hormonal axes deficiency starts developing at higher doses. Although the clinical effects of the hypopituitarism are more profound in children and young adults, its implications in older adults are being increasingly recognized. The risk continues to persist or increase up to 10 years following radiation exposure. The clinical management of hypopituitarism is challenging both for the patients and healthcare providers. Here we have reviewed the scale of the problem, the risk factors and the management of RIH.

Is the treatment for childhood solid tumors associated with lower bone mass than that for leukemia and Hodgkin disease?

BACKGROUND

Cancer disease and its therapy (e.g., chemotherapeutic agents such as glucocorticoids, methotrexate, antymetabolities, cranial and local irradiation) may severely disturb normal growth, bone mineral acquisition, and skeletal development because most individuals go through the stages of rapid growth when childhood cancer is diagnosed.

PROCEDURES

To identify factors associated with reduced bone mineral density (BMD) in survivors of childhood cancer the authors examined 114 patients (70 males) who had been treated for acute lymphoblastic leukemia (ALL; n = 43), Hodgkin disease (HD; n = 35), and solid tumors (ST; n = 36) twice. Median age at diagnosis was 8.4 years; at the consecutive examinations it was 12.8 and 16.3 years, respectively. To assess bone density we used dual-energy x-ray absorptiometry (DXA).

RESULTS

In the first examination, patients with a history of steroid therapy had higher total and spine BMD and higher BMI (body mass index) than those who were not given steroids. At the end of the follow-up, no differences were found in BMD between subgroups, although BMI was still higher in both ALL and HD patients than in those with ST.

CONCLUSIONS

Patients treated for solid tumors have reduced bone mass. Low BMI and local irradiation seem to be the factors responsible for reduced BMD in children treated for ST. The use of steroids does not disturb bone mass accumulation in patients treated for childhood malignancies. However, a long-term effect of cancer treatment on osteoporosis risk remains to be determined.

Adult growth hormone replacement therapy and neuroimaging surveillance in brain tumour survivors

OBJECTIVE

Systematic collections of neuroimaging data are nonexistent in brain tumour survivors treated with adult growth hormone replacement therapy (AGHRT). We present our surveillance data.

DESIGN

In 1993, our unit implemented a policy of performing brain scans on every brain tumour survivor before starting AGHRT, with repeat neuroimaging at least once after 12-18 months' treatment. Reports for baseline scans and most recent scans were analysed for this retrospective study.

PATIENTS

All brain tumour survivors who received AGHRT (60 patients) were included in the analysis.

MEASUREMENTS

Evidence and extent of residual tumour, tumour progression, tumour recurrence, and secondary neoplasms (SN) on baseline scan and latest follow-up scan.

RESULTS

All patients had baseline scans performed. Follow-up scans were available in 41/45 (91%) patients who received AGHRT for more than 1 year (mean duration +/- SD of GHRT was 6.7 +/- 3.6 years). Sixteen patients had residual tumours, and SNs (all meningiomas) were demonstrated in three patients on baseline scans. Appearances remained stable in 34 (83%) patients during follow-up (extending to 17.4 +/- 8.3 years after tumour diagnosis). Of the 16 residual primary tumours, an incurable ependymoma continued to grow, and one meningioma progressed slightly in size over 7.7 years. Follow-up scans also revealed continued growth of the SNs detected at baseline, and five additional meningiomas (two in patients with a previous SN, confirming an excess risk in this subgroup, P = 0.02). All SNs occurred on average 22.8 (range 17-37) years after radiotherapy.

CONCLUSIONS

Our data do not suggest an increased rate of recurrence or progression of childhood brain tumours during AGHRT. Nonetheless, vigilance and long-term surveillance are needed in these patients in order to detect and monitor SNs, in particular in patients with a previous history of a SN. We endorse a proactive neuroimaging policy, preferably as part of a larger, controlled trial in the future.

Bone density in survivors of childhood cancer

Advances in combination chemotherapy, radiation therapy, surgery, and bone marrow transplantation have resulted in markedly improved survival rates for many children with cancer. Advancements in therapy, however, have led to new concerns, namely long-term consequences of effective treatments. Young adult and adult survivors of childhood cancer are at risk for a number of disorders related to therapy. Specifically, the young adult who has survived cancer, attendant treatments, and their complications is at risk for factors that can lead to suboptimal acquisition of peak bone mass. These factors include chronic illness, nutritional deficiencies, limited physical activity, and treatment with glucocorticoids, multiagent chemotherapy, and radiation. The long-term adverse effects of these therapies on endocrine systems, especially sex steroid and growth hormone deficiencies, are additional risk factors for some patients. After a brief review of the processes associated with acquisition of peak bone mass in the young adult, this article examines the impact of cancer and cancer therapy on bone mineral density in survivors of childhood cancer.

Growth hormone replacement therapy (GHRT) in children and adolescents: skeletal impact

In addition to its well-established effects on linear growth in childhood and adolescence, growth hormone has both direct and indirect actions on bone remodelling and homeostasis. In this review the limitations of methods of assessment of bone mineral density are highlighted. The influence of growth hormone deficiency of childhood-onset, on bone mineral accretion and, the specific skeletal implications of GHD in long-term survivors of childhood cancers, are discussed. Specific influential factors, which affect peak bone mass achievement and therefore skeletal health in later life, are evaluated.

Childhood-onset growth hormone (GH) deficiency in adult life

Over the last decade GH replacement therapy for adults has progressed in status from research study to a mainstream clinical indication. An area ripe for further research, however, is the difference between adults who developed GHD before and after completion of growth and puberty. That differences exist, not only in aetiology, but also in phenotype and response to GH therapy is clear. However, whether these differences are intrinsic to the timing of onset of GHD, or related to secondary factors including the method of assessment or dose of GH employed is uncertain. This chapter discusses the current state of knowledge in this area and poses further questions, not only for the researcher attempting to understand the mechanisms underlying these differences, but also for the physician seeking to ameliorate the impact of GHD in patients who acquired GHD in childhood.