Endocrine disorders following treatment of childhood brain tumours

Hypothalamic-pituitary dysfunction after irradiation of nonpituitary brain tumors in adults

CONTEXT

Hypothalamic-pituitary (HP) dysfunction is common in children treated with cranial radiotherapy (RT) for brain tumors, but there is little known about the risk of HP dysfunction in adults treated with RT for primary nonpituitary brain tumors.

OBJECTIVE

The objective was to study the frequency of HP dysfunction in adults after RT for nonpituitary brain tumors.

METHOD

We studied 56 adult patients who received external beam RT for primary nonpituitary brain tumors at time intervals of 12-150 months after RT. The control group consisted of 20 RT-naive patients with primary brain tumors. GH and adrenal axes were assessed using the insulin tolerance test or the glucagon stimulation test. Gonadotroph, thyrotroph, and lactotroph function were assessed using baseline blood measurements. The biological effective dose (BED) to the HP axis was calculated in the RT patients.

RESULTS

Hypopituitarism was present in 41% of patients. The frequency of GH, ACTH, gonadotropin, and TSH deficiencies, and hyperprolactinemia was 32, 21, 27, 9, and 32%, respectively. Any degree of hypopituitarism and GH deficiency was significantly associated with longer time interval from RT and greater BED. However, gonadotropin deficiency and hyperprolactinemia were only related to BED, whereas ACTH deficiency was only significantly associated with the time interval from RT. One RT-naive patient was GH deficient.

CONCLUSION

Adult patients treated with cranial irradiation for primary nonpituitary brain tumors are at high risk of hypopituitarism, which is time and dose dependent. Long-term surveillance and periodic evaluation are needed. We recommend that adult late effect clinics, similar to those for children, should be established.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of the treatment of childhood cancers. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic agents and radiation therapy. This article reviews hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteopenia-osteoporosis and obesity.

Absence of adrenocorticotropin (ACTH) neurosecretory dysfunction but increased cortisol concentrations and production rates in ACTH-replete adult cancer survivors after cranial irradiation for nonpituitary brain tumors

CONTEXT

For the first time, physiological cortisol secretion has been studied in ACTH-replete adult cancer survivors to explore any discrepancy between stimulated (during insulin-induced hypoglycemia) and spontaneous cortisol secretion and, in particular, the possible existence of ACTH neurosecretory dysfunction that might explain the excessive fatigue suffered by some cancer survivors.

STUDY SUBJECTS

Cortisol profiling at 20-min intervals over 24 h during the fed state was undertaken in 34 patients (10 females), aged 17-53.7 yr (median, 21.5 yr), 2-29 yr (median, 11.5 yr) after receiving conventional cranial irradiation for nonpituitary brain tumors or leukemia (n = 5) and in 33 age-, gender-, and body mass index-matched normal controls, of whom 23 patients and 17 controls were also profiled in the last 24 h of a 33-h fast.

RESULTS

The fed profile mean cortisol concentration (mean +/- sem) was significantly increased (by 14%) in the patients compared with that in normal subjects (213 +/- 6.9 vs. 187 +/- 6.7 nmol/liter; P = 0.009), with all individual values above the lowest seen in normal subjects. Multiparameter deconvolution analysis revealed a parallel increase (by 20%) in cortisol secretion rates (1.8 +/- 0.09 vs. 1.5 +/- 0.08 nmol/liter.min; P = 0.03) due to selective augmentation of the cortisol mass released per burst with no changes in burst frequency (12/24 h) or half-life. No significant differences were observed between males and females, after short-term fasting, or between female patients and normal females. Thus, in the light of total group comparisons, male patients had even higher values than normal males, and more so during fasting (mean cortisol and cortisol secretion increased by 20 and 29% in the fed state and by 41 and 32% in the fasting state, respectively; P < 0.05).

CONCLUSIONS

This study has demonstrated that radiation-induced ACTH neurosecretory dysfunction does not exist and, thus, resolved the clinical dilemma as to whether cortisol replacement should be considered in those patients with excessive fatigue and normal stimulated cortisol responses. On the contrary, cranial irradiation causes activation of the corticotrope-adrenal axis, and in the absence of ACTH deficiency, this activation is manifested by parallel increases in circulating cortisol levels and cortisol production rates without any change in cortisol half-life. The lack of cortisol increase in female patients may be attributed to the adverse effect of their higher body mass index on cortisol secretion or may reflect a genuine gender dichotomy.

Neuropsychological performance and quality of life of 10 year survivors of childhood medulloblastoma

PURPOSE

Survivors of medulloblastoma, the most frequently occurring malignant brain tumor of childhood, suffer neuropsychological damage in the first decade after diagnosis. Cognitive performance, psychosocial functioning and quality of life were assessed in medulloblastoma survivors in the second decade after diagnosis.

METHODS

Ten year survivors were evaluated with a battery of neuropsychological tests, and self-report questionnaires regarding quality of life and emotional functioning. Clinical variables examined included the patient's age at diagnosis, duration since diagnosis, treatment, and complications.

RESULTS

Sixteen medulloblastoma survivors [mean age at diagnosis: 7.2 years, range: 1-15 years; 6 males] were tested at a mean age of 22.2 years [range: 13.6-27.9 years]. All survivors had been treated with craniospinal radiation therapy; nine were treated with chemotherapy. Significant impairments were identified in more than 50 of survivors on tests within all neuropsychological domains, including attention, memory, visuospatial abilities, motor functioning, language, and executive functioning. Significant impairments were also identified in all psychosocial domains examined, including employment, ability to drive an automobile, participation in normal education, independent living, and dating history. Most importantly, quality of life scores, reported by both survivors and their caretakers, were in the normal range.

CONCLUSION

Survivors of childhood medulloblastoma frequently suffer severe persistent deficits in a wide-range of neuropsychological functional domains. Nevertheless, survivors and their families do not report impaired quality of life. These severe neuropsychological and psychosocial deficiencies justify further attempts to reduce or delay the use of craniospinal radiation therapy for childhood medulloblastoma.

Hypopituitarism as a consequence of brain tumours and radiotherapy

Radiation-induced damage to the hypothalamic-pituitary (h-p) axis is associated with a wide spectrum of subtle and frank abnormalities in anterior pituitary hormones secretion. The frequency, rapidity of onset and the severity of these abnormalities correlate with the total radiation dose delivered to the h-p axis, as well as the fraction size, younger age at irradiation, prior pituitary compromise by tumour and/or surgery and the length of follow up. Whilst, the hypothalamus is the primary site of radiation-induced damage, secondary pituitary atrophy evolves with time due to impaired secretion of hypothalamic trophic factors and/or time-dependent direct radiation-induced damage. Selective radiosensitivity in the neuroendocrine axes with the GH axis being the most vulnerable to radiation damage accounts for the high frequency of GH deficiency, which usually occurs in isolation following irradiation of the h-p axis with doses less than 30 Gy. With higher radiation doses (30-50 Gy), however, the frequency of GH insufficiency substantially increases and can be as high as 50-100%, and TSH and ACTH deficiency start to occur with a long-term cumulative frequency of 3-6%. Abnormalities in gonadotrophin secretion are dose-dependent; precocious puberty can occur after radiation dose less than 30 Gy in girls only, and in both sexes equally with a radiation dose of 30-50 Gy. Gonadotrophin deficiency occurs infrequently and is usually a long-term complication following a minimum radiation dose of 30 Gy. Hyperprolactinemia, due to hypothalamic damage leading to reduced dopamine release, has been described in both sexes and all ages but is mostly seen in young women after intensive irradiation and is usually subclinical. A much higher incidence of gonadotrophin, ACTH and TSH deficiencies (30-60% after 10 years) occur after more intensive irradiation (>70 Gy) used for nasopharyngeal carcinomas and tumours of the skull base and following conventional irradiation (30-50 Gy) for pituitary tumours. Radiation-induced anterior pituitary hormone deficiencies are irreversible and progressive. Regular testing is mandatory to ensure timely diagnosis and early hormone replacement therapy to improve linear growth and prevent short stature in children cured from cancer, and in adults preserve sexual function, prevent ill health and osteoporosis and improve the quality of life.

Pediatric brain tumors

Brain tumors in children vary with regard to histology, location, gender distribution, and age of onset. The past several decades have witnessed substantial improvements in the diagnosis and treatment. As a result, the number of long-term survivors also has increased continuously. Recent advances in neuroimaging facilitate tumor localization and mapping of brain function by noninvasive techniques and are becoming important in preoperative assessment for brain tumors. Surgery remains the mainstay of treatment of many tumor types. A role for chemotherapy is emerging, particularly for nonresectable tumors and in infants, for whom the adverse effects of radiation therapy are severe. Despite the improved treatments and prognostic data, however, many long-term survivors experience significant neurocognitive and developmental deficits.

Final height and body mass index among adult survivors of childhood brain cancer: childhood cancer survivor study

The objectives of this study were 1) to compare final height and body mass index (BMI) between adult survivors of childhood brain cancer and age- and sex-matched population norms, 2) to quantify the effects of treatment- and cancer-related factors on the risk of final height below the 10th percentile (adult short stature) or having a BMI of 30 kg/m(2) or more (obesity). Treatment records were abstracted and surveys completed by 921 adults aged 20-45 yr who were treated for brain cancer as children and were participants in the multicenter Childhood Cancer Survivor Study. Nearly 40% of childhood brain cancer survivors were below the 10th percentile for height. The strongest risk factors for adult short stature were young age at diagnosis and radiation treatment involving the hypothalamic-pituitary axis (HPA). The multivariate odds ratio for adult short stature among those 4 yr of age or younger at diagnosis, relative to ages 10-20 yr, was 5.67 (95% confidence interval, 3.6-8.9). HPA radiation exposure increased the risk of adult short stature in a dose-response fashion (trend test, P < 0.0001). Adjuvant chemotherapy was not an independent risk factor for adult short stature. BMI distribution in survivors did not differ appreciably from that of population norms; however, in females, young age at diagnosis and HPA radiation dose (trend test, P < 0.001) were associated with risk of obesity. Except for patients treated with surgery only, survivors of childhood brain cancer are at very high risk for adult short stature, and this risk increases with radiation dose involving the HPA. We did not find a corresponding elevated risk for obesity.

Hypothalamo-pituitary-adrenal axis integrity after cranial irradiation for childhood posterior fossa tumours

BACKGROUND

The evolution of anterior pituitary deficits after treatment for pituitary tumours has been largely attributed to local irradiation, but may be influenced as much by tumour mass or surgery. Other than growth hormone (GH) insufficiency, the late endocrinopathies after survival from non-central brain tumours have been little documented. The aim of this study was to investigate the hypothalamic-pituitary-adrenal (HPA) axis in long-term survivors of cranial irradiation for childhood posterior fossa tumours.

PROCEDURE

We studied long-term data in patients treated prepubertally for posterior fossa brain tumours and systematically referred by radiation oncologists for growth and pubertal monitoring to the London Centre for Paediatric Endocrinology over the last 25 years. They must have undergone HPA axis assessment twice, first prepubertally at documentation of growth failure, and second at completion of growth and puberty. Data on sixteen patients (12 males, 4 females; median age: 5.7 years, range: 2.5-8.8 years), who had undergone excision surgery with high dose cranial irradiation and/or chemotherapy for childhood posterior fossa tumours, were examined. Patients were followed for a median of 11.0 (range: 6.8-21.4) years after radiotherapy. HPA axis assessment was undertaken with the insulin-induced hypoglycaemia test (ITT). Basal thyroid, cortisol and gonadal function tests were undertaken annually throughout the follow-up period and any deficits replaced.

RESULTS

At each ITT, all patients mounted an inadequate GH response. By the end of the follow-up period all patients remained severely GH deficient, two (12.5%) had partial ACTH insufficiency, one (6.3%) had secondary hypothyroidism but none were gonadotropin deficient or hyperprolactinaemic.

CONCLUSIONS

Unlike the severe, evolving multiple pituitary deficits after treatment of pituitary or central tumours in adults, these findings in children with posterior fossa tumours suggest that, with the exception of GH, neurotoxicity due to irradiation per se is associated with a low prevalence of anterior pituitary hormone deficiencies, even at a long follow-up. Since the children in this study were selected for assessment on the basis of growth failure, the high prevalence of GH insufficiency at first testing is to be expected; however, the early onset (within 1-3 years of irradiation) and permanence we have identified supports the view that GH is the most sensitive hormone to radiation injury.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of childhood cancers and their treatments. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic drugs and radiation therapy. This article will explore the current literature about endocrine late effects of hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteoporosis and obesity.

Endocrine and cardiovascular late effects among adult survivors of childhood brain tumors: Childhood Cancer Survivor Study

BACKGROUND

Survivors of childhood brain tumors (CBTs) are at high risk for a variety of late adverse effects. Most research on long-term effects of CBTs has been comprised of single-institution case series without comparison groups. Research on CBT late effects often is focused on neurologic and sensory outcomes, with less emphasis on other potential targets such as the endocrine and circulatory systems. The current study was conducted to contrast the incidence of endocrine and cardiovascular conditions among CBT survivors as a function of treatment and to determine the risk of occurrence of these conditions relative to a sibling comparison group.

METHODS

As part of the Childhood Cancer Survivor Study (CCSS), treatment data were collected from medical records and self-reported late effects were ascertained from a survey questionnaire of 1,607 CBT patients who survived their disease for 5 or more years. For comparison purposes, questionnaire data were also collected from 3418 randomly selected siblings of participants in CCSS.

RESULTS

One or more endocrine conditions were reported by 43% of CBT survivors. Compared with siblings, CBT survivors had a significantly increased risk of late-onset (>/= 5 years postdiagnosis) hypothyroidism (relative risk [RR] = 14.3; 95% confidence interval [95% CI] 9.7-21.0), growth hormone deficiency (RR = 277.8; 95% CI 111.1-694.9), the need for medications to induce puberty (RR = 86.1; 95% CI 31.1-238.2), and osteoporosis (RR = 24.7; 95% CI 9.9-61.4). One or more cardiovascular conditions were reported by 18% of CBT survivors, with an elevated late-onset risk for stroke (RR = 42.8; 95% CI 16.7-109.8), blood clots (RR = 5.7; 95% CI 3.2-10.0), and angina-like symptoms (RR = 2.0; 95% CI 1.5-2.7). Very few late effects were evident among those treated with surgery only, but risks were consistently elevated for those treated with radiation and surgery, and higher still for those who also received adjuvant chemotherapy.

CONCLUSIONS

Childhood brain tumor survivors are at a significantly increased risk for several adverse endocrine and cardiovascular late effects, particularly if they were treated with radiation and chemotherapy. Lifetime medical surveillance and follow-up for potential toxicities are necessary because treatment-related complications may occur many years after therapy.

Neurological evaluation of children and adolescents with brain tumor, based on ambulatory-oriented follow-up

Taken as proved that brain tumors are the second most frequent childhood neoplasm - only outnumbered by leukemias - we have undertaken a clinical perspective study with seventy brain tumor patients ranging from one to fifteen years of age, throughout a four-year period (1993-1997), based on ambulatory-oriented follow-up. Forty-one male and twenty-nine female patients were analyzed, in that a slightly higher number of infratentorial tumors was observed (thirty-eight cases), compared to those supratentorially located (thirty-two cases). The most repeatedly observed during the study was the medulloblastoma (twenty-one patients), followed by the astrocytoma (fifteen patients) and the germinoma (eleven patients). It should be pointed out that during the ambulatory follow-up 75,5% of patients developed neurological sequels. A tumor recurrence was noticed in 34,3% of them, while 21,4% eventually died.

Growth hormone and segmental growth in survivors of head and neck embryonal rhabdomyosarcoma

AIMS

To assess the impact of treatment for embryonal rhabdomyosarcoma on spinal growth and limb length and examine the response of these parameters to growth hormone (GH) treatment.

METHODS

We conducted a retrospective case note review of 17 survivors of head and neck rhabdomyosarcoma followed up at a single institution. All children had been treated with chemotherapy and local radiotherapy. Growth velocity, height, sitting height, and subischial limb length SDS scores were analysed.

RESULTS

Growth failure secondary to isolated GH deficiency (GHD) developed in 7/17 patients. GHD occurred at a median (range) of 3.4 (1.3-9.9) years after radiotherapy tumour doses of 46 (40-50) Gy. Growth velocity, height, and subischial limb length SDS were significantly reduced in the GHD group and improved with GH therapy.

CONCLUSIONS

GH treatment resulted in a significant improvement in sitting height SDS. We discuss the unexpected improvement in spinal growth in survivors with GHD.

Cranial radiotherapy of childhood brain tumours: growth hormone deficiency and its relation to the biological effective dose of irradiation in a large population based study

OBJECTIVE

The study was to determine the incidence of GH deficiency (GHD) following cranial radiotherapy (RT) for a childhood brain tumour in a large population based study and analyse the biological effective dose (BED) to the hypothalamus/pituitary (HP) region as a risk factor.

DESIGN

BED was assessed by use of the linear-quadratic (LQ) model, which gives a means of expressing the biological effect of various treatment schedules in a uniform way. In patients aged >/= 18 years (n = 53) GH status was assessed by an insulin-tolerance test (ITT) (n = 34), however, in patients with seizure disorders (n = 19), and in 20 children aged < 18 years GH status was assessed by an arginine test. Cut-off levels for GHD, indicating GH substitution, were defined by a peak GH response of < 9 mU/l and < 15 mU/l for patients >/= 18 and < 18 years, respectively.

PATIENTS

Ninety-one children aged < 15 years eligible for the study, diagnosed between 1970 and 1997 in the Eastern part of Denmark, the Faroe Islands and Greenland, with a primary brain tumour not directly involving the HP axis. 84% (n = 76) agreed to participate. Three patients were excluded due to hypothyroidism detected at time of testing.

MEASUREMENTS

Serum GH and levels of serum insulin-like growth factor-I (s-IGF-I) and serum insulin-like growth factor binding protein-3 (s-IGFBP-3) were measured. BED was assessed to the HP region.

RESULTS

The median age at the time of RT was 8.7 years (range: 0.8-14.9 years) and the median time of follow-up was 15 years (range: 2-28 years). Fifty-eight patients (80%) had GHD and they had received a median BED of 77.5 Gy to the HP region, whereas the median BED was 54.5 Gy for 15 patients without GHD (P = 0.002). Peak GH and BED were correlated (rs = -0.53, P < 0001). Median IGF-I SDS and IGFBP-3 SDS were -2.5 (-5.2-0.7 SDS) and -1.7 (-5.8-0.9 SDS), respectively, and IGF-I SDS was correlated to peak GH (rs = 0.45, P < 0.001). Peak GH and length of follow-up were related (rs = -0.28, P = 0.018). Stepwise backward multiple linear regression analysis showed that the best-fit model to predict the peak GH release following ITT/arginine stimulation included BED (P < 0.0001) and length of follow-up (P = 0.05).

CONCLUSIONS

The data of this study suggest that the majority of long-term survivors of brain tumours develop GH deficiency following radiotherapy in childhood and that the adverse effects of radiotherapy may be directly related to the biologically effective dose. With longer follow-up fewer patients might respond normally to GH stimulation tests.

Endocrine dysfunctions in patients treated for brain tumors: incidence and guidelines for management

Endocrine alterations are frequently found in patients undergoing treatment for CNS tumors. Careful follow-up aimed at the early detection of recurrences, with life-long monitor of hypothalamus-pituitary (HP) function, will also reveal any endocrine dysfunctions; indeed, their appropriate diagnosis and treatment may determine a significant improvement in the quality of life of these patients.

Insulin-like growth factor-I and insulin-like growth factor binding protein-3 during maintenance chemotherapy of acute lymphoblastic leukemia in children

PURPOSE

To assess the effect of maintenance chemotherapy (MT) on growth factors and growth in children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Twenty-one children (10 girls, 11 boys) with standard risk pre-B ALL treated with chemotherapy had serum insulin-like growth factor-I (IGF-I), serum IGF binding protein-3 (IGFBP-3) levels, and linear growth and weight data measured every 3 months during MT. The levels of the cytotoxic metabolites of methotrexate (MTX) and 6-mercaptopurine (6MP) (i.e., erythrocyte MTX polyglutamates [E-MTX], and erythrocyte 6-thioguanine nucleotides [E-6TGN]), s-aminotransferases, and white blood counts (WBC) were measured at least monthly.

RESULTS

At the beginning of MT, the median IGF-I standard deviation scores (SDS) and IGFBP-3 SDS were -0.52 and -0.09, respectively, which declined during MT to -1.67 (P < 0.001) and -1.82 (P < 0.001), respectively. At the time of diagnosis, the median height SDS was -0.4, which declined during MT to a median height SDS of -0.9 at cessation of therapy. No significant correlations were found between growth factor levels, growth and body mass index (BMI) versus the doses of MTX, and 6MP, E-MTX, E-6TGN, s-aminotransferases, or WBC.

CONCLUSIONS

A significant decline in IGF-I, IGFBP-3, and growth retardation may not be directly related to the treatment intensity during MT.

The role of surgery in pediatric gliomas

Pediatric glial tumors differ from adult gliomas in several ways that are of major therapeutic importance. First, the value of extensive tumor resection, which is controversial for malignant intrinsic brain tumors in adults, has been confirmed for a variety of childhood brain tumors, such as supratentorial high-grade and low-grade gliomas and infratentorial low-grade gliomas, ependymomas, and some medulloblastomas. Second, chemotherapy has been found to be effective in improving overall outcome in several childhood brain tumors, such as medulloblastoma and supratentorial high-grade glioma, but has yet to be proven to have a major benefit for adult tumors. In addition, chemotherapy is increasingly used to delay or avoid radiotherapy in young children with high-grade and incompletely resected low-grade tumors to avoid the morbidity of irradiation on the developing nervous system. Third, the prognosis for histologically similar tumors is often more favorable in children than adults. The present chapter will highlight the unique features of childhood glial tumors, discuss general principles in the clinical presentation, diagnostic evaluation, and treatment of these tumors, and then focus on the surgical management and outcome of the more common types of tumors.

Pediatric brain tumors

Pediatric brain tumors differ from adult brain tumors in several major ways. First, the types of tumors encountered in children are uncommon in adults, and vice versa. Second, tumors of the posterior fossa comprise a far greater percentage of tumors in children as compared to adults. Third, the value of extensive tumor resection, which is controversial for malignant brain tumors in adults, has been confirmed for a variety of childhood brain tumors. Fourth, chemotherapy has been shown to be effective in improving overall outcome in several childhood brain tumors, but has yet to be demonstrated to have a major benefit for adult tumors. In addition, to avoid the morbidity of irradiation on the developing nervous system, chemotherapy is increasingly used to delay or avoid using radiotherapy in children younger than 3 years of age with high-grade and incompletely resected low-grade tumors. Fifth, the prognosis for histologically similar tumors is often more favorable in children than adults. A review of general principles in the clinical presentation, diagnostic evaluation, and treatment of childhood brain tumors is followed by discussion of surgical management, adjuvant therapy, and outcome of the more common types of tumors.

[Primary pediatric tumours of the central nervous system. Anatomopathological study of 623 cases]

Tumours of central nervous system (CNS) represent the second most frequent malignancy in children under 15 years of age but are the commonest cause of death. The authors present the epidemiologic and histopathologic analysis of 623 primary tumours of CNS occurring during the period 1990 to 1996 in paediatric patients. In this period 3318 biopsies of CNS were analyzed. In this total were included 623 paediatric tumours (18 7%). The age of patients ranged from 5 months to 15 years, 325 tumours occurred in males and 298 in females. The majority affected the posterior fossa. The majority of paediatric neoplasias were of glial origin (n = 277). The most frequent tumours were: astrocytoma (27.9%), medulloblastoma (9.95%), craniopharyngioma (5.93%), ependymoma (4.97%) and glioblastoma (3.37%).

Testing the hypothalamic-pituitary-adrenal axis in survivors of childhood brain and skull-based tumors

The objective of this study was to determine whether a low dose of ACTH (0.2 microg/kg) improves the sensitivity of ACTH testing in detecting hypothalamic-pituitary-adrenal (HPA) axis abnormalities in survivors of childhood brain and skull-based tumors. Twenty-two children who had undergone treatment for brain or skull-based tumors were enrolled in a prospective study to extensively evaluate the HPA axis. Five tests of the adrenal axis were evaluated in each patient, including determination of basal serum cortisol, a standard ACTH test (250-microg i.v. bolus), a low dose ACTH test (0.2 microg/kg i.v. bolus), an insulin tolerance test, and a single dose metyrapone test. Cortisol responses to both ACTH tests were nearly identical. Two patients (9%) failed the low dose ACTH test, whereas three (14%) failed the standard ACTH test; five of the children (23%) failed the insulin tolerance test, and five (23%) had abnormal responses to metyrapone. One child who initially passed the metyrapone test failed the test 19 months later after becoming symptomatic. All children with abnormal metyrapone test results had low levels of basal cortisol secretion. In this study, the low dose ACTH test did not improve the sensitivity of ACTH testing for evaluation of the HPA axis. We conclude that a single morning basal cortisol level is a good screen for testing the HPA axis in children. We recommend confirming HPA axis dysfunction with the single dose metyrapone test, although this test also has limitations.

Neurofibromatosis 1 and 2

Neurofibromatosis (NF) 1 and 2 are multisystem disorders associated with a variety of neoplastic and non-neoplastic manifestations that typically progress in severity during the lifetime of the affected patient. The importance of appropriately diagnosing these disorders stems from the fact that the natural history of an associated neoplasm, such as a peripheral nerve tumor or an optic glioma, may be significantly different depending on whether or not the lesion arises in a person with NF. In addition, the indications for therapeutic intervention, hierarchy of treatment options and long-term management goals may differ substantially for patients with NF-related versus sporadic tumors. Finally, recognition of the diagnosis comprises an essential step for providing appropriate multidisciplinary evaluation and counseling to affected patients and their families. This article addresses the principal manifestations of these disorders and provides a contemporary review of the diagnostic and therapeutic issues that arise in children with NF1 and NF2.

Growth hormone treatment in irradiated children with brain tumors

We assessed the efficacy of GH treatment in 25 GH deficient patients irradiated for brain tumors (eight with glioma cranio-irradiated, eleven with medulloblastoma and six with ependymoma craniospinal-irradiated). We administered GH at doses of 0.6-0.9 IU/kg/week for one to three years at least two years after diagnosis of the tumor. We assessed the efficacy of the treatment each year by comparing the values of height velocity over bone age and change in the ratios progression of chronological age/progression of bone age and progression of statural age/progression of bone age. The treatment promoted satisfactory growth; better results were obtained in patients with glioma, who received cranial irradiation only, than in those with medulloblastoma or ependymoma, who received spinal irradiation as well. Moreover, the growth prognosis improved, especially in the cranio-irradiated patients. In our series of patients four presented tumor recurrence; these results did not differ significantly from those in irradiated patients with cerebral tumors who were not treated with GH.

School behaviour and health status after central nervous system tumours in childhood

This study was designed to assess the overall morbidity burden of survival from central nervous system (CNS) tumours and its impact on return to a normal lifestyle. School behaviour and health status of 27 children after treatment for CNS tumours, of 25 of their school-aged siblings, plus age- and sex-matched controls is reported. Spinetta school behaviour, Lansky play-performance and Health Utilities Index (mark II and III) assessments have been made. Patients had reduced mobility and increased pain levels. They demonstrated a reluctance to participate in organized physical activities. Impaired cognition, emotion and self-esteem were reported. They worried more than controls but attended school willingly, interacted normally with their peers and viewed the future confidently. Their siblings were reluctant to express openly concern for others or feelings of joy. Teachers were reliable proxies for most attributes, notable exceptions being speech and emotion. This is the first study to have assessed the school behaviour of a cohort solely composed of survivors of childhood CNS tumours. The good social reintegration is reassuring and likely to reflect a high level of psychosocial support. However, the results presented identify these young people as a 'special educational needs' group as defined by the 1981 and 1993 Education Acts.

Special issues in the management of gliomas in children with neurofibromatosis 1

Neurofibromatosis 1 (NF1) is a common multisystem disorder that is frequently associated with neoplastic and non-neoplastic lesions within the central nervous system. Improvements in neuroimaging have led to increased detection of both types of lesions. Focal areas of increased T2 signal represent the most common abnormalities detected. The vast majority of such lesions are non-neoplastic and fluctuate in number and size during childhood. Optic pathway tumors are second in frequency and generally manifest an indolent natural history, although some lesions will increase in size over time and lead to progressive visual impairment. A smaller percentage of patients will develop gliomas within the cerebral and cerebellar hemispheres of brain-stem. This article will review areas of controversy in the evaluation and follow-up of patients with NF1 and will present our approach to these issues. We will also discuss therapeutic considerations in these patients that take into account the unique features of the underlying disorder.

Intracranial ependymomas of childhood: long-term outcome and prognostic factors

A detailed outcome analysis was performed on 40 children with intracranial ependymomas treated at our institution between 1975 and 1993 to identify those factors that were predictive of overall and progression-free survival. Three patients (7.5%) who were treated in the first 5 years of the study died within 3 months of surgery and were excluded from further outcome assessments. Eight (22%) of the 37 patients who survived the perioperative period had evidence of leptomeningeal dissemination at presentation, on the basis of either imaging (three children) and/or cytological (six children) results. The 5- and 10-year progression-free survival rates among these 37 patients were 45.1 and 36.1%, respectively; overall survival rates were 57.1 and 45.0%, respectively. The site of progression was local in 17 of 19 patients with progressive disease. Three factors were found to have a significant association (P < or = 0.05) with the outcome on both univariate and multivariate analyses: 1) the extent of the resection, 2) the age of the patient at diagnosis, and 3) the duration of the symptoms before diagnosis. The 5-year progression-free and overall survivals were 8.9 and 22%, respectively, among patients who had evidence of residual disease on postoperative imaging studies, compared with 68 and 80% rates among patients with no apparent residual disease (P = 0.0001 and P < 0.0001, respectively). Patients younger than 3 years fared significantly worse than older children (5-year progression-free and overall survival rates of 12 and 22%, respectively, in the younger children versus 60 and 75% in older children (P = 0.003 and P = 0.01, respectively). In addition, patients with a duration of symptoms before diagnosis of < 1 month had a worse outcome than those with a more protracted course (5-year progression-free and overall survival rates of 33 and 33%, respectively, versus rates of 53 and 64%, respectively (P = 0.02 for both). Neither the finding of evidence for dissemination at presentation nor the detection of anaplastic histological features (e.g., dense cellularity or high numbers of mitoses) were associated with a significantly worse outcome in this series. The combination of variables that had the strongest association with both favorable and unfavorable outcomes was the combination of the age of the patient and the resection extent. Only 2 of 17 patients older than 3 years with gross total resections have died, whereas 13 of 20 children who were either younger than 3 years or had radiologically incomplete resections have died (P < 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

Long-term neurobehavioral outcome in pediatric brain-tumor patients: review and methodological critique

This paper provides an overview of pediatric brain tumors and reviews the literature on long-term neurobehavioral outcomes for these children. Progress in this area has been slow due to numerous methodological and practical complications. While some general conclusions can be drawn, the development of comprehensive models awaits more research into the multiplicity of biological and nonbiological events, and their interactions, potentially affecting outcome. Increased theoretical and methodological sophistication will be needed to address this complex classification of diseases. Barriers to research in this area are enumerated as are suggestions for future efforts.