Long-term effects of cranial irradiation on endocrine function in children with brain tumors. A prospective study

Endocrine Late Effects in Childhood Cancer Survivors

Simple Summary

Recent advances in cancer treatment have led to improved survival, with an exponential increase in sequelae among survivors. Around 50% of survivors will experience at least one hormonal disorder, with radiotherapy, hematopoietic stem cell transplantation, and alkylating chemotherapy being the most frequently related. Therefore, lifelong monitoring of childhood cancer survivors at risk is paramount. With this review, we describe in detail the most prevalent endocrine sequelae, considering new approaches such as proton beam therapy and immune-related endocrinopathies with the advent of precision oncology treatment. We hope to encourage oncologists and endocrinologists to develop early detection guidelines that minimize sequelae and have a positive impact on their quality of life.

Abstract

Childhood cancer management has improved considerably over the years, leading to a significant improvement in survival of up to 80%. However, childhood cancer survivors are at the highest risk of developing sequelae resulting from treatment, with endocrine complications being frequently observed among survivors. Multiple predisposing factors for endocrine sequelae have been identified, including age at diagnosis, treatment received, radiation, tumor type, and genetic polymorphisms, which could explain the individual predisposition to develop drug toxicity. Novel agents targeting tumor growth and immune checkpoint inhibitors have recently become the cornerstone for the treatment of different cancers, triggering a myriad of immune-related endocrinopathies. Endocrine sequelae of cancer therapy will have an impact on not only childhood but also on the survival and quality of life of these highly complex patients. Therefore, lifelong monitoring of childhood cancer survivors at risk of endocrine diseases is paramount. Encouraging oncologists and endocrinologists to develop new follow-up and early detection guidelines that minimize sequelae among these patients has become a priority, promoting integration between pediatric and adult units since many sequelae may manifest only after years to decades of follow-up.

Neuroprotection of Radiosensitive Juvenile Mice by Ultra-High Dose Rate FLASH Irradiation

Major advances in high precision treatment delivery and imaging have greatly improved the tolerance of radiotherapy (RT); however, the selective sparing of normal tissue and the reduction of neurocognitive side effects from radiation-induced toxicities remain significant problems for pediatric patients with brain tumors. While the overall survival of pediatric patients afflicted with medulloblastoma (MB), the most common type primary brain cancer in children, remains high (≥80%), lifelong neurotoxic side-effects are commonplace and adversely impact patients’ quality of life. To circumvent these clinical complications, we have investigated the capability of ultra-high dose rate FLASH-radiotherapy (FLASH-RT) to protect the radiosensitive juvenile mouse brain from normal tissue toxicities. Compared to conventional dose rate (CONV) irradiation, FLASH-RT was found to ameliorate radiation-induced cognitive dysfunction in multiple independent behavioral paradigms, preserve developing and mature neurons, minimize microgliosis and limit the reduction of the plasmatic level of growth hormone. The protective “FLASH effect” was pronounced, especially since a similar whole brain dose of 8 Gy delivered with CONV-RT caused marked reductions in multiple indices of behavioral performance (objects in updated location, novel object recognition, fear extinction, light-dark box, social interaction), reductions in the number of immature (doublecortin⁺) and mature (NeuN⁺) neurons and increased neuroinflammation, adverse effects that were not found with FLASH-RT. Our data point to a potentially innovative treatment modality that is able to spare, if not prevent, many of the side effects associated with long-term treatment that disrupt the long-term cognitive and emotional well-being of medulloblastoma survivors.

Late Effects of Parasellar Lesion Treatment: Hypogonadism and Infertility

Central hypogonadism, also defined as hypogonadotropic hypogonadism, is a recognized complication of hypothalamic-pituitary-gonadal axis damage following treatment of sellar and parasellar masses. In addition to radiotherapy and surgery, CTLA4-blocking antibodies and alkylating agents such as temozolomide can also lead to hypogonadism, through different mechanisms. Central hypogonadism in boys and girls may lead to pubertal delay or arrest, impairing full development of the genitalia and secondary sexual characteristics. Alternatively, cranial irradiation or ectopic hormone production may instead cause early puberty, affecting hypothalamic control of the gonadostat. Given the reproductive risks, discussion of fertility preservation options and referral to reproductive specialists before treatment is essential. Steroid hormone replacement can interfere with other replacement therapies and may require specific dose adjustments. Adequate gonadotropin stimulation therapy may enable patients to restore gametogenesis and conceive spontaneously. When assisted reproductive technology is needed, protocols must be tailored to account for possible long-term gonadotropin insufficiency prior to stimulation. The aim of this review was to provide an overview of the risk factors for hypogonadism and infertility in patients treated for parasellar lesions and to give a summary of the current recommendations for management and follow-up of these dysfunctions in such patients. We have also briefly summarized evidence on the physiological role of pituitary hormones during pregnancy, focusing on the management of pituitary deficiencies.

The impact of childhood cancer and its treatment on puberty and subsequent hypothalamic pituitary and gonadal function, in both boys and girls

Childhood cancer survivors (CCS) are at an increased risk of endocrine disorders. Disorders of the hypothalamic-pituitary-gonadal (HPG) axis are a particular concern because of their impact on pubertal development and future fertility and may be of central (hypothalamic or pituitary damage) or primary (gonadal) origin. Hypogonadism may present as pubertal disorders during adolescence and subsequent infertility in adulthood but should be anticipated to ensure appropriate surveillance is in place to address these issues at an appropriate age. Those at risk of HPG axis dysfunction include those with tumours primarily affecting the hypothalamus, pituitary or gonads themselves or due to their treatment with surgery, radiotherapy and chemotherapy. CCS who have had cranial irradiation of more than 30 Gy are at risk of gonadotrophin deficiency. Those who have had gonadotoxic chemotherapy, especially alkylating agents or radiotherapy to the gonads are at risk of primary gonadal failure. HSCT survivors who have had chemotherapy and total body irradiation are at risk of primary gonadal failure but may also have gonadotrophin deficiency. Understanding those at risk is essential to appropriate counselling and long-term follow-up. This chapter gives an overview on the impact of childhood cancer and its treatment on puberty, gonadal function and fertility in childhood cancer survivors.

Radiations and female fertility

Hundreds of thousands of young women are diagnosed with cancer each year, and due to recent advances in screening programs, diagnostic methods and treatment options, survival rates have significantly improved. Radiation therapy plays an important role in cancer treatment and in some cases it constitutes the first therapy proposed to the patient. However, ionizing radiations have a gonadotoxic action with long-term effects that include ovarian insufficiency, pubertal arrest and subsequent infertility. Cranial irradiation may lead to disruption of the hypothalamic-pituitary-gonadal axis, with consequent dysregulation of the normal hormonal secretion. The uterus might be damaged by radiotherapy, as well. In fact, exposure to radiation during childhood leads to altered uterine vascularization, decreased uterine volume and elasticity, myometrial fibrosis and necrosis, endometrial atrophy and insufficiency. As radiations have a relevant impact on reproductive potential, fertility preservation procedures should be carried out before and/or during anticancer treatments. Fertility preservation strategies have been employed for some years now and have recently been diversified thanks to advances in reproductive biology. Aim of this paper is to give an overview of the various effects of radiotherapy on female reproductive function and to describe the current fertility preservation options.

Endocrine sequelae in childhood cancer survivors

Thanks to the advances in cancer treatment, the five-year survival rate after childhood cancer has increased up to 80%. Therefore 1/500 young adults will be a survivor. Endocrine sequelae are most common, affecting 40-60% of survivors. The most frequent sequelae include growth failure and gonadal and thyroid diseases. Sequelae occur more frequently in survivors from central nervous system tumors, leukemia, and lymphoma. Their development will depend on the type of cancer, its location, age at diagnosis, and treatment administered. Treatments associated to more endocrine sequels are cranial radiotherapy and hematopoietic cell transplantation. Because of the high prevalence of endocrine sequelae, international guidelines recommend endocrinologists to prospectively evaluate the survivors. As some of these endocrine changes will not develop until adult life, transition programs should be implemented, and active investigation should be made to decrease the endocrine consequences of cancer treatment.

Health conditions associated with metabolic syndrome after cancer at a young age: A nationwide register-based study

PURPOSE

Childhood cancer survivors are at risk for developing metabolic syndrome (MetS), which subsequently leads to cardiovascular morbidity and excess mortality. Our aim was to investigate the purchases of medications associated with MetS among 7551 early onset cancer patients compared to siblings.

METHODS

Our nationwide Finnish population-based registry study analyzed the drug purchase of medication among early onset cancer patients diagnosed with cancer below the age of 35 years between 1994 and 2004 compared to siblings by linkage to the drug purchase registry, allowing for a maximal follow-up of 18 years.

RESULTS

The hazard ratios (HRs) for purchasing antihypertensives and diabetes drugs were higher after both childhood (HR 4.6, 95%CI 3.1-7.0; HR 3.0, 95%1.5-6.1) and young adulthood (YA) cancer (HR 1.5, 95%CI 1.3-1.8; HR 1.6, 95%CI 1.1-2.2) compared to siblings. The HRs for purchasing lipid-lowering drugs were elevated both after childhood (HR 4.3,95%CI 0.9-19.5) and YA cancer (HR 1.6, 95%CI 1.04-2.5), but only reached significance in YA cancer patients. Among specific cancer diagnosis groups, highest HR values for antihypertensives were found in childhood acute lymphoblastic leukemia (ALL) (HR 6.1, 95%CI 3.7-10.3) and bone tumor (HR 4.3, 95%CI 1.9-9.4), and YA ALL (HR 4.8, 95%CI 3.1-7.0) and acute myeloid leukemia (AML) (HR 3.4, 95%CI 2.5-5.1) patients. Moreover, childhood ALL (HR 6.3, 95%CI 2.7-14.8), AML (HR 7.6, 95%CI 1.9-24.5) and central nervous system (CNS)-tumor (HR 3.5, 95%CI 1.3-9.2) and YA ALL (HR 3.7, 95%CI 1.2-9.5) patients showed the strongest likelihood of purchasing diabetes drugs compared to siblings.

CONCLUSION

The purchase of medications associated with MetS was increased after early onset cancer and highly dependent on the age at cancer diagnosis and the cancer diagnosis. Prevention strategies are imperative for reducing potentially life-threatening cardiovascular complications after early onset cancer.

Effect of cancer treatment on hypothalamic-pituitary function

The past 30 years have seen a great improvement in survival of children and young adults treated for cancer. Cancer treatment can put patients at risk of health problems that can develop many years later, most commonly affecting the endocrine system. Patients treated with cranial radiotherapy often develop dysfunction of the hypothalamic-pituitary axis. A characteristic pattern of hormone deficiencies develops over several years. Growth hormone is disrupted most often, followed by gonadal, adrenal, and thyroid hormones, leading to abnormal growth and puberty in children, and affecting general wellbeing and fertility in adults. The severity and rate of development of hypopituitarism is determined by the dose of radiotherapy delivered to the hypothalamic-pituitary axis. Individual growth hormone deficiencies can develop after a dose as low as 10 Gy, whereas multiple hormone deficiencies are common after 60 Gy. New techniques in radiotherapy aim to reduce the effect on the hypothalamic-pituitary axis by minimising the dose received. Patients taking cytotoxic drugs do not often develop overt hypopituitarism, although the effect of radiotherapy might be enhanced. The exception is adrenal insufficiency caused by glucocorticosteroids which, although transient, can be life-threatening. New biological drugs to treat cancer can cause autoimmune hypophysitis and hypopituitarism; therefore, oncologists and endocrinologists should be vigilant and work together to optimise patient outcomes.

High prevalence of early hypothalamic-pituitary damage in childhood brain tumor survivors: need for standardized follow-up programs

INTRODUCTION

Childhood brain tumor survivors (CBTS) are at increased risk to develop endocrine disorders. Alerted by two cases who experienced delay in diagnosis of endocrine deficiencies within the first 5 years after brain tumor diagnosis, our aim was to investigate the current screening strategy and the prevalence of endocrine disorders in survivors of a childhood brain tumor outside of the hypothalamic-pituitary region, within the first 5 years after diagnosis.

PROCEDURES

Firstly, we performed a retrospective study of 47 CBTS treated in our center, diagnosed between 2008 and 2012. Secondly, the literature was reviewed for the prevalence of endocrine disorders in CBTS within the first 5 years after diagnosis.

RESULTS

Of 47 CBTS eligible for evaluation, in 34% no endocrine parameters had been documented at all during follow up. In the other 66%, endocrine parameters had been inconsistently checked, with different parameters at different time intervals. In 19% of patients an endocrine disorder was found. At literature review 22 studies were identified. The most common reported endocrine disorder within the first 5 years after diagnosis was growth hormone deficiency (13-100%), followed by primary gonadal dysfunction (0-91%) central hypothyroidism (0-67%) and primary/subclinical hypothyroidism (range 0-64%).

CONCLUSION

Endocrine disorders are frequently seen within the first 5 years after diagnosis of a childhood brain tumor outside of the hypothalamic-pituitary region. Inconsistent endocrine follow up leads to unnecessary delay in diagnosis and treatment. Endocrine care for this specific population should be improved and standardized. Therefore, high-quality studies and evidence based guidelines are warranted.

[Endocrinological outcome in children and adolescents survivors of central nervous system tumours after a 5 year follow-up]

INTRODUCTION

Given the successful increase in survival rates with the current treatments for central nervous system tumours (CNST), survivors are at high risk for late adverse effects.

PURPOSE

To evaluate the endocrine sequelae in children with CNST according to the type of tumour and treatment received.

PATIENTS AND METHODS

A retrospective review of the clinical features, auxology, hormone determinations and imaging findings of 38 patients (36.8% females, 63.2% males) with CNST, with a minimum of 5 years follow-up, was performed.

RESULTS

The mean age at diagnosis was 5.34 ± 3.07 years, with 76.3% of the patients having at least one hormone deficiency, of which growth hormone (GH) (73.7% of all patients) was the most prevalent, followed by thyrotropin (TSH) (68.4%), corticotropin (31.6%), antidiuretic hormone (28.9%), and gonadotropin (LH/FSH) (21.1%) deficiency. Precocious puberty was found in 21.1% of patients. After 5 years of follow-up, 28.9% were obese. Craniopharyngioma had more hormone deficiencies, obesity and recurrence rates. The most frequently administered treatment was surgery + chemotherapy + radiotherapy, in 47.4% of the patients. Mean final height (20 patients) was -1.2 1.6 SDS, with a mean difference of -0.53 SDS regarding their target height.

CONCLUSIONS

1) The type of tumour and treatment received influence the endocrinological sequelae. 2) The most frequent hormone deficiencies in all types of CNST, regardless of the treatment received, were GH and TSH. 3) Early diagnosis and prompt intervention of endocrine dysfunction can reduce the morbidity and improve quality of life over the long term.

Medulloblastoma and primitive neuroectodermal tumors

Medulloblastomas and sPNETs remain highly problematic tumors to treat. Prognosis has improved over the past two decades, but many children who survive treatment have significant long-term sequelae. The improvements in outcome have been due to advances in surgical techniques, the wider use of chemotherapy, and the more judicious use of radiotherapy. For further improvements,the recent impressive discoveries concerning molecular mechanisms of embryonal tumor origin, development,and growth will need to be translated into molecularly based, risk-adapted therapy.

Pilot study on sex hormone levels and fertility in women with malignant gliomas

The standard treatment of patients with high-grade gliomas based on conformal radiation therapy (RT) with or without chemotherapy (CT) may induce endocrine deficiencies of pituitary and subsequently also of peripheral hormones. In 24 premenopausal women with high-grade gliomas treated with RT and CT, hormonal changes and their impact on quality of life were investigated. Serum concentrations of gonadal, pituitary and of thyroid hormones were measured at various time points after initial anti-neoplastic therapy. Additionally, endovaginal ultrasound was performed and patients' quality of life (QLQ) and female role functioning were assessed. Of 24 patients, 23 (96%) reported a change in their menstrual pattern. Twenty-one patients reported at least transient amenorrhoea with a mean duration of 26.1 months (3-96 months). Increased prolactin serum levels were found in 10 women, 8 of them with amenorrhoea. Thirteen women showed menopausal or perimenopausal hormone pattern, 3 a pattern compatible with hypogonadism. Changes in thyroid hormone levels were seen in 8 patients. Furthermore, patients complained about fatigue and menopausal symptoms, like flushes, weakness and gain of weight. They felt a decrease of libido combined with the loss of attractiveness as a female, and an increased need for tender care and security. The hormonal deficiencies in female patients with malignant gliomas require thorough evaluation and individualized diagnosis and sometimes intervention.

[Medulloblastomas: review]

INTRODUCTION

The term of "medulloblastoma" refers to cerebellar tumors belonging to the family of primitive neuro-ectodermic tumors (PNET). Medulloblastomas represent 40% of cerebellar tumors, 15 to 20% of brain tumors and the first cause of malignant brain tumors in childhood. Seventy to 80% of cases are diagnosed in children versus 20 to 30% in adults.

UPDATED KNOWLEDGE

Diagnosis is based on clinical and radiological exams, and proved on pathological analysis in association with molecular biology. Treatment comprises surgery, craniospinal radiotherapy except for children under five years of age and chemotherapy according to age and high-risk criteria. Medulloblastoma is a rare case of a central nervous system tumor which is radio- and chemo-sensitive. Treatment goals are, on one hand, to improve the survival rates and, on the other hand, to avoid late neurocognitive, neuroendocrine and orthopedic side effects related to radiation therapy, notably in children. The prognosis is relatively good, with a five year survival rate over 75% after complete resection of a localized tumor although sequelae may still compromise outcome.

PERSPECTIVES AND CONCLUSION

Management of patients with medulloblastoma implies a multidisciplinary approach combining the contributions of neurosurgery, neuroradiology, pediatric oncology, neuro-oncology and radiotherapy teams.

Differential recovery of neural stem cells in the subventricular zone and dentate gyrus after ionizing radiation

Radiation therapy is a widely used treatment for malignant central nervous system tumors. Mature neurons are terminally differentiated, whereas stem and progenitor cells have a prominent proliferative capacity and are therefore highly vulnerable to irradiation. Our aim was to investigate how cranial radiation in young rats would affect stem/progenitor cells in the two niches of adult neurogenesis, the subventricular zone (SVZ) and the dentate gyrus of the hippocampal formation. Nine weeks after irradiation we found that in irradiated animals, hippocampal neurogenesis was reduced to 5% of control levels. Similarly, the numbers of actively proliferating cells and radial glia-like stem cells (nestin+/glial fibrillary acidic protein [GFAP]+) in the dentate gyrus were reduced to 10% and 15% of control levels, respectively. In the irradiated olfactory bulb, neurogenesis was reduced to 40% of control levels, and the number of actively proliferating cells in the SVZ was reduced to 53% of control levels. However, the number of nestin+/GFAP+ cells in the SVZ was unchanged compared with controls. To evaluate the immediate response to the radiation injury, we quantified the amount of proliferation in the SVZ and dentate gyrus 1 day after irradiation. We found an equal reduction in proliferating cells both in dentate gyrus and SVZ. In summary, we show an initial response to radiation injury that is similar in both brain stem cell niches. However, the long-term effects on stem cells and neurogenesis in these two areas differ significantly: the dentate gyrus is severely affected long-term, whereas the SVZ appears to recover with time.

Current treatment approaches for infants with malignant central nervous system tumors

The management of brain tumors in very young children remains a challenge for neuro-oncologists in large part because of the greater vulnerability of the developing brain to treatment-related toxicity. Nearly three decades of infant brain tumor clinical trials have led to significant progress in the delineation of prognostic factors and improvements in outcome. Innovative strategies that employ high-dose chemotherapy, intrathecal chemotherapy, modified focal irradiation, or combinations of these have been used to delay or avoid the use of conventional craniospinal irradiation in order to minimize the risk for deleterious neurocognitive impairment in survivors. However, it is difficult to evaluate the impact of such approaches on intellectual and functional outcome, and results to date are limited. This review covers the most recent therapeutic advances for the most common histological subtypes of malignant infant brain tumors: medulloblastoma, supratentorial primitive neuroectodermal tumor, ependymoma, atypical teratoid rhabdoid tumor, choroid plexus carcinoma, and high-grade glioma. Survival and neurocognitive outcome are emphasized.

Hypopituitarism following radiotherapy

Deficiencies in anterior pituitary hormones secretion ranging from subtle to complete occur following radiation damage to the hypothalamic-pituitary (h-p) axis, the severity and frequency of which correlate with the total radiation dose delivered to the h-p axis and the length of follow up. Selective radiosensitivity of the neuroendocrine axes, with the GH axis being the most vulnerable, 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%. Compensatory hyperstimulation of a partially damaged h-p axis may restore normality of spontaneous GH secretion in the context of reduced but normal stimulated responses; at its extreme, endogenous hyperstimulation may limit further stimulation by insulin-induced hypoglycaemia resulting in subnormal GH responses despite normality of spontaneous GH secretion in adults. In children, failure of the hyperstimulated partially damaged h-p axis to meet the increased demands for GH during growth and puberty may explain what has previously been described as radiation-induced GH neurosecretory dysfunction and, unlike in adults, the ITT remains the gold standard for assessing h-p functional reserve. Thyroid-stimulating hormone (TSH) and ACTH deficiency occur after intensive irradiation only (>50 Gy) 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 (>60 Gy) used for nasopharyngeal carcinomas and tumors of the skull base, and following conventional irradiation (30-50 Gy) for pituitary tumors. The frequency of hypopituitarism following stereotactic radiotherapy for pituitary tumors is mostly seen after long-term follow up and is similar to that following conventional irradiation. Radiation-induced anterior pituitary hormone deficiencies are irreversible and progressive. Regular testing is mandatory to ensure timely diagnosis and early hormone replacement therapy.

Radiation-induced hyposuppression of the hypothalamic-pituitary-adrenal axis is associated with alterations of hippocampal corticosteroid receptor expression

Therapeutic brain irradiation in children can cause a progressive decline in cognitive functions through a diminished capability to learn and memorize. Because of the known involvement of the hippocampus in memory consolidation, this study was aimed at examining the late effects of gamma radiation on hypothalamic-pituitary-adrenal (HPA) axis activity and hippocampal corticosteroid receptor expression in an animal model of cranial radiotherapy. In the late-response phase, the basal and stress-induced corticosterone levels were not affected by radiation, but the suppression of glucocorticoid negative feedback by dexamethasone was attenuated in irradiated rats. Western blot analyses showed that exposure to radiation led to a decrease of cytosolic glucocorticoid receptor (GR) levels and a concomitant elevation of mineralocorticoid receptor (MR). The results obtained were complemented by those of RT-PCR, since the ratio of GR/MR mRNA was also decreased after radiation exposure. Dexamethasone appeared to be much less effective in shifting GR to the nuclear compartment in irradiated rats than in sham-irradiated animals. However, the expression of chaperones that aid GR intracellular trafficking, Hsp90 and Hsp70, remained unaffected. In conclusion, our data suggest that the hallmark of the late response to gamma radiation is a hyposuppressive state of the HPA axis that is associated with a decrease in both the GR/MR ratio and the nuclear accumulation of dexamethasone-activated GR in the hippocampus.

The molecular biology of ependymomas

Intracranial ependymomas are the third most common primary brain tumor in the pediatric population. Although an anaplastic variant is recognized, numerous studies examining the prognostic implications of histological features, such as necrosis, endothelial proliferation and mitoses, have yielded contradictory results. In order to improve outcome prediction in affected patients and to refine therapeutic decision-making, there is a strong need for identifying relevant biological correlates of tumor behavior. The molecular biology of tumors is a rapidly expanding field and includes investigations into cytogenetics, oncogenes, growth factors, growth factor receptors, hormonal receptors, proliferation markers, apoptosis, cell cycle genes and cell adhesion molecules, as well as factors potentially related to therapeutic resistance, such as the multidrug resistance gene. The molecular biology of astrocytic tumors in adults has been the subject of many studies; however, relatively few studies have been focused on ependymomas. Herein we review potential oncological markers in ependymomas that have been identified to date and highlight the limitations of our current knowledge as a basis for defining areas for future investigation.

[Long-term care of young adults surviving childhood cancer - where do we go?]

METHODS

Between January 1990 and November 2006, 65 consecutive childhood cancer survivors entered a prospective follow-up study to evaluate the frequency and severity of tumor- and/or therapy-related long-term sequelae. Their median age at diagnosis was 9.7 years, median actual age is 25.1 years, and median duration of follow-up is 14.8 years.

RESULTS

Nine patients (13.9%) were completely free from late effects, whereas 31/65 patients (47.6%) had only minimal late effects without need of medical support and 25/65 patients (38.5%) had severe late effects requiring long-term medical care. The most frequent late effects were endocrine deficits, musculosceletal problems, neurologic problems, chronic hepatitis and hearing loss. Currently, a network of local adult care providers is being established in order to enable a smooth and competent referral from pediatric hemato-oncology to adult medicine.

CONCLUSIONS

Two thirds of former childhood cancer patients are able to return to everyday life without any impairment. However, one third is suffering from considerable morbidity requiring long-term medical care. Transition models from pediatric hemato-oncology to adult health care providers are urgently needed.

A case report of Wyburn-Mason syndrome and review of the literature

INTRODUCTION

Wyburn-Mason syndrome is a distinct congenital neurocutaneous entity comprised of ipsilateral arteriovenous malformations (AVMs) of the midbrain, vascular abnormalities affecting the visual pathway, and facial nevi.

METHODS

We report a case and review of the literature of all other reported cases of Wyburn-Mason syndrome (n = 26) in the English literature since 1973.

RESULTS

In this review, we report on a 4(1/2)-year-old boy with Wyburn-Mason syndrome who presented with left retinal and orbital AVMs and a ruptured thalamic AVM. The patient did not respond to light in the left eye and demonstrated a left afferent pupillary defect. He did not have any cutaneous lesions. We also characterize other reported cases of Wyburn-Mason syndrome.

CONCLUSION

The presentation of patients with Wyburn-Mason syndrome can vary greatly according to the site and the extent of vascular lesions. Intracranial AVMs occasionally hemorrhage with significant morbidity. Treatment is controversial, and patients are typically managed conservatively by observation.

Sensitivity of anterior pituitary hormones to irradiation

Cranial irradiation is used in the management of a diverse group of intracranial pathologies. However, if any part of the hypothalamic-pituitary axis is included in the radiation field, there is a risk of developing neuroendocrine dysfunction. Growth hormone is the most radiosensitive of the anterior pituitary hormones, followed by the gonadotropins, adrenocorticotropic hormone and thyroid-stimulating hormone. A number of factors determine both the occurrence and severity of hypothalamic-pituitary dysfunction, including: the dose of radiation received by the hypothalamic-pituitary axis (determined by a number of factors including total dose and fractionation schedule and ultimately expressed as the biological effective dose); length of time since cranial irradiation; age of the patient at the time of cranial irradiation; type of radiotherapy administered; and the different inherent radiosensitivities of the anterior pituitary hormones. These neuroendocrine abnormalities usually develop a number of years after the initial insult and, therefore, patients who have received cranial irradiation should receive annual endocrine assessments. The establishment of endocrine late-effect clinics for the survivors of childhood cancers have gone some way to addressing this problem; however, other groups of patients, particularly those receiving cranial irradiation in adult life, may not have systematic endocrine assessment.

Paediatric central nervous system tumours in a New Zealand population: A 10-year experience of epidemiology, management strategies and outcomes

We analysed 166 cases of paediatric central nervous system tumour presenting to Auckland City and Starship Children's Hospital, New Zealand, between 1995 and 2004. The purpose of this study was to perform an audit of paediatric neurosurgical practice in the upper North Island of New Zealand with the objective of assessing patient presentation, demographics, and modality and efficacy of therapy. The overall incidence of central nervous system tumours was 3.42/100,000/year. The incidence rate of medulloblastoma for Maori was over double that for European New Zealanders. Tumour clearance was attempted in 81.3% of patients. Some type of adjunct therapy was received by 45.2% of patients. Overall, 60.8% of patients had satisfactory or good results. Survival rates for pilocytic astrocytoma and ependymoma were consistent with previous studies. Survival data for medulloblastoma demonstrate improved outcomes with complete resection of tumour and with a specialist paediatric neurosurgeon compared with general neurosurgeons. Recent management changes have led to improved outcomes.

Pathophysiology of radiation-induced growth hormone deficiency: efficacy and safety of GH replacement

Radiation-induced growth hormone deficiency (GHD) is primarily due to hypothalamic damage. GH secretion by the pituitary may be affected either secondary to some degree of quantitative deprivation of hypothalamic input or, if the radiation dose is high enough, by direct pituitary damage. As a consequence, the neurosecretory profile of GH secretion in an irradiated patient remains pulsatile and qualitatively intact. The frequency of pulse generation is unaffected, but the amplitude of the GH pulses is markedly reduced. Over the last 25 years, the final heights achieved by children receiving GH replacement for radiation-induced GHD have improved; these improvements are attributable to refinements in GH dosing schedules, increased use of GnRH analogues for radiation-induced precocious puberty, and a reduced time interval between completion of irradiation and initiation of GH therapy. When retested at the completion of growth, 80-90% of these teenagers are likely to prove severely GH deficient and, therefore, will potentially benefit from GH replacement in adult life. Such long-term GH treatment in patients treated previously for a brain tumor means that critical and continuous surveillance must be devoted to the risk of tumor recurrence and the possibility of second neoplasms.

Long-term effects of radiation therapy on cognitive and endocrine function in children with leukemia and brain tumors

BACKGROUND

As the number of long-term survivors of childhood cancer has grown, it has become increasingly clear that central nervous system therapy may have serious long-term effects on cognition and endocrine function. These complications have been studied most extensively in children with brain tumors and leukemia.

REVIEW SUMMARY

Children with acute lymphoblastic leukemia previously treated with cranial irradiation are at risk for cognitive decline. Chemotherapy-only regimens, which rely on high-dose frequently administered methotrexate, are also associated with producing cognitive dysfunction. Children irradiated for brain tumors are even more vulnerable. Risk factors include perioperative morbidity, young age, large-volume high-dose cranial irradiation, supra-tentorial location of tumor, moyamoya syndrome, and leukoencephalopathy. Cognitive decline is progressive over at least a decade. The most common radiation-induced endocrinopathies are hypothyroidism and growth hormone deficiency. Treatment effects on growth are multifactorial and include growth hormone deficiency,spinal shortening, precocious puberty, undetected hypothyroidism,and poor nutrition. Fifty percent to 80% of children treated with craniospinal radiation for brain tumors will experience growth failure. In hopes of reducing neurotoxicity, current treatments limit the dose and volume of radiation while adding chemotherapy. Results have not been uniformly positive, however, and may increase toxicity in some cases.

CONCLUSIONS

The standard of care in 2004 is that children who have been treated for brain tumors and leukemia should be monitored for cognitive and endocrine dysfunction. Until effective non-neurotoxic treatment is identified, long-term effects assessments are essential to maximize the quality of life of survivors of childhood cancer.

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.

Irradiation-induced progenitor cell death in the developing brain is resistant to erythropoietin treatment and caspase inhibition

One hemisphere of postnatal day 8 (P8) rats or P10 mice was irradiated with a single dose of 4-12 Gy, and animals were killed from 2 h to 8 weeks after irradiation (IR). In the subventricular zone (SVZ) and the granular cell layer (GCL) of the dentate gyrus, harboring neural and other progenitor cells, nitrosylation and p53 peaked 2-12 h after IR, followed by markers for active caspase-3, apoptosis-inducing factor and TUNEL (6-24 h). Ki67-positive (proliferating) cells had disappeared by 12 h and partly reappeared by 7 days post-IR. The SVZ and GCL areas decreased approximately 50% 7 days after IR. The development of white matter was hampered, resulting in 50-70% less myelin basic protein staining. Pretreatment with erythropoietin did not confer protection against IR. Caspase inhibition by overexpression of XIAP prevented caspase-9 and caspase-3 activation but not cell death, presumably because of increased caspase-independent cell death.

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 complications of pediatric brain tumors: case series and literature review

The survival rate for childhood cancer, including brain tumors, is increasing. As a result, long-term sequelae of chemotherapy and radiotherapy are also increasing. The purpose of this study was to determine the frequency of endocrine complications of therapy for brain tumors in pediatric patients. Endocrinopathy was observed in 19 of 20 (95%) of patients with supratentorial midline tumors. Fifty-seven patients with nonmidline tumors (22 supratentorial, 35 posterior fossa) were followed for a mean of 4.6 +/- 2.4 years. Twenty-two endocrinopathies occurred in 16 patients treated as follows: one of 23 patients (0.4%) had surgery alone, zero of four (0%) had chemotherapy alone, eight of 18 (44%) had radiotherapy alone, and seven of 12 (58%) had both radiotherapy and chemotherapy. Endocrine disturbance was particularly common after craniospinal radiation (10 of 18 [55%]). Growth failure occurred in none of 23 patients who had surgery alone, in one of four patients who had chemotherapy (25%), in 11 of 18 patients who had radiotherapy (61%), in seven of 12 patients who received both radiotherapy and chemotherapy (58%), and in 12 of 18 patients who had craniospinal radiation (67%). In conclusion, endocrine and growth disturbances are uncommon with surgery alone, although they occurred in 53 and 60%, respectively, of patients treated with cranial irradiation for a brain tumor. This finding underscores the importance of routine endocrinology follow-up for all brain tumor patients receiving cranial irradiation. Literature review and endocrine surveillance recommendations are included.

The metabolic syndrome in long-term cancer survivors, an important target for secondary preventive measures

With increasing numbers of cancer survivors, attention has been drawn to long-term complications of curative cancer treatment, including a range of metabolic disorders. These metabolic disorders often resemble the components of the so-called metabolic syndrome, or syndrome X, which is an important risk factor for the development of cardiovascular disease. The mechanisms behind the development of metabolic disorders in cancer survivors have not been fully elucidated. However, association studies in the general population have demonstrated correlations between the components of the metabolic syndrome on the one hand and hormonal deficiencies, hypomagnesaemia, and endothelial dysfunction on the other. These latter disorders are regularly reported following curative cancer treatment and could, therefore, be important aetiologic factors in the development of the metabolic syndrome in cancer survivors. This review discusses data on the associations between the metabolic syndrome and treatment-related complications in cancer survivors and possibilities for preventive measures.

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.

Dosimetry and growth hormone deficiency following cranial irradiation of childhood brain tumors

BACKGROUND

Dosimetry of the hypothalamus-pituitary (HP) region could allow prediction of the risk of growth hormone deficiency (GHD) following cranial irradiation.

PROCEDURE

Nineteen children (15 boys) with a median age of 6.3 years (range 1.7-16.5) at the time of irradiation of a brain tumor not involving the HP axis were followed for 1.2-6.3 years (median 3.4) from radiotherapy (RT). The dose to a standardized anatomical model including the HP region was calculated from dose-volume histograms of 10% to 100% in steps of 10% of the HP model based on data from a computer-based treatment planning system. If GHD was suspected from insulin-like growth factor-I, serum insulin-like growth factor binding protein-3, and/or height velocity measurements, an arginine stimulation test was performed. GHD was defined by a peak GH <15mU/liter.

RESULTS

Ten patients developed GHD 10-26 months from irradiation. Cox regression analysis identified the 90% dose-volume of the HP box as the strongest predictor of development of GHD (P = 0.03). The median dose to the 90% dose-volume of the HP region was 37.5 Gy (range 2. 3-55.3). The cumulated risk of GHD 2.5 years after radiotherapy for children receiving more than and less than 37.5 Gy to the HP region was 87% and 33%, respectively (P = 0.036).

CONCLUSIONS

Dosimetry of a defined HP volume provides the opportunity to 1) calculate the exact dose delivered to this region, 2) predict the risk of GHD and, 3) in the future revise the treatment planning and thus reduce the risk of endocrine adverse effects.

Optimization of stereotactically-guided conformal treatment planning of sellar and parasellar tumors, based on normal brain dose volume histograms

PURPOSE

To investigate the optimal treatment plan for stereotactically-guided conformal radiotherapy (SCRT) of sellar and parasellar lesions, with respect to sparing normal brain tissue, in the context of routine treatment delivery, based on dose volume histogram analysis.

METHODS AND MATERIALS

Computed tomography (CT) data sets for 8 patients with sellar- and parasellar-based tumors (6 pituitary adenomas and 2 meningiomas) have been used in this study. Treatment plans were prepared for 3-coplanar and 3-, 4-, 6-, and 30-noncoplanar-field arrangements to obtain 95% isodose coverage of the planning target volume (PTV) for each plan. Conformal shaping was achieved by customized blocks generated with the beams eye view (BEV) facility. Dose volume histograms (DVH) were calculated for the normal brain (excluding the PTV), and comparisons made for normal tissue sparing for all treatment plans at > or =80%, > or =60%, and > or =40% of the prescribed dose.

RESULTS

The mean volume of normal brain receiving > or =80% and > or =60% of the prescribed dose decreased by 22.3% (range 14.8-35.1%, standard deviation sigma = 7.5%) and 47.6% (range 25.8-69.1%, sigma = 13.2%), respectively, with a 4-field noncoplanar technique when compared with a conventional 3-field coplanar technique. Adding 2 further fields, from 4-noncoplanar to 6-noncoplanar fields reduced the mean normal brain volume receiving > or =80% of the prescribed dose by a further 4.1% (range -6.5-11.8%, sigma = 6.4%), and the volume receiving > or =60% by 3.3% (range -5.5-12.2%, sigma = 5.4%), neither of which were statistically significant. Each case must be considered individually however, as a wide range is seen in the volume spared when increasing the number of fields from 4 to 6. Comparing the 4- and 6-field noncoplanar techniques to a 30-field conformal field approach (simulating a dynamic arc plan) revealed near-equivalent normal tissue sparing.

CONCLUSION

Four to six widely spaced, fixed-conformal fields provide the optimum class solution for the treatment of sellar and parasellar lesions, both in terms of normal brain tissue sparing and providing a relatively straightforward patient setup. Increasing the number of fields did not result in further significant sparing, with no clear benefit from techniques approaching dynamic conformal radiotherapy in the cases examined.

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.

Metastasis stage, adjuvant treatment, and residual tumor are prognostic factors for medulloblastoma in children: conclusions from the Children's Cancer Group 921 randomized phase III study

PURPOSE

From 1986 to 1992, "eight-drugs-in-one-day" (8-in-1) chemotherapy both before and after radiation therapy (XRT) (54 Gy tumor/36 Gy neuraxis) was compared with vincristine, lomustine (CCNU), and prednisone (VCP) after XRT in children with untreated, high-stage medulloblastoma (MB).

PATIENTS AND METHODS

Two hundred three eligible patients with an institutional diagnosis of MB were stratified by local invasion and metastatic stage (Chang T/M) and randomized to therapy. Median time at risk from study entry was 7.0 years.

RESULTS

Survival and progression-free survival (PFS) +/- SE at 7 years were 55%+/-5% and 54%+/-5%, respectively. VCP was superior to 8-in-1 chemotherapy, with 5-year PFS rates of 63%+/-5% versus 45%+/-5%, respectively (P = .006). Upon central neuropathology review, 188 patients were confirmed as having MB and were the subjects for analyses of prognostic factors. Children aged 1.5 to younger than 3 years had inferior 5-year estimates of PFS, compared with children 3 years old or older (P = .0014; 32%+/-10% v 58%+/-4%, respectively). For MB patients 3 years of age or older, the prognostic effect of tumor spread (MO v M1 v M2+) on PFS was powerful (P = .0006); 5-year PFS rates were 70%+/-5%, 57%+/-10%, and 40%+/-8%, respectively. PFS distributions at 5 years for patients with M0 tumors with less than 1.5 cm2 of residual tumor, versus > or = 1.5 cm2 of residual tumor by scan, were significantly different (P = .023; 78%+/-6% v 54%+/-11%, respectively).

CONCLUSION

VCP plus XRT is a superior adjuvant combination compared with 8-in-1 chemotherapy plus XRT. For patients with M0 tumors, residual tumor bulk (not extent of resection) is a predictor for PFS. Patients with M0 tumors, > or = 3 years with < or = 1.5 cm2 residual tumor, had a 78%+/-6% 5-year PFS rate. Children younger than 3 years old who received a reduced XRT dosage had the lowest survival rate.

The long-term effect on PSA values of incidental prostatic irradiation in patients with pelvic malignancies other than prostate cancer

PURPOSE

To determine the effect of external beam radiation therapy on serum prostate-specific antigen (PSA) production by the benign prostate.

METHODS AND MATERIALS

We studied a cohort of 24 men receiving treatment for cancer of the bladder or rectum. The radiation fields in all cases encompassed the prostate gland, and none of the patients were known to have prostate cancer. All patients had 2 or more PSA estimations obtained in the years following their radiation treatment. A second group of 46 patients who had undergone radical external beam radiation therapy for prostate cancer and who were clinically disease free 8-22 years later were also observed, with a median of 5.8 years of PSA observations.

RESULTS

Only 3 of the 24 patients in the first group showed a significant rise of > 0.2 ng/ml in their serum PSA levels, with a median of 3.3 years follow-up from the first PSA test. Seven of 24 showed progressive declines, and 14 of 24 showed steady levels. The median PSA for this group was < or = 0.5 ng/ml. Only 6 of the 46 in the second group showed a PSA rise of > 0.2 ng/ml. Thirty-four had stable values, and 6 had further declines. Again, the median PSA for the entire group was < or = 0.5 ng/ml.

CONCLUSION

Recovery of prostatic secretory function is an uncommon event after external beam radiation. The concern that this might significantly confound new definitions of biochemical failure after radical radiation for prostate cancer that are based on progressively rising PSA values thus appears to be unfounded.

Growth failure after treatment of pediatric brain tumors

OBJECTIVES

Primary brain tumors are the most common solid tumors that occur in childhood. With improved management of these tumors, there are more survivors with long-term sequelae of radiation and chemotherapy including growth failure. The aim of this study was to assess growth prospectively in children with nonpituitary-related primary brain tumors.

METHODS

Forty-one children 3.1 to 13.8 years of age diagnosed consecutively between 1989 and 1992 with a primary nonpituitary-related brain tumor were studied.

RESULTS

Of 34 prepubertal children, 14 (41%) were diagnosed as having growth hormone (GH) deficiency. All 14 children were treated with cranial irradiation. During the first year from completion of brain tumor therapy, the annual height velocity of those children confirmed subsequently as being GH-deficient was 3.06 +/- 1.19 cm compared with 5.29 +/- 2.21 cm for those who were not GH-deficient. During the second year, the annual height velocity was 3.29 +/- 1.14 cm per year for the GH-deficient group compared with 5.48 +/- 1.24 cm per year for the non-GH-deficient group. All children with GH deficiency received cranial irradiation and chemotherapy. Two of 34 children developed precocious puberty. Primary hypothyroidism was diagnosed in 6 of 41 children (12%).

CONCLUSION

We conclude that GH deficiency and primary hypothyroidism are common after cranial irradiation and chemotherapy for nonpituitary-related brain tumors. Linear growth appears to reflect GH status accurately in children with brain tumors. Precise auxologic evaluation is simple and noninvasive and may reflect more accurately GH status than provocative GH testing. These findings reflect the need for prospective growth monitoring of children with nonpituitary-related brain tumors treated with cranial irradiation and chemotherapy. Early diagnosis of GH deficiency facilitates early initiation of GH therapy and optimization of final height.

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.

Medulloblastoma: time-dose relationship based on a 30-year review

PURPOSE

Time-dose relationships have proven important in many cancer sites. This study evaluates the time factors involved in the successful postoperative radiotherapy of medulloblastoma, based on a 30-year experience in a single institution.

METHODS AND MATERIALS

Fifty-three patients with medulloblastoma received postoperative craniospinal radiotherapy with curative intent between 1963 and 1993. Seven patients (13%) underwent biopsy alone, 28 patients (53%) had subtotal excision, and 18 patients (34%) had gross total excision. Eleven patients received adjuvant chemotherapy. The mean posterior fossa dose was 53.1 Gy; most patients received 54.0 Gy (range, 34.3 to 69.6 Gy). For 41 patients receiving once-a-day therapy, the mean dose was 50.6 Gy (range, 34.3 to 56.0 Gy). For 12 patients receiving twice-a-day therapy, the mean dose was 61.8 Gy (range, 52.6 to 69.6 Gy). Minimum follow-up was 2 years, and median follow-up was 10.7 years. Survival, freedom from relapse, and disease control in the posterior fossa were calculated using the Kaplan-Meier method, and multivariate analysis was performed for prognostic factors. Variables related to radiotherapy were examined, including dose to the craniospinal axis, dose to the posterior fossa, fractionation (once-a-day vs. twice-a-day), use of adjuvant chemotherapy, risk group [high (> or =T3b or > or =M1) or low (< or =T3a and M0-MX)], interval between surgery and radiotherapy (excluding patients receiving chemotherapy before radiotherapy), and duration of radiotherapy.

RESULTS

At 5 and 10 years, overall survival rates were 68 and 64%, respectively, and freedom-from-relapse rates were 61 and 52%, respectively. Rates of disease control in the posterior fossa at 5 and 10 years were 79 and 68%, respectively. At 5 years, absolute survival rates after biopsy alone, subtotal excision, and gross total excision were 43, 67, and 78%, respectively (p=0.04), and posterior fossa control rates were 27, 89, and 83%, respectively (p=0.004). Duration of the treatment course was the only radiotherapy-related variable with a significant impact on freedom from relapse and posterior fossa control. For patients whose radiation treatment duration was < or =45 days, posterior fossa control was 89% at 5 years, compared with 68% for those treated for >45 days (p=0.01). Duration of treatment also affected freedom from relapse at 5 years: < or =45 days (76%) compared with >45 days (43%), p=0.004.

CONCLUSION

Our study demonstrates that if adequate doses are used, then radiotherapy treatment duration will significantly affect the outcome in terms of control of disease in the posterior fossa and freedom from relapse. Fractions of at least 1.75 Gy given once a day, or a twice-a-day regimen should yield optimal local control results.

Radiation therapy and malignant degeneration of benign supratentorial gangliogliomas

OBJECTIVE

Gangliogliomas are indolent tumors comprised of neoplastic glial and neuronal cells. Benign lesions tend to be associated with long survival unless the tumor degenerates to a histologically malignant form. This study reviews four cases of histologically proven benign ganglioglioma that later demonstrated malignant features within the glial component of the tumor. Features common to each case are analyzed, and similar cases from the literature are reviewed.

METHODS

The records of 42 supratentorial gangliogliomas operated on at our institution since 1985 were reviewed. Special attention was paid to histological characteristics, use of adjuvant radiotherapy, time to tumor recurrence, and histology of the recurrent tumor.

RESULTS

Of the 42 cases of gangliogliomas, 29 were initially histologically benign. Of these 29, 14 received postoperative radiation therapy and 14 did not; it was unclear whether one patient received adjuvant radiotherapy, and this patient was excluded from further analysis. Four benign gangliogliomas exhibited malignant degeneration of the glial component. These four all occurred in patients who had undergone postoperative irradiation. The time to identified histological change within recurrent tumors averaged 65 months (range, 22-144 mo).

CONCLUSION

All of the benign gangliogliomas undergoing malignant change had postoperative radiation therapy as a common feature. This represents a potential correlation that requires further study.

Induction chemotherapy followed by reduced-volume radiation therapy for newly diagnosed central nervous system germinoma

OBJECT

Although curative, radiation, which is conventionally administered for germinomas, causes significant neurological sequelae. This study aimed at reducing the volume and dose of radiation to a localized level of 24 Gy by pretreating the patient with chemotherapy.

METHODS

Seventeen patients were divided into two risk groups based on serological findings and the extent of tumor. They were treated with chemotherapy prior to receiving localized radiation therapy. Six patients with solitary pure germinomas were treated with three or four cycles of cisplatin and etoposide (EP regimen) followed by 24-Gy local radiation therapy. Eleven patients with human chorionic gonadotropin (HCG)-secreting, multifocal, or disseminated germinomas received four to five cycles of ifosfamide, cisplatin, and etoposide (ICE regimen) followed by 24-Gy local radiation therapy. Craniospinal ports were used only in three cases of germinomas with dissemination. Gross-total resection was performed in three patients. Fourteen patients were able to be evaluated for their responses to chemotherapy. All patients achieved a complete response within three cycles. At a median follow-up duration of 24 months, 16 patients (94%) were alive without recurrence. One patient with an HCG-secreting germinoma experienced recurrence 38 months after surgery. That patient underwent successful salvage therapy using the same protocol. Thus, all 17 patients became free of disease with a 70 to 100% Karnofsky Performance Scale status. Toxicities associated with this study's chemotherapy regimen were mostly transient. No patient showed neurological or endocrinological deterioration during the follow-up period.

CONCLUSIONS

The EP and ICE regimens were highly effective in treating the central nervous system germinomas and permitted dose and volume reduction of the radiotherapy. Localized 24-Gy irradiation was sufficient for disease control.