Greater susceptibility to hypothalamopituitary irradiation in younger children with acute lymphoblastic leukemia

Central Endocrine Complications Among Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

Children who receive cranial radiation therapy (RT) as a component of treatment for malignancy are often at risk of long-term central endocrine toxicity secondary to radiation to the hypothalamic-pituitary axis (HPA). A comprehensive analysis was performed of central endocrine late effects in survivors of childhood cancer treated with RT as part of the Pediatric Normal Tissue Effects in the Clinic (PENTEC) consortium.

METHODS AND MATERIALS

A systematic review of the risk of RT-related central endocrine effects was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A total of 4629 publications were identified, of which 16 met criteria for inclusion in dose modeling analysis, with a total of 570 patients in 19 cohorts. Eighteen cohorts reported outcomes for growth hormone deficiency (GHD), 7 reported outcomes for central hypothyroidism (HT), and 6 reported outcomes for adrenocorticotropic hormone (ACTH) deficiency.

RESULTS

Normal tissue complication probability modeling for GHD (18 cohorts, 545 patients) yielded D50 = 24.9 Gy (95% CI, 20.9-28.0) and γ50 = 0.5 (95% CI, 0.27-0.78). The normal tissue complication probability model fit for whole brain irradiation in children with a median age of >5 years indicated a 20% risk of GHD for patients who receive a mean dose of 21 Gy in 2-Gy fractions to the HPA. For HT, among 7 cohorts (250 patients), D50 = 39 Gy (95% CI, 34.1-53.2) and γ50 = 0.81 (95% CI, 0.46-1.35), with a 20% risk of HT in children who receive a mean dose of 22 Gy in 2-Gy fractions to the HPA. For ACTH deficiency (6 cohorts, 230 patients), D50 = 61 Gy (95% CI, 44.7-119.4) and γ50 = 0.76 (95% CI, 0.5-1.19); there is a 20% risk of ACTH deficiency in children who receive a mean dose of 34 Gy in 2-Gy fractions to the HPA.

CONCLUSIONS

RT dose to the HPA increases the risk of central endocrine toxicity, including GHD, HT, and ACTH deficiency. In some clinical situations, these toxicities may be difficult to avoid, and counseling of patients and families with respect to anticipated outcomes is important.

Fertility Preservation for Prepubertal Patients at Risk of Infertility: Present Status and Future Perspectives

The increasing cure rate of cancer has led to a vast population of survivors having to face the late adverse effects of oncological treatments, with fertility impairment being one of the most sensitive issues for patients. Different options to preserve the fertility of adult patients are routinely used in clinical practice. However, fertility preservation strategies for prepubertal patients at risk of infertility are limited to the cryopreservation of immature gonadal tissue. In recent decades, many research efforts have been focused on the future use of cryopreserved gonadal tissue. This review discusses the common status of fertility preservation measures for pediatric patients undergoing gonadotoxic treatment, focusing especially on the challenges that remain to be solved in order to implement this fundamental service.

Dual Characters of GH-IGF1 Signaling Pathways in Radiotherapy and Post-radiotherapy Repair of Cancers

Radiotherapy remains one of the most important cancer treatment modalities. In the course of radiotherapy for tumor treatment, the incidental irradiation of adjacent tissues could not be completely avoided. DNA damage is one of the main factors of cell death caused by ionizing radiation, including single-strand (SSBs) and double-strand breaks (DSBs). The growth hormone-Insulin-like growth factor 1 (GH-IGF1) axis plays numerous roles in various systems by promoting cell proliferation and inhibiting apoptosis, supporting its effects in inducing the development of multiple cancers. Meanwhile, the GH-IGF1 signaling involved in DNA damage response (DDR) and DNA damage repair determines the radio-resistance of cancer cells subjected to radiotherapy and repair of adjacent tissues damaged by radiotherapy. In the present review, we firstly summarized the studies on GH-IGF1 signaling in the development of cancers. Then we discussed the adverse effect of GH-IGF1 signaling in radiotherapy to cancer cells and the favorable impact of GH-IGF1 signaling on radiation damage repair to adjacent tissues after irradiation. This review further summarized recent advances on research into the molecular mechanism of GH-IGF1 signaling pathway in these effects, expecting to specify the dual characters of GH-IGF1 signaling pathways in radiotherapy and post-radiotherapy repair of cancers, subsequently providing theoretical basis of their roles in increasing radiation sensitivity during cancer radiotherapy and repairing damage after radiotherapy.

Nutritional Status and Growth Deficit in Children and Adolescents with Cancer at Different Moments of Treatment

BACKGROUND

Nutrition deficits are common in children and adolescents undergoing cancer treatment and can contribute to a worse prognosis. There are scarce studies regarding this context considering different moments of treatment. The aim of this study was to evaluate the association between moment of treatment and nutritional status in children and adolescents with cancer.

METHODS

A retrospective study was performed from January 2013 to December 2015, including data from all clinical records of patients under 18 years old with cancer. Clinical, nutritional support and anthropometric data were collected at four moments of treatment from cancer diagnosis: diagnosis (t₀), 3 mo, (t₁), 6 mo, (t₂) and 1 year (t₃). In addition, nutritional indicators were evaluated. Generalized Estimating Equation models were performed to analyze changes on anthropometric indices throughout four moments of treatment.

RESULTS

The sample comprised 73 patients and frequency of nutritional deficits ranged from 13.0% to 18.6%. All nutritional indicators decreased at t₁, showed a modest recovery at t₂ and a stronger recovery at t₃ (p < 0.001). Growth was also impacted during treatment, mainly on patients under 2 years in the first three months of treatment.

CONCLUSIONS

Moment of treatment was associated with growth deficit and decreased percentiles in development indicators.

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.

DIAGNOSIS OF ENDOCRINE DISEASE: Endocrine late-effects of childhood cancer and its treatments

Endocrine complications are frequently observed in childhood cancer survivors (CCS). One of two CCS will experience at least one endocrine complication during the course of his/her lifespan, most commonly as a late-effect of cancer treatments, especially radiotherapy and alkylating agent chemotherapy. Endocrine late-effects include impairments of the hypothalamus/pituitary, thyroid and gonads, as well as decreased bone mineral density and metabolic derangements leading to obesity and/or diabetes mellitus. A systematic approach where CCS are screened for endocrine late-effects based on their cancer history and treatment exposures may improve health outcomes by allowing the early diagnosis and treatment of these complications.

Strategies to Overcome Late Complications from Radiotherapy for Childhood Head and Neck Cancers

Most pediatric head and neck cancers are treated with radiotherapy, but the morbidity associated with radiotherapy has become a prominent issue. This article discusses the common long-term complications associated with head and neck radiotherapy for childhood cancers. It reviews approaches to minimize toxicity and details the toxicities that head and neck radiation inflicts on relevant functional measures. In addition, it discusses the risk of radiation-induced secondary cancers in childhood cancer survivors, as well as strategies to reduce them. Thus, this article addresses approaches to minimize long-term radiation toxicities in order to improve the quality of life for childhood cancer survivors.

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.

Anterior hypopituitarism in adult survivors of childhood cancers treated with cranial radiotherapy: a report from the St Jude Lifetime Cohort study

PURPOSE

To estimate the prevalence of and risk factors for growth hormone deficiency (GHD), luteinizing hormone/follicle-stimulating hormone deficiencies (LH/FSHD), thyroid-stimulatin hormone deficiency (TSHD), and adrenocorticotropic hormone deficiency (ACTHD) after cranial radiotherapy (CRT) in childhood cancer survivors (CCS) and assess the impact of untreated deficiencies.

PATIENTS AND METHODS

Retrospective study in an established cohort of CCS with 748 participants treated with CRT (394 men; mean age, 34.2 years [range, 19.4 to 59.6 years] observed for a mean of 27.3 years [range, 10.8 to 47.7 years]). Multivariable logistic regression was used to study associations between demographic and treatment-related risk factors and pituitary deficiencies, as well as associations between untreated deficiencies and cardiovascular health, bone mineral density (BMD), and physical fitness.

RESULTS

The estimated point prevalence was 46.5% for GHD, 10.8% for LH/FSHD, 7.5% for TSHD, and 4% for ACTHD, and the cumulative incidence increased with follow-up. GHD and LH/FSHD were not treated in 99.7% and 78.5% of affected individuals, respectively. Male sex and obesity were significantly associated with LH/FSHD; white race was significant associated with LH/FSHD and TSHD. Compared with CRT doses less than 22 Gy, doses of 22 to 29.9 Gy were significantly associated with GHD; doses ≥ 22 Gy were associated with LH/FSHD; and doses ≥ 30 Gy were associated with TSHD and ACTHD. Untreated GHD was significantly associated with decreased muscle mass and exercise tolerance; untreated LH/FSHD was associated with hypertension, dyslipidemia, low BMD, and slow walking; and both deficits, independently, were associated with with abdominal obesity, low energy expenditure, and muscle weakness.

CONCLUSION

Anterior pituitary deficits are common after CRT. Continued development over time is noted for GHD and LH/FSHD with possible associations between nontreatment of these conditions and poor health outcomes.

Endocrine Disorders in Childhood Cancer Survivors Treated with Haemopoietic Stem Cell Transplantation

The increasing number of haemopoietic stem cell transplantations (HSCT) taking place worldwide has offered a cure to many high risk childhood malignancies with an otherwise very poor prognosis. However, HSCT is associated with an increased risk of morbidity and premature death, and patients who have survived the acute complications continue to face lifelong health sequelae as a result of the treatment. Endocrine dysfunction is well described in childhood HSCT survivors treated for malignancies. The endocrine system is highly susceptible to damage from the conditioning therapy, such as, alkylating agents and total body irradiation, which is given prior stem cell infusion. Although not immediately life-threatening, the impact of these abnormalities on the long term health and quality of life in these patients may be considerable. The prevalence, risk factors, clinical approaches to investigations and treatments, as well as the implications of ongoing surveillance of endocrine disorders in childhood HSCT survivors, are discussed in this review.

Bone mineral density deficits and fractures in survivors of childhood cancer

Although substantial increases in survival rates among children diagnosed with cancer have been observed in recent decades, survivors are at risk of developing therapy-related chronic health conditions. Among children and adolescents treated for cancer, acquisition of peak bone mass may be compromised by cancer therapies, nutritional deficiencies, and reduced physical activity. Accordingly, failure to accrue optimal bone mass during childhood may place survivors at increased risk for deficits in bone density and fracture in later life. Current recommendations for the treatment of bone density decrements among cancer survivors include dietary counseling and supplementation to ensure adequate calcium and vitamin D intake. Few strategies exist to prevent or treat bone loss. Moving forward, studies characterizing the trajectory of changes in bone density over time will facilitate the development of interventions and novel therapies aimed at minimizing bone loss among survivors of childhood cancer.

Radiation-induced hypopituitarism

PURPOSE OF REVIEW

Progressive and irreversible neuro-endocrine dysfunction following radiation-induced damage to the hypothalamic-pituitary (h-p) axis is the most common complication in cancer survivors with a history of cranial radiotherapy involving the h-p axis and in patients with a history of conventional or stereotactic pituitary radiotherapy for pituitary tumours. This review examines the controversy about the site and pathophysiology of radiation damage while providing an epidemiological perspective on the frequency and pattern of radiation-induced hypopituitarism.

RECENT FINDINGS

Contrary to the previously held belief that h-p axis irradiation with doses less than 40 Gy result in a predominant hypothalamic damage with time-dependent secondary pituitary atrophy, recent evidence in survivors of nonpituitary brain tumours suggests that cranial radiation causes direct pituitary damage with compensatory increase in hypothalamic release activity. Sparing the hypothalamus from significant irradiation with sterteotactic radiotherapy for pituitary tumours does not appear to reduce the long-term risk of hypopituitarism.

SUMMARY

Radiation-induced h-p dysfunction may occur in up to 80% of patients followed long term and is often associated with an adverse impact on growth, body image, skeletal health, fertility, sexual function and physical and psychological health. A detailed understanding of pathophysiological and epidemiological aspects of radiation-induced h-p axis dysfunction is important to provide targeted and reliable long-term surveillance to those at risk so that timely diagnosis and hormone-replacement therapy can be provided.

Postradiation therapy hypopituitarism

The increasing use of radiation treatment for head and neck cancers and other tumors, including pituitary adenomas, from the mid-20th Century onwards led to the recognition that pituitary function may be affected - often leading to some degree of pituitary insufficiency. Our knowledge is mostly based on observational or retrospective rather than randomized prospective studies. The various axes may be impacted at the hypothalamic or pituitary levels, or both. Some axes - the somatotropic and gonadotropic - appear to be especially vulnerable to radiation damage and may be affected quite early, whereas posterior pituitary function is rarely affected. Increased use of stereotactic radiosurgery, which focuses the radiation dose on the abnormal tissue, may be expected to reduce the impact on normal pituitary function, but such studies that are available are, as yet, relatively short term. Prospective studies of the effect of stereotactic radiosurgery on pituitary function would be valuable.

Prevalence and risk factors of radiation-induced growth hormone deficiency in childhood cancer survivors: a systematic review

BACKGROUND

Growth hormone deficiency (GHD) is usually the first and most frequent endocrine problem occurring after cranial radiotherapy (CRT). The aim of this systematic review was to evaluate the existing evidence of the prevalence and risk factors of radiation-induced GHD in childhood cancer survivors.

METHODS

MEDLINE, EMBASE and CENTRAL were searched for studies reporting on radiation-induced GHD in childhood cancer survivors. Information about study characteristics, prevalence and risk factors was abstracted and the quality of each study was assessed. A meta-regression analysis was performed.

RESULTS

The prevalence of radiation-induced GHD was estimated in 33 studies. Most studies had methodological limitations. The prevalence varied considerably between 0% and 90.9%. Selecting only the studies with adequate peak GH cut-off limits (<5 microg/L) resulted in 3 studies. In these studies the prevalence ranged from 29.0% to 39.1%, with a pooled prevalence of 35.6%. Higher CRT dose and longer follow-up time have been suggested to be the main risk factors of GHD by studies included in this review. The meta-regression analysis showed that the wide variation in the prevalence of GHD could be explained by differences in maximal CRT dose.

CONCLUSIONS

GHD is a frequent consequence after CRT in childhood cancer survivors. The prevalence of radiation-induced GHD ranged from 29.0% to 39.1% when selecting only studies with adequate peak GH cut-off limits. Higher CRT dose and longer follow-up time are the main risk factors. More well-designed studies are needed to accurately estimate the prevalence of GHD and to define the exact CRT threshold dose.

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.

Longitudinal growth and risk factors for growth deficiency in children treated for acute lymphoblastic leukemia

BACKGROUND

Growth deficit has been reported as a frequent complication of the treatment of acute lymphoblastic leukemia (ALL).

PROCEDURE

Longitudinal analysis of the growth of 129 children, from a total of 351 cases diagnosed between 1987 and 1994 in Brazil, was determined. Height data were converted into standard deviation Z scores. Only girls younger than 10 and boys younger than 12 years old at diagnosis were included. Patients were treated according to a German BFM-83 based protocol. Fifty-eight children received 18 Gy cranial irradiation, four 12 Gy, and two 24 Gy. Patients were aggregated into five non-excluding groups according to availability of height data at diagnosis, during the treatment, at the end of it, and several years after; 35 children reached their final height.

RESULTS

Height deficit at the end of the therapeutic treatment was evident (P < 0.0001). Catch-up occurred 1 year after stopping treatment (P = 0.016). At the last follow-up, over 5 years after the end of treatment (n = 83) or at final height (n = 35), impressive height deficits were recorded (P < 0.0001 for both end points). Multivariate analysis demonstrated that growth impairment was more severe in children younger than 4 years at diagnosis and in those who received cranial irradiation. No significant effect of gender was observed. Children who were treated solely with chemotherapy also had significant height loss.

CONCLUSIONS

Treatment of ALL in children is associated with growth deficit during the treatment and several years after it, affecting the final height negatively, particularly in patients younger than 4 and in those who received cranial irradiation.

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.

Seqüelas endócrinas da radioterapia no tratamento do câncer na infância e adolescência

A radioterapia resulta em endocrinopatias, osteoporose, obesidade e seqüelas neurológicas em pacientes tratados por câncer. A deficiência de GH é a complicação mais freqüente no eixo hipotálamo-hipofisário. A freqüência, prazo de surgimento e gravidade da deficiência de GH dependem da dose recebida durante a irradiação craniana, mas idade à radioterapia e fracionamento da dose também são variáveis importantes. Outras anormalidades do eixo hipotálamo-hipofisário são igualmente dose-dependentes. Baixas doses de irradiação induzem puberdade precoce ou avançada, enquanto altas doses provocam deficiência gonadotrópica. Complicações endócrinas secundárias à irradiação periférica, como distúrbios gonadais ou tireoidianos são descritos. Mesmo com secreção normal de GH, o crescimento pode ser comprometido por lesões ósseas após irradiação corporal total ou crânio-espinhal. Resultados melhores sobre a estatura final têm sido obtidos com reposição de GH em associação com o tratamento da puberdade precoce ou avançada. O objetivo desta revisão é a abordagem das seqüelas endócrinas tardias da radioterapia.

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.

Fertility in women treated with cranial radiotherapy for childhood acute lymphoblastic leukemia

BACKGROUND

Fertility impairments among women treated during childhood for cancer are known to occur after some, but not all, types of anticancer therapy. Although leukemia is the most common cancer of childhood, until now fertility in survivors has not been comprehensively assessed.

PROCEDURE

We investigated functional impairment of fertility in women who were long-term survivors of acute lymphoblastic leukemia (ALL) with a retrospective cohort study. Proven fertility (defined as ever pregnant) was evaluated by self-report among 182 females treated on protocols of the Children's Cancer Group (age at interview, 22.6 years on average) and 170 controls drawn from among the survivors' female siblings (23.4 years). The interview included psychosocial inventories designed to detect mood problems.

RESULTS

Significant fertility deficits were noted in female survivors treated with cranial radiotherapy (CRT) at any dose around the time of menarche (relative fertility (RF)) = 0.27, 95% CI = 0.09, 0.82, P = 0.03). Controlling for marital status, mood at interview, and many fertility-related situations did not change the association.

CONCLUSION

This study provides evidence for fertility deficits after treatment for ALL with CRT, and, in addition, for the first time, suggests that girls treated around the time of menarche are especially at risk. Clinical confirmation of these results is needed. If gonadal damage occurs in women receiving these treatments, their risk for further sequelae, such as osteoporosis and heart disease, may be significantly raised, requiring active management and intervention.

Fertility of long-term male survivors of acute lymphoblastic leukemia diagnosed during childhood

Fertility impairments among men treated during childhood for cancer are known to occur after some, but not all, types of anti-cancer therapy. This is the first study to evaluate proven fertility among adult male survivors of childhood acute lymphoblastic leukemia (ALL). In a retrospective cohort study, proven fertility (ever fathered a pregnancy) was evaluated by self-report among 213 men treated for ALL before age 18 on protocols of the Children's Cancer Group (CCG). Controls (N = 145) were drawn from among male siblings. Overall, with a proportional hazards analysis, proven fertility of male survivors was not different from that of controls (relative fertility (RF) = 0.95, 95% CI 0.63-1.43). However, married men treated before age 10 with high dose (24 cGy) cranial radiotherapy (RT), without spinal RT, had only 9% of the fertility of controls (Relative risk, RR = 0.09, 95% CI 0.01-0.82). High dose cranial RT at older ages was not associated with a statistically significant fertility deficit (RR = 0.56, 95% CI 0.25-1.28). In this first study of proven fertility among men treated for childhood leukemia, the majority of survivors showed no evidence of fertility impairment compared to controls. However, men treated at a young age with high dose cranial RT may have impaired fertility. These results suggest that further investigation of men with these treatments is needed to confirm and extend these findings.

Adult height and age at menarche in childhood cancer survivors

The aim of this study was to assess the long-term effects of cancer treatments on adult height and age at menarche in survivors of various types of childhood cancer. 285 childhood cancer survivors (161 men and 124 women), at least 18 years old and having been off treatment for at least 5 years, were examined. The effects of cranial (CrRT) and craniospinal irradiation (CrSpRT), other treatments and age at diagnosis on adult height and age at menarche were investigated. Patients who did not receive CrRT or CrSpRT, reached normal adult heights. However, a significant reduction in adult height was observed in men and women treated with CrRT or CrSpRT, especially if the treatment was given at the age of 8 years or younger. In girls, CrRT resulted in a significantly earlier menarche, compared with the Dutch population. Chemotherapy, radiation dose and age at menarche did not affect adult height. The relative risk (RR) of attaining an adult height below the 3rd percentile (20% 49/244) of the study population) was 6 times increased (RR=6.4; 95% confidence interval (CI) 1.46-28.52) after CrSpRT, 4 times (RR=4.2; 95% CI 1.81-9.63) after Crth and 5 times (RR=51; 95% CI 2.23-11.59) when irradiation was administered at the age of 8 years or younger. CrRT and CrSpRT and age at treatment are the main determinants of short stature in male and female childhood cancer survivors.

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.

Effects of puberty on bone age maturation in a girl after medulloblastoma therapy

BACKGROUND

Craniospinal radiotherapy for malignant brain tumors can result in a variety of neuroendocrine disturbances, among which are the development of growth hormone deficiency and early puberty, which can markedly reduce adult height.

METHODS

The authors report the case of a girl who received craniospinal radiotherapy for a medulloblastoma at the age of 3.4 years. At 9.1 years, growth hormone therapy was started, and spontaneous onset of puberty (Tanner stage B2) occurred at age 10.3 years. Interval until menarche was short, at only 0.9 years.

RESULTS

Although chronologic age at appearance of Tanner stages was within the normal range, the patient showed a rapid acceleration in skeletal maturation, resulting in adult short stature.

CONCLUSION

Bone age seems to be a more precise parameter for biologic maturation in some patients after craniospinal irradiation than is clinical assessment of pubertal stages. Thus, if progression of bone age and decreasing final height predictions are noted, puberty should be stopped with gonadotropin-releasing hormone analogs, even if pubertal development seems to be adequate for chronologic age, because this increases the remaining time for growth hormone treatment.

Thyroid function in children treated for acute lymphoblastic leukemia

To determine the late effects of treatment on thyroid function in children who survive acute lymphoblastic leukemia, we assessed plasma levels of thyroid hormones in 24 children (15 girls and 9 boys) who had received combination of chemotherapy along with 18-24 Gy of irradiation to the cranium. The children were aged between 1 and 10.5 years (mean 3.1) at diagnosis and thyroid status was investigated between 1.3 and 13 years (mean 6.8) after completion of therapy. Six children showed a low peak of plasma thyroid stimulating hormone (TSH), after stimulation with thyrotrophin-releasing hormone (TRH). Three children showed a low basal plasma TSH concentration. Serum levels of thyroxine (T4, fT4) and triiodothyronine (T3, fT3) were normal in all patients. The frequency of thyroid hypofunction (low peak response of TSH to TRH) was more common in children receiving 24 compared to 18 Gy cranial irradiation (50% vs 14%; odds ratio = 7) and those who had completed therapy more than 5 years ago (31.3% vs 12.5%, odds ratio 3.18) although no significant association could be found (95% IC: 0.27-65.8 and 0.24-90 respectively). Because of the low mean age at diagnosis of our population no significant association could be found between children younger than 3 years of age at diagnosis and thyroid hypofunction (odds ratio = 0.14; 95% IC: 0.01-1.48). We conclude that treatment for acute lymphoblastic leukemia including cranial irradiation may lead to TRH/TSH dysfunction and therefore long term survivors should be followed for a long period after completion of therapy.

Ultrasonography for thyroid screening after head and neck irradiation in childhood cancer survivors

We prospectively used ultrasonography to detect thyroid abnormalities in 96 long-term survivors of childhood cancer, who received head and neck radiation therapy at a median age of 8.9 years. The median time interval since irradiation was 10.8 years (range 5.6-22.8 years). Most survivors of leukemia received 24 Gy cranial irradiation for central nervous system prophylaxis; patients with solid tumors received between 20 and 66 Gy (median 37.5 Gy). The total evaluation included clinical history, physical examination, thyroid function tests, and thyroid ultrasonography; radionuclide scans were performed in patients whose abnormalities persisted on subsequent ultrasound exams. Clinical history and physical examination revealed thyroid abnormalities in 14 patients (15%), but ultrasound detected abnormalities in 42 patients (44%). These findings included inhomogeneity (n = 29), cysts (n = 15), and nodules (n = 22) and occurred in nearly half of patients treated with 15 Gy or more directly to the thyroid gland. Radionuclide scans confirmed the presence of thyroid nodules in 13 of 15 patients with ultrasonographic evidence of nodules. Six patients had thyroid neoplasia, including one case of papillary carcinoma. All patients with neoplasia had nodules demonstrated on ultrasonography. Our experience suggests that in childhood cancer survivors, ultrasonography is a sensitive, affordable, and noninvasive means of detecting subtle parenchymal abnormalities. We recommend thyroid ultrasonography for childhood cancer survivors who received head and neck irradiation. A baseline study should be obtained within 1 year of completion of therapy. The frequency of subsequent examinations should be based on the radiation dose and the patient's age at the time of irradiation.

Adult height after cranial irradiation with 24 Gy: factors and markers of height loss

The decrease in adult height of children who have been given cranial irradiation (24 Gy) for acute lymphoblastic leukaemia is attributed to chemotherapy, growth hormone (GH) deficiency and early puberty. This study evaluates the factors involved in the height loss between irradiation and adult height and its markers in 43 patients irradiated at 5.8 +/- 0.4 (SEM) years. The mean height loss was 0.9 +/- 0.2 SD in the children with a normal GH peak (n = 11), 1.7 +/- 0.2 SD in those with a low GH peak and untreated (n = 15) and 0.6 +/- 0.2 SD in those treated with GH (n = 17). The adult height was significantly lower than target height in all three groups. The height loss correlated negatively with the GH peak (p < 0.02) and with the age at onset of puberty (p < 0.05) in the first two groups with spontaneous growth, but not with the chemotherapy regimen or its duration, or the plasma insulin-like growth factor I (IGFI) and its GH-dependent binding protein (BP-3). Early puberty (onset at 8-10 years) occurred in 6 girls from the first two groups. At the first evaluation, 5.6 +/- 0.4 years after irradiation, the GH peak values after arginine-insulin stimulation correlated with the age at irradiation (p < 0.03), taking into account the time since irradiation. The plasma IGFI and BP-3 values were correlated with each other, but not with the GH peak. In conclusion, this study demonstrates the impact of GH deficiency and GH replacement therapy on adult height in children given cranial irradiation for leukaemia. They therefore should be evaluated for their GH secretion 1-2 years after the end of chemotherapy. GH therapy is indicated for those with low GH peak and decreased growth rate or no increase in growth rate despite puberty.

Clinical characteristics and factors affecting growth in long-term survivors of cancer

We evaluated clinical characteristics and growth in 51 (24 males) long-term survivors of childhood cancer (median follow up 12.7 years). Patients were shorter, had a higher proportion of body fat and higher systolic blood pressure than their controls. The change in relative height during treatment was -0.83 standard deviation score (S.D.S.) in patients with cranial irradiation and -0.32 S.D.S. in patients without cranial irradiation; the figures after treatment were -0.56 and 0.20 S.D.S., respectively. Half (r2 = 0.50) of the variation in growth retardation during therapy could be explained by the cumulative doses of 6-mercaptopurine (6-MP) and vincristine and relative height at diagnosis. Cranial irradiation, increased relative height at diagnosis and young age at diagnosis were significant predictors of growth failure over the total observation period, explaining 43% of the variation. We conclude that long-term survivors of childhood cancer have impaired linear growth, increased body fat mass and elevated systolic blood pressure. Young children who are tall for their age at diagnosis and treated with cranial irradiation have the highest risk of impaired growth after the diagnosis. High doses of 6-MP seem to contribute significantly to growth retardation during therapy.

Central nervous system toxicity of cancer therapy in children

Cancer treatment of the central nervous system has contributed positively to long-term disease-free survival from childhood cancers such as acute leukemia and medulloblastoma. However, intrathecal chemotherapy and whole brain radiation are associated with acute, subacute, and delayed toxicities. The purpose of this review article is to summarize what is known about critical events in prenatal and postnatal brain development; the pathophysiology of radiation and chemotherapy neurotoxicity and clinical manifestations and risk factors for acute, subacute, and delayed toxicities. The importance of long-term follow-up and for multidisciplinary interventions that focus on prevention as well as management of identified problems are addressed.

Growth, puberty and obesity after treatment for leukaemia

Final height, body proportions, pubertal growth and body mass index were studied retrospectively in 142 survivors of acute lymphoblastic leukaemia (ALL). Treatment consisted of combination chemotherapy and cranial irradiation (18 or 24 Gy). Significant standing height loss and disproportion, with a relatively short back, was seen in both radiation dose groups. Girls were more severely affected than boys. Pubertal growth was adversely affected, with a reduction in peak height velocity in both sexes. Puberty occurred early in girls but at the normal time in boys. Nearly half the group were obese at final height, with no significant difference in incidence between the sexes. The relative roles of cranial irradiation and chemotherapy in the disturbance of growth, puberty and body composition observed in survivors of childhood ALL remain unclear. The aetiology is almost certainly multifactorial, with radiation-induced growth hormone insufficiency, early puberty, steroids and chemotherapy all having a role.

Longitudinal growth and final height in long-term survivors of childhood leukaemia

Survival of children with acute lymphoblastic leukaemia (ALL) has increased considerably in recent years and data on the spontaneous growth and final height of these children are conflicting. Therefore, we analysed the longitudinal growth and final height in 52 survivors (33 females, 19 males) of childhood ALL. These children were diagnosed and treated in a single institution, all remained in first remission and were submitted to cranial irradiation with either 2400 or 1800 cGy. None of the patients received testicular or spinal irradiation. Median age at diagnosis was 4.2 (range 1.3-9.6) years in the first group (2400 cGy) and 3.9 (0.8-10.5) years in the second (1800 cGy). Standing height was measured at diagnosis, at the end of treatment (median 3.1 years after diagnosis), 6, 12, 24 months after the end of treatment, and finally at the completion of growth. In girls a significant decrease of mean height standard deviation score (SDS) during treatment and a catch up in growth after the end of therapy was followed by a second period of reduced growth. Mean final height SDS was significantly lower than the value at diagnosis in both groups of girls, but only in males treated with 2400 cGy. Mean overall loss in height SDS from diagnosis to final height was higher in females (-1.24) than in males (-0.40) (P = 0.009). Females < or = 4 years of age at diagnosis showed a higher loss in final height than females > 4 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Final attained height in patients successfully treated for childhood acute lymphoblastic leukemia

We evaluated final adult height in 109 patients treated for childhood acute lymphoblastic leukemia on two multiarm Pediatric Oncology Group protocols between 1974 and 1981. Fifty-one patients received 2400 cGy cranial irradiation (XRT), and 58 patients received no XRT. All patients had no central nervous system involvement at diagnosis, achieved and maintained a complete response, entered puberty spontaneously, and had achieved final height. Height data were converted to standardized deviation scores. Mean age at diagnosis was 7.8 +/- 4.2 years. Distribution of heights at diagnosis was similar to that of the U.S. population. Relative to gender-specific heights for the population, female subjects in this study had lower attained heights than male subjects (p = 0.03). There was a monotonic trend of patients treated at an earlier age to have a reduction in final height (p = 0.057). Cranial irradiation was strongly associated with final height (mean standardized deviation score with XRT = -1.04 and without XRT = -0.14; p < 0.001). Final height was not associated with age at diagnosis, prognostic risk group, or Pediatric Oncology Group protocol. By multivariate analysis, only XRT and XRT x age were significantly associated with final height (p < 0.001 and p = 0.002, respectively). There was no significant gender effect. We conclude that XRT is significantly associated with reduced final adult height after treatment for childhood acute lymphoblastic leukemia. For survivors, therapy devoid of XRT does not appear to affect final height.

Growth and growth hormone in children during and after therapy for acute lymphoblastic leukaemia

Growth impairment and growth hormone (GH) deficiency have been reported in children treated for acute lymphoblastic leukaemia (ALL). We have studied growth and GH secretion in a group of 50 patients, affected by ALL, during a 2- to 5-year period after diagnosis, and in 12 "long-term-survivors". We observed a significant decrease in growth velocity during the 1st year (in particular during the first 6 months) of therapy and a catch-up growth after the end of therapy. "Long-term survivors" did not exhibit a significant reduction of height standard deviation score (SDS), as compared to height SDS at diagnosis. None of the patients showed GH deficiency. Our data indicate that chemotherapy significantly affects growth of patients treated for ALL, whereas radiotherapy-at the doses used in this study-does not induce GH deficiency, at least not within 9 years after diagnosis.

Irradiation-induced growth failure

GH deficiency, skeletal disproportion and early or precocious puberty may complicate irradiation to the head or axial skeleton in childhood. Certain cohorts of children are at particular risk, including those irradiated for brain tumours and various haematological malignancies. Both GH deficiency and impaired spinal growth may result in short stature, whereas the occurrence of early puberty in association with GH deficiency reduces the time available for GH therapy. The age of the child at irradiation is critical in that, in younger children, the central nervous system is more radiosensitive, the severity of the subsequent skeletal disproportion is greatest and the onset of puberty earliest. It is the very young craniospinally-irradiated child who is most at risk of extreme short stature.

A novel variant of growth hormone (GH) insufficiency following low dose cranial irradiation

OBJECTIVE

We aimed to investigate the effect of low dose (1800 cGy) prophylactic cranial irradiation on physiological growth hormone secretion.

DESIGN

We performed an analysis of 24-hour serum GH profiles using 20-minute sampling.

PATIENTS

Forty-four children were studied, of whom 21 were long-term survivors of acute lymphoblastic leukaemia and 23 were normal children. They were further subdivided into prepubertal, pubertal and post-pubertal groups.

MEASUREMENTS

GH profiles were analysed by autocorrelation, Fourier transformation and spectral analysis of stationarized data, and peak detection using the Pulsar peak detection program. RESULTS In the normal children, there was a significant increase in the median (range) area under the curve (AUC) of the GH profile between the prepubertal and pubertal groups (62 (11-124) and 137 (142-158) IU/I/h respectively, (P less than 0.01)). There was also a change in the spectral analysis through puberty. The dominant frequencies were spread widely in the prepubertal and post-pubertal groups but sharply focused in the pubertal group. In the cranially irradiated children there was no significant increase in AUC between the prepubertal (62(13-110) IU/I/h) and pubertal groups (92 (14-163) IU/I/h). The wide range of dominant frequencies persisted in the pubertal cranially irradiated group due to the presence of additional high frequency pulses. The impression of a disturbance of the periodicity of GH secretion in the cranially irradiated pubertal group was further supported by the finding that the autocorrelation function in this group alone was not significantly different from that which would arise from random data.

CONCLUSIONS

A novel form of GH insufficiency has been observed after low dose irradiation in childhood in which an abnormality of periodicity and a quantitative reduction in GH secretion appears restricted to puberty.

Impaired pubertal growth in acute lymphoblastic leukaemia

The growth of 182 patients who were long term survivors of childhood acute lymphoblastic leukaemia was retrospectively analysed. All remained in first remission and were treated with either 1800 or 2400 cGy of cranial irradiation. None had been treated with either testicular or spinal irradiation. Ninety three (51 boys, 42 girls) were treated with 2400 cGy and 89 (42 boys, 47 girls) were treated with 1800 cGy cranial irradiation. All patients were treated with standard chemotherapy including intrathecal methotrexate in similar dose regimens in either group. Mean age (SD) at diagnosis in the group treated with 2400 cGy was 4.8 (2.6) years and mean age in the group treated with 1800 cGy was 6.5 (3.3) years. Mean height SD score at diagnosis in the 2400 cGy group was +0.29 and final height achieved was -0.63. Mean height SD score at the start of treatment in the group treated with 1800 cGy was +0.40 and mean final height was -0.53. There was a similar reduction in height SD score in both groups during the pubertal growth spurt. The decrement in height SD score was greater when treatment was administered at less than 7 years of age in either dose regimen, both in prepubertal and pubertal growth. However, the decrease in height SD score was found to be greater in girls than boys. There was a trend in both sexes for the onset of puberty to be at a younger age with a lower treatment dose of radiotherapy. However, in girls treated with the lower dose regimen there was a significant reduction in the mean age of onset of puberty which was 9.9 years. Our data suggest that girls treated at less than 7 years of age have a severe impairment of pubertal growth, which is probably a combination of the dual endocrinopathy of premature puberty and growth hormone insufficiency.

Dose dependency of time of onset of radiation-induced growth hormone deficiency

Growth hormone (GH) secretion during insulin-induced hypoglycemia was assessed on 133 occasions in 82 survivors of childhood malignant disease. All had received cranial irradiation with a dose range to the hypothalamic-pituitary axis of 27 to 47.5 Gy (estimated by a schedule of 16 fractions over 3 weeks) and had been tested on one or more occasions between 0.2 and 18.9 years after treatment. Results of one third of the GH tests were defined as normal (GH peak response, greater than 15 mU/L) within the first 5 years, in comparison with 16% after 5 years. Stepwise multiple linear regression analysis showed that dose (p = 0.007) and time from irradiation (p = 0.03), but not age at therapy, had a significant influence on peak GH responses. The late incidence of GH deficiency was similar over the whole dose range (4 of 26 GH test results normal for less than 30 Gy and 4 of 25 normal for greater than or equal to 30 Gy after 5 years), but the speed of onset over the first years was dependent on dose. We conclude that the requirement for GH replacement therapy and the timing of its introduction will be influenced by the dose of irradiation received by the hypothalamic-pituitary axis.

Radiation and hypothalamic-pituitary function

In adults, hypopituitarism is a common consequence of external radiotherapy. The clinical manifestations may be subtle and develop insidiously many years after radiotherapy. Anterior pituitary deficiencies can therefore only be detected by regular testing, including dynamic tests of GH and ACTH reserve. Although the deficiencies most commonly develop in the order GH, gonadotrophins, ACTH then TSH, this sequence may not be predictable in an individual patient and comprehensive testing is therefore required. The tests should ideally be performed annually for at least 10 years after treatment or until deficiency has been detected and treated. It is not only the patients with pituitary disease who are at risk of developing hypopituitarism after radiotherapy. Any patient who receives a total dose of irradiation of 20 Gy or more to the hypothalamic-pituitary axis is at risk of hypopituitarism, although the threshold dose may be lower than this. This is particularly important in the long-term survivors of malignant disease in whom endocrine morbidity may be relatively common and in whom this can be easily treated, with consequent improvement in quality of life. Whilst patients who receive a high total dose of irradiation are at increased risk of developing multiple deficiencies, a higher fraction size also increases the risk of anterior pituitary failure. There is good evidence that the earliest damage to the hypothalamic-pituitary axis after external radiotherapy is at the level of the hypothalamus. However, patients who undergo pituitary ablation with interstitial radiotherapy or heavy particle beams are likely to sustain direct damage to the pituitary. In these patients, the sequence in which individual pituitary hormone deficiencies develop is generally the same as that observed with the hypothalamic damage after conventional external radiotherapy. The increasing use of radiotherapy as a means of treatment for malignant disease means that new groups of patients with potential for endocrine dysfunction are emerging. Whole body irradiation in the preparation for bone marrow transplant is one such treatment and although hypothalamic-pituitary damage appears to be confined to GH deficiency in children, longitudinal experience is limited to date, particularly in adults. The treatment of malignant disease in childhood is of particular importance in terms of the delayed endocrine sequelae. The hypothalamic-pituitary axis may not be the only endocrine tissue damaged by treatment in these patients and management is therefore more complicated. In the growing child, the potential association of growth hormone deficiency, gonadal failure or premature puberty and thyroid dysfunction mean that expert endocrine supervision is essential for optimum long-term outcome.

The effect of the number of fractions of cranial irradiation on growth in children with acute lymphoblastic leukaemia

Growth was documented over a period of 7 years in all long-term survivors treated for acute lymphoblastic leukaemia (ALL) with the DAL-70- (n = 15) and BFM-70-protocol (n = 27). Normal growth was documented in patients of the DAL-70-protocol during and after therapy. In contrast, in children treated with the BFM-70-protocol the mean height standard deviation score (SDS) decreased significantly from 1.21 SDS prior to therapy to 0.80 SDS at the end of therapy (p less than 0.001) and remained unchanged thereafter. Prophylactic cranial irradiation was given in total doses of 15 to 30 Gy. Ten children of the DAL-70- and 20 children of the BFM-70-protocol received 24 Gy of cranial irradiation. No significant change in height-SDS was observed in any patients of the DAL-70- and in 8 patients of the BFM-70- group, who received 24 Gy of cranial irradiation in 16-26 fractions. Adult height in 7 girls and 6 boys was normal and 3.15 cm and 5.06 cm above target height. In the remaining 12 patients of the BFM-70-protocol the total dose of 24 Gy of cranial irradiation was applied in 11-14 fractions. Their height-SDS had fallen significantly from 1.24 SDS before to 0.66 SDS (p less than 0.001) at the end of therapy. Adult height in 4 girls and 6 boys was also normal, but the height increase was comparatively smaller, -2.20 cm below target height in the girls and 1.91 cm above in the boys.(ABSTRACT TRUNCATED AT 250 WORDS)

Precocious and premature puberty associated with treatment of acute lymphoblastic leukaemia

Early puberty in 28 children (23 girls, five boys) treated for acute lymphoblastic leukaemia (ALL) at a mean age of 4.0 years (range 1.4-7.8) is described. All but one had received prophylactic cranial irradiation (1800-2400 cGy) and three children had received additional cranial or craniospinal irradiation as treatment for relapse of their leukaemia. Mean age for the onset of puberty was 8.8 (SD 0.8) years in the girls and 9.3 (0.8) years in the boys; this is greater than two standard deviations from the mean for normal girls and boys. Five children (three girls, two boys) had precocious puberty. The onset of puberty occurred at greater than two standard deviations from the mean for normal girls and boys in 14(13%) girls and 4(3%) boys treated at less than eight years of age between 1970 and 1985. In a group of 55 girls treated for ALL who had survived in first remission for six years or more from diagnosis, there was a relation between young age at onset of treatment and early menarche. We suggest that premature activation of the hypothalamic-pituitary-gonadal axis occurs as a consequence of hypothalamic dysfunction due to cranial irradiation. Precocious and premature puberty in children treated for ALL may be an important factor in contributing to short stature.