Growth and growth hormone in children after bone marrow transplantation

Hematopoietic reconstitution of neonatal immunocompetent mice to study conditions with a perinatal window of susceptibility

Efficient hematopoietic reconstitution of wild type mice requires preconditioning. Established experimental protocols exist to transplant hematopoietic stem cells into lethally irradiated or chemically myeloablated adult mice or unirradiated immunodeficient mice. We sought to develop a protocol to reconstitute immuno-replete neonatal mice. We describe irradiation and injection procedures for two-day old mice that lead to efficient long-term reconstitution of primary and secondary lymphoid organs. We demonstrate that the frequencies of lymphoid and myeloid cells in primary and secondary lymphoid organs are indistinguishable from unirradiated uninjected sex- and age-matched control animals by 5 weeks post-reconstitution. Thus, this system will facilitate studies aimed at understanding the developmental and environmental mechanisms that contribute to conditions that have a window of susceptibility during the perinatal period.

Virtual bolus for total body irradiation treated with helical tomotherapy

Intensity‐modulated radiation therapy (IMRT) for total body irradiation (TBI) is practiced in several centers using the TomoTherapy System. In this context the planning target volume (PTV) is the entire body including the skin. A safety margin in the air surrounding the body should be added to take into account setup errors. But using inverse planning, over‐fluence peak could be generated in the skin region to insure dose homogeneity. This work proposes to study the performance of the use of a virtual bolus (VB). A VB is a material placed on the skin surface during planning, but absent for the real treatment. The optimal VB that compensates large setup errors without introducing a high‐dose increase or hot spots for small setup errors was determined. For two cylindrical phantoms, 20 VBs with different densities, thicknesses or designs were tested. Dose coverage of the PTV (V95%) in the presence of simulated setup errors was computed to assess the VB performance. A measure of the dose increase in the phantom center due to the absence of the VB during treatment was also achieved. Finally, the fluence peak at the phantom edge was measured in complete buildup conditions using a large phantom and a detector matrix. Using these VBs, simulated setup errors were compensated to a minimum value of 2.6 and 2.1 cm for small and large phantom, respectively (and only 1.2 and 1.7 cm with no VB). An optimal double‐layer VB was found with a density of 0.4 kg.m−3 and a total thickness of 8 mm; an inner layer of 5 mm was declared as the target for the treatment planning system and an additional layer of 3 mm was added to avoid the over‐fluence peak. Using this VB, setup errors were compensated up to 2.9 cm. The dose increase was measured to be only +1.5% at the phantom center and over‐fluence peak was strongly decreased.

PACS numbers: 87.53 Bn, 87.55 D‐, 87.55 de, 87.55 dk

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.

Growth hormone (GH) secretion and response to GH therapy after total body irradiation and haematopoietic stem cell transplantation during childhood

OBJECTIVE

In January 1997 we introduced a protocol for the treatment with GH of children with impaired growth after unfractionated total body irradiation (TBI). This study is an evaluation of that protocol.

PATIENTS AND METHODS

Between January 1997 and July 2005, 66 patients (48 male) treated for haematological malignancies had at least two years of disease-free survival after TBI-based conditioning for stem cell transplantation (SCT). Stimulated and/or spontaneous GH secretion was decreased in 8 of the 29 patients tested because of impaired growth. Treatment with GH (daily dose 1.3 mg/m2 body surface area) was offered to all 29 patients and initiated in 23 of them (17 male). The main outcome measure was the effect of GH therapy on height standard deviation scores (SDS) after onset of GH therapy, estimated by random-effect modelling with corrections for sex, age at time of SCT and puberty (data analysed on intention-to-treat basis).

RESULTS

At time of analysis, median duration of therapy was 3.2 years; median follow-up after start of GH therapy was 4.2 years. The estimated effect of GH therapy, modelled as nonlinear (logit) curve, was +1.1 SD after 5 years. Response to GH therapy did not correlate to GH secretion status.

CONCLUSION

GH therapy has a positive effect on height SDS after TBI, irrespective of GH secretion status.

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.

Final adult height of patients who received hematopoietic cell transplantation in childhood

Growth impairment and growth hormone (GH) deficiency are complications after total body irradiation (TBI) and hematopoietic cell transplantation (HCT). To determine the impact of GH therapy on growth, the final heights of 90 GH-deficient children who underwent fractionated TBI and HCT for malignancy were evaluated. Changes in height standard deviation (SD) from the diagnosis of GH deficiency to the achievement of final height were compared among 42 who did and 48 who did not receive GH therapy. At HCT, GH-treated patients were younger (P = .001), more likely to have undergone central nervous system irradiation (P = .007), and shorter (P = .005) than patients who did not receive GH therapy. After HCT, GH deficiency was diagnosed at 1.5 years (range, 0.8-9.5 years) for GH-treated and 1.2 years (range, 0.9-8.8 years) for nontreated patients. GH therapy was associated with significantly improved final height in children younger than 10 years at HCT (P = .0001), but GH therapy did not impact the growth of older children. Girls (P = .0001) and children diagnosed with acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML), or myelodysplastic syndromes (MDS) (compared with acute lymphoblastic leukemia [ALL] or non-Hodgkin lymphoma [NHL]; P = .02) also showed more rapid growth than their counterparts. These data demonstrate that GH therapy improves the final height of young children after fractionated TBI.

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.

Effect on growth parameters of bone marrow transplantation with a chemotherapy-only conditioning regimen

INTRODUCTION

The increasing use of bone marrow transplantation (BMT) has increased survival among a growing number of children and young adults afflicted by malignant and nonmalignant hematologic disorders. Accordingly, quality of life has emerged as an important issue. Because they are a concern in this group, we assessed growth and development, following chemotherapy-only conditioning regimens.

MATERIALS AND METHODS

Twelve prepubertal children (8 boys, G(1)P(1) and 4 girls, B(1)P(1)) with a mean age of 6 +/- 2 years (age range: 3.5 to 10 years) before and at 3, 6, 9, and 12 months post-BMT.

RESULTS

Growth velocity at 1 year posttransplant was 10.0 +/- 3.5 cm/y. One year post-BMT, the statistical deviation saturation for growth velocity was 4.31 +/- 4.21. Height standard deviation score was -1.4 +/- 1.2 before and -0.5 +/- 1.3 1 year post-BMT (P <.004). The average weight of our subjects was 20 +/- 6 kg before and 26 +/- 9.5 kg 1 year post-BMT.

DISCUSSION

BMT with a chemotherapy-only conditioning regimen not only does not disturb growth in children; it is actually associated with a relative growth spurt afterward.

Endocrine complications of high-dose therapy with stem cell transplantation

Evaluations of endocrine function following hematopoietic cell transplantation demonstrate that the endocrine function abnormalities observed are related to the type of transplant preparative regimen received. Children given high dose cyclophosphamide (CY) only have normal thyroid function, normal growth and development. Children who received a busulfan (BU) plus CY preparative regimen usually have normal thyroid function, normal prepubertal growth, delayed or absent pubertal development, and blunted post-pubertal growth. Recipients of preparative regimens containing total body irradiation may be anticipated to have some thyroid dysfunction, impaired growth rates and delayed or absent pubertal development. Post-pubertal teens and young adults are likely to have gonadal function recover if they received a preparative regimen with CY only but are likely to have primary gonadal failure if they received a preparative regimen with BU or total body irradiation. Individuals whose gonadal function becomes normal have become parents of normal children. All patients who receive a marrow transplant should be followed long-term for development of endocrine function abnormalities.

Changes in height, weight and plasma leptin after bone marrow transplantation

Short stature can be a severe side-effect of bone marrow transplantation (BMT). Because of the effect of weight changes on growth rate and on plasma insulin-like growth factor (IGF I), we analyzed changes in height and body mass index (BMI) in 53 patients given BMT. Group 1 (n = 22) was given 12 Gy total body irradiation (TBI) as six fractions, group 2 (n = 14) 10 Gy TBI (one dose), group 3 (n = 8) 6 Gy total lymphoid irradiation (one dose), and group 4 (n = 9) chemotherapy alone. At the first evaluation, 13/36 patients in groups 1 and 2 had low growth hormone (GH) peaks after stimulation. The mean plasma IGF I concentrations (z score) were similar in groups 1 (-2.9 +/- 0.3) and 2 (-2.5 +/- 0.3), and in groups 3 (-1.4 +/- 0.3) and 4 (-1.4 +/- 0.7), but those of group 1 were lower than those of groups 3 (P < 0.01) and 4 (P < 0.05), and those of group 2 than those of group 3 (P < 0.05). BMI during the 5 years after BMT did not change in groups 1 and 2, decreased in group 3, and increased in group 4. However, these changes were not significant. Most of the patients given TBI had BMI below the mean at 2 (66%) and 5 (57%) years later. Their BMI and leptin concentrations correlated positively with each other (P = 0.005), and negatively with GH peak (P = 0.02 for BMI and 0.007 for leptin). In conclusion, this study suggests that TBI actually decreases GH secretion and is followed by a persistent low BMI. The negative relationship between GH peak and leptin may indicate that both are markers of a TBI-induced hypothalamic-pituitary lesion.

Prepubertal growth and growth hormone secretion in children after treatment for hematological malignancies, including autologous bone marrow transplantation

Prepubertal growth standards were used to assess growth in 20 children who had undergone autologous bone marrow transplantation (ABMT) as part of their treatment for hematological malignancy. Most of the patients (16 of 20) were transplanted after a relapse of their disease. A negative change in height standard deviation score (H-SDS) was seen only in the group of patients (n = 7) who had received both cranial irradiation therapy (CRT) and 7.5-Gy single-fraction total body irradiation (TBI). Height changes in this group were observed from the time of diagnosis. In contrast, the groups of patients conditioned with chemotherapy only (n = 3) or both chemotherapy and TBI, without preceding CRT (n = 10), did not demonstrate a significant loss in H-SDS. Weight related to height demonstrated large individual differences over time. Spontaneous growth hormone (GH) secretion, as measured by a four-point sleep curve, was followed longitudinally and an increasing proportion of patients with low peak levels was seen in all patient groups. In summary, prepubertal growth was suppressed only in patients who received cranial irradiation before ABMT. Despite low GH peak levels, normal prepubertal growth was found in patients with no CRT before ABMT.

[Total body irradiation: techniques, dosimetry, and complications]

Total-body irradiation (TBI) has an established role in many preparative regimens used before bone marrow transplantation (BMT) in the treatment of hematological malignancies in children and adults. Better choice in TBI techniques and dosimetry have permitted better homogeneity of dose, and therefore a significant sparing of critical tissues. Advances in treatments over the past 20 years have greatly improved survival; therefore, the evaluation of early and late complications, with a sufficient follow-up, according to different conditioning regimens is important. In this article, we review and compare different TBI techniques and dosimetry, and their influence on the distribution and homogeneity of dose, and the possible relationship to the risk of complications. We also describe the acute and late effects of TBI in children and adults appearing in the first month post-BMT as veno-occlusive disease, interstitial pneumonitis, or after 3 months, i.e., endocrinal late effects and growth in children, cataracts, neurological and bone or other complications, secondary tumors and alteration in the quality of life. The responsibility of TBI in the increased rate of certain complications is difficult to assess from chemotherapy or allograft side effects (chronic graft vs. host disease) or from other associated medical treatments, such as long term steroid therapy.

Growth and growth hormone secretion in children with cancer treated with chemotherapy

OBJECTIVE

To evaluate the effect of chemotherapy on growth and growth hormone (GH) secretion.

METHODS

We analyzed growth and GH secretion in 60 children in complete remission after treatment by chemotherapy and surgery for malignant solid tumors. None of them received cranial radiotherapy. Growth hormone reserve was assessed by at least two stimulation tests (clonidine, L-dopa, growth hormone-releasing hormone). In 12 children the reserve of GH pretreatment was also evaluated.

RESULTS

Growth hormone deficiency (GHD) was observed in 27 of 60 patients (45%). At diagnosis, mean standing height was +0.23 +/- 0.11 standard deviation score (SDS) in the GHD group and +0.16 +/- 0.10 SDS in the non-GHD group. After chemotherapy, mean standing height in the GHD group was -0.28 +/- 0.15 SDS and -0.14 +/- 0.11 in the non-GHD group (p < 0.05), and the growth rate was +0.13 +/- 0.07 SDS in the GHD group and +0.22 +/- 0.18 SDS in the non-GHD group. For a mean follow-up of 30 months, the mean standing height was -0.46 +/- 0.29 SDS in the GHD group and -0.24 +/- 0.16 SDS for the non-GHD group (p < 0.05), and the growth rate was -0.27 +/- 0.19 SDS in the GHD group and -0.16 +/- 0.12 SDS in the non-GHD group (p < 0.05). The GH response to clonidine was significantly less than that found with the other stimuli. There was correlation between the dose intensity of some drugs and the subsequent GH response to stimulation tests. The GHD group was found to have received significantly higher doses of actinomycin D than the non-GHD group (p < 0.05). Growth impairment and GHD were not found to be correlated with duration of treatment and follow-up, tumor type, sex, or age.

CONCLUSIONS

Chemotherapy as the sole form of treatment in children with cancer interferes with growth. The observed impairment of growth depends, at least in part, on a GHD related to chemotherapy. The growth rate in conjunction with the GH response to clonidine provides a sensitive measure of GHD associated with chemotherapy.

Contribution of growth hormone deficiency to the growth failure that follows bone marrow transplantation

Conditioning for bone marrow transplantation (BMT) by total body irradiation frequently causes growth failure. The contribution of growth hormone (GH) deficiency to this failure was assessed in 38 patients given three types of body irradiation: group 1 (n = 18) was given 12 Gy total body irradiation as six fractions, group 2 (n = 14) 10 Gy (one dose) total body irradiation, and group 3 (n = 6) 6 Gy (one dose) thoracoabdominal irradiation, which did not involve the hypothalamic-pituitary area. At the first evaluation, 2.9 +/- 0.2 (SE) years after BMT, the values for the plasma insulin-like growth factor I (IGF-I) and its GH-dependent binding protein (IGFBP-3) were similar in groups 1 and 2 but significantly greater in group 3 (p < 0.02 for IGF-I and 0.01 for IGFBP-3). These values were similar in those patients in groups 1 and 2 who had low GH peaks after stimulation (12 patients: IGF-I, 0.8 +/- 0.2 U/ml; IGFBP-3, 1.6 +/- 0.2 mg/L) and in those with normal GH peaks (20 patients: 1 +/- 0.1 U/ml and 1.8 +/- 0.1 mg/L). The decrease in height 2 years after BMT was significantly (p < 0.01) greater in group 2 than in groups 1 and 3, but 5 years after BMT it was similar in groups 1 and 2 (0.9 +/- 0.2 and 1.4 +/- 0.3 SD), significantly (p < 0.05) greater in group 2 than in group 3 (0.7 +/- 0.2 SD). The individual height changes between BMT and the last clinical evaluation before GH therapy were not correlated with the age at BMT, GH peak after stimulation, plasma IGF-I concentration, or IGFBP-3 concentration. Seven patients with GH deficiency were given GH therapy; their growth rate became normal for age (-2.1 +/- 0.9 SDS before and -0.2 +/- 0.4 SDS for the first year; not significant) without any catch-up growth. We conclude that plasma IGF-I and IGFBP-3 values are of no diagnostic value for GH deficiency after TBI. Their normal or high levels, despite low GH peaks, suggest that bone irradiation induces lesions causing resistance to IGF-I.

Growth in children undergoing bone marrow transplantation after busulfan and cyclophosphamide conditioning

PURPOSE

The purpose of this study was to evaluate the effect of busulfan and cyclophosphamide (BUCY) as conditioning regimen for bone marrow transplantation (BMT) on growth of children following BMT.

PATIENTS AND METHODS

Growth assessment was prospectively done in all 25 children who underwent BMT following BUCY conditioning from 1989 to 1994 at Children's Hospital of Philadelphia. The height and growth rates were expressed as standard deviation scores (SDS). The height SDS prior to BMT were compared with 1, 2, and 3 years post-BMT. The growth rate SDS 1 year and 2 years post-BMT were also compared. Pubertal children were excluded from the analysis of growth rate. Median age of patients was 7 years (range, 1.3-15 years). A total of 22/25 patients were transplanted for AML, and three patients had myelodysplastic syndrome. Equal numbers of patients had autologous and allogeneic transplants. Seven patients received corticosteroids for varying lengths of time. The pre-BMT height SDS (mean +/- SD) for the group was -0.4 +/- 1.3. The mean height SDS for 19 children at 1 year post-BMT was +/- 0.1 +/- 1.2 and for 10 children, 2 years post-BMT was -0.3 +/- 1.6. Seven children who were 3 years post-BMT had the mean height SDS of -0.2 +/- 1.5. There was no statistically significant difference between pre-BMT height SDS and 1 year post-BMT (p = 0.49) and 2 years post-BMT (p = 0.42). The mean growth rate at 1 year post-BMT was -0.1 +/- 2.7 and at 2 years post-BMT was -0.9 +/- 2.3. The difference was not statistically different (p = 0.15). Somatomedin-C (insulin growth factor 1, IGF-1) levels were normal in all 13 children tested at 1 year post-BMT. IGF binding protein (BP)-3 levels were done in 10 children at 1 year and were found to be normal in all. Thyroid function studies were done in all patients pre-BMT and 1 year post-BMT and were normal for all. Bone age assessment was appropriate for age in all 14 patients tested at 1 year post-BMT.

CONCLUSIONS

There was no evidence of growth failure following BMT with BUCY conditioning in this group of patients.

Final height and hormonal function after bone marrow transplantation in children

AIM

To analyze final height and hormonal function in long-term survivors of bone marrow transplantation (BMT).

PATIENTS

Group 1 consisted of 16 patients (10 boys) with a hematologic malignancy, mostly leukemia, conditioned for BMT with total body irradiation (TBI), 7.5 to 12 Gy, and cyclophosphamide. Group 2 consisted of 14 patients (9 boys) with severe aplastic anemia, conditioned with chemotherapy only.

RESULTS

In group 1, patients achieved a reduced final height after BMT. The difference between the height standard deviation score (SDS) at BMT and the height SDS at final height was -1.96 (0.82) SDS in boys and -0.92 (0.71) SDS in girls (p = 0.0001, and p = 0.02 respectively). Final height was also lower than target height (boys, p = 0.01; girls, p = 0.03). Prepubertal growth in the first 3 years after BMT was normal but pubertal height gain was decreased. The patients in group 2 achieved normal height. Thyroid function and adrenal function were normal in all patients, and no growth hormone deficiency was detected. Serum follicle-stimulating hormone values after BMT were increased in all group 1 patients, with return to normal in two patients. Serum luteinizing hormone values were increased in all group 1 girls, with recovery in one girl. Normal serum luteinizing hormone values and spontaneous puberty were found in all group 1 boys. In group 2, disturbances in gonadotropins were seen only in three boys and two girls.

CONCLUSION

In patients treated in childhood with BMT after chemotherapy and TBI with 7.5 Gy or more, final height is compromised because of blunted growth in puberty. Patients who had not received TBI suffered no height loss. In the majority of patients, the combination of chemotherapy and TBI also resulted in irreversible disturbances of gonadal function.

Growth in children after bone marrow transplantation for acute myelogenous leukemia as compared to acute lymphocytic leukemia

Previous studies of growth in children following bone marrow transplantation for leukemia have demonstrated poor growth with little ability to "catch-up" two to four years after transplantation. Because of small patient numbers, these studies did not distinguish patients with differing types of leukemia. 12 children with acute myelogenous leukemia who survived over 3 years after transplantation were compared with 12 who survived transplantation for acute lymphoblastic leukemia. The initial height standard deviation scores were similar in both groups prior to transplantation. The height standard deviation scores in the acute lymphoblastic leukemia group decreased for each of the 5 years after transplantation while the height score for the acute myelogenous leukemia group after 5 years was not statistically different from pre-transplantation. The growth of the children with myelogenous leukemia was better possibly because these children were older, had received less cranial irradiation at the time of transplantation, and had a lower incidence of severe chronic graft-versus-host disease.

Neuropsychological deficits in very young bone marrow transplant recipients

Bone marrow transplantation (BMT) involves conditioning with cyclophosphamide and, for patients with malignant disease, total body irradiation (TBI). This study describes the neuropsychological development of 10 children treated for leukemia (n = 7), neuroblastoma (n = 1) or severe aplastic anemia (SAA; n = 2) at 3 years of age or younger. A moderate general developmental delay, with pronounced motor deficits and varying degrees of perceptual and cognitive problems, was observed in all children treated for malignant disease. Children treated for SAA had normal development. We conclude that BMT, including TBI, can be directly associated with long-term neuropsychological impairment in children treated at a very young age. Continued medical and psychological follow-up procedures are needed.

Total body irradiation: a neuropsychological risk factor in pediatric bone marrow transplant recipients

Bone marrow transplantation (BMT) involves conditioning with cyclophosphamide and, for leukemic patients, total body irradiation (TBI). Based on the concern that this may lead to later neuropsychologic impairment in children, a longitudinal study was conducted. Thirty pediatric bone marrow transplant recipients, treated for leukemia or severe aplastic anemia (SAA), and their sibling donors, were given a neuropsychological examination in 1986 and 1988. A third follow-up study of patients treated before 12 years of age was undertaken in 1990-91. We present longitudinal data on patients treated with BMT when 3-11 (n = 15) and 12-17 (n = 11) years old. No neuropsychological deficits were found in the older group, or among non-irradiated SAA patients. In the first follow-up, children treated with BMT, including TBI at 3-11 years of age, performed less well than donors on tasks involving perceptual and fine-motor speed. In the second follow-up, this group of patients also demonstrated a slight deficit in non-verbal problem solving. An additional relative decline in verbal reasoning was noted in the third follow-up, 5.5-10 years after treatment. Alertness to signs of developmental difficulties in children treated with BMT, including TBI, is recommended.

Changes in craniofacial development induced by growth hormone therapy in children treated with bone marrow transplantation

The effect of growth hormone (GH) treatment on craniofacial development was studied in nine children exhibiting low growth velocity after bone marrow transplantation (BMT). Comparisons were made with seven BMT children who had not received GH. Two groups of age- and sex-matched healthy children served as controls for the respective patient groups. After an average observation period of 3.5 years, the BMT children not treated with GH exhibited significantly reduced mandibular length and alveolar height (p < 0.01). The increase in mandibular length was only 30% of that found in healthy controls. Maxillary growth was less affected by BMT treatment. In the GH treated group, no significant differences were found in craniofacial growth increments compared with controls. Although exogenous GH therapy in this group of children did not induce a catch-up growth, it appears to have prevented further loss in growth potential.

Craniomandibular dysfunction in children treated with total-body irradiation and bone marrow transplantation

The prevalence of pain and dysfunction in the stomatognathic system was studied in a group of 19 long-term survivors after pediatric bone marrow transplantation (BMT), conditioned with total-body irradiation (TBI). Compared with the control group, the children and adolescents in the BMT group had a significantly reduced mouth opening capacity. A reduced translation movement of the condyles was diagnosed in 53% of children treated with TBI, compared with 5% in the control group. Signs of craniomandibular dysfunction were found in 84% of children in the BMT group, compared with 58% in the control group. Both irradiation and chemotherapy induce long-term alterations in connective and muscle tissues resulting in inflammation and eventually fibrosis. These changes in tissue homeostasis and concomitant growth retardation may lead to the observed malocclusion and reduced mobility of the temporomandibular joint, with subsequent muscle pain and headaches, which were found in this study.

Allogeneic bone marrow transplantation following busulfan-cyclophosphamide with or without etoposide conditioning regimen for patients with acute lymphoblastic leukaemia

We have investigated the feasibility and efficacy of administering a radiation-free preparative regimen in the setting of allogeneic bone marrow transplantation (BMT) in 40 consecutive patients with acute lymphoblastic leukaemia (ALL). Busulfan (4 mg/kg/d x 4 d) and cyclophosphamide (50 mg/kg/d x 4 d) (BuCy4) were given in 29 patients and 11 received busulfan (4 mg/kg/d x 4 d), etoposide (60 mg/kg) and cyclophosphamide (60 mg/kg/d x 2 d) (BuCy+VP - 16). Median age was 22 years (range 1-50); 11 patients were children < or = 15 years of age. All children and 20 adults were at high risk of relapse pretransplant. Nine adults and one child died from transplant-related toxicity. 11 patients relapsed at a median of 11 months post-transplant (range 2-27). The 3-year Kaplan-Meier estimated probability of relapse was 42.1% and found to be significantly lower in patients with chronic GVHD (P = 0.03). 19 patients are leukaemia-free survivors with a median follow-up of 33 months (range 7-59). The Kaplan-Meier actuarial probability of disease-free survival at 3 years was 43% for all patients. 63.6% for children versus 30.2% for adults (P = 0.24) and 51.6% for patients transplanted in first remission versus 30.2% for those transplanted in subsequent remissions (P = 0.20).

Long-term complications following bone marrow transplantation in children

Seventeen children who underwent bone marrow transplantation (BMT) between 1975 and 1985 and survived for more than 2 years were evaluated for growth and development. The patients had a follow up of 2.1-13.1 years. Prior to transplant, children with malignancy had received multi-agent chemotherapy and nine had also received central nervous system irradiation. Transplant preparation for malignancy (group 1; n = 13) included high-dose cyclophosphamide (CPA) 120-200 mg/kg and total body irradiation (TBI) 10-13.2 Gy, whereas conditioning for non-malignant disorders (group 2; n = 4) included high-dose CPA 200 mg/kg with or without busulphan. Patients in group 1 showed a steady decline in height velocity following initial chemotherapy and cranial irradiation and the decline was even greater following BMT. Growth hormone (GH) deficiency developed in eight of nine children tested, hypergonadotrophic hypogonadism developed in 11 who reached puberty, thyroid hormone abnormalities were encountered in four out of 10 tested and 11 of 13 developed cataracts. Patients in group 2 did not show decline in linear growth rate, thyroid hormone abnormalities or cataracts after BMT. The only child tested had normal GH levels and the two patients who reached puberty showed delayed but complete gonadal recovery. Our data demonstrate that TBI leads to significant late effects on growth and gonadal function. Contrary to previous reports, a high incidence of cataract formation is observed after fractionated TBI. Conditioning regimens TBI should be considered in children undergoing BMT.

Growth and growth hormone secretion after bone marrow transplantation

This study analyses the growth and the growth hormone secretion of children given various conditioning protocols before bone marrow transplantation (BMT). Twenty nine children (14 boys, 15 girls) given BMT were classified according to their conditioning protocol: total body irradiation (TBI) given as a single exposure of 10 Grays (Gy, group I, 11 cases), or 8 Gy (group II, four cases), 12 Gy given as six fractionated doses (Group III, seven cases), or chemotherapy alone (group IV, seven cases). The arginine-insulin stimulated growth hormone peak, 2-7.5 years after BMT, was > 10 micrograms/l in all patients except four from group I (6.9-8.9 micrograms/l). A second growth hormone secretion evaluation was performed in 10 group I patients because of persistent low growth velocity despite a normal growth hormone peak. There were no significant changes in the mean (SEM) stimulated growth hormone peak (18.4 (2.2) v 20.1 (3.6) micrograms/l) at 3 (0.3) to 5.2 (0.6) years after BMT. The sleep growth hormone peaks and concentrations (n = 6) were normal. The mean cumulative height changes (SD) during the three years after BMT were: -1.4 (0.2) in group I, -0.1 (0.4) in group II, -0.4 (0.2) in group III, and 1.5 (0.5) in group IV; this was significant in groups I and IV. The final heights of two monozygotic twins (BMT donor and recipient) had differed by 17.5 cm, despite them both having normal growth hormone peaks and puberty. Eight patients, treated for congenital immune deficiency syndrome, were growth retarded at the time of BMT. Of these, only those conditioned by chemotherapy alone had significant catch up growth (2(0.6)SD) while those conditioned by a single Gy exposure did not (0(0.4)SD). It is concluded that the total radiation dose is critical for growth evolution, as is the fractionation schedule. For the TBI doses and the interval since BMT studied, there was no correlation between growth hormone peak and the height loss. The rapidity of decreased growth velocity after TBI and the comparison between the monozygotic twins suggest that radiation induced skeletal lesions are partly responsible for the decreased growth.

Growth and growth hormone secretion in children after bone marrow transplantation

Long-term sequelae of bone marrow transplantation (BMT) are a major concern among long-term survivors since the procedure has been considerably developed over the past decade. In this study, linear growth and growth hormone (GH) secretion were evaluated in 25 children (14 males and 11 females) with various neoplastic or non-neoplastic hematological disorders who had survived for more than 3 years after BMT. Impaired linear growth after BMT, as defined by a change in height standard deviation score (SDS) by more than -1.0 SD, was observed in 14 patients (56%). Four children showed severe growth suppression with a decrease in SD score by more than 2.0, and 10 exhibited a moderate reduction by between 1.0 and 2.0 SD. A recovery of normal height velocity was observed in those who had received BMT at a younger age. The type of disease, a difference in preconditioning regimen, the presence of chronic graft-versus-host disease or a GH secretory capacity 1 year after BMT were not contributing factors for impaired growth. A serial examination of GH secretion with insulin-induced hypoglycemia demonstrated that poor GH secretion was not necessarily a prerequisite for impaired growth. These results indicate that the secretory status of GH does not predict the future growth pattern of children who received BMT.

Autologous bone marrow transplantation in children with acute lymphoblastic leukemia

We report 25 children with acute lymphoblastic leukemia (ALL) treated with purged autologous bone marrow transplantation (ABMT) at a single center. Two children with high-risk ALL were transplanted in first remission and 23 with relapsing ALL were transplanted in second (n = 21) or third (n = 2) remission. There was no procedure-related mortality. The median time to engraftment (i.e. to reach a polymorphonuclear cell count of 0.5 x 10(9)/l) was 25 days (range 16-45 days). Seven children relapsed, four within five months after ABMT: 18 of 25 children (72%) are in continuous complete remission after a median follow-up period of 50 months (range 5-71 months). The predicted long-term disease-free survival is 65% in the whole group and 61% in those transplanted after relapse. Relapse-free children returned to normal activities within three months after ABMT. The major side effects were development of cataract and gonadal insufficiency. We consider the results promising, but our data do not allow comparison with results reported from treatment with chemotherapy alone, since some of our patients were referred from other centers and represent a selected patient group. Long-term follow-up of well-defined patient populations is necessary to evaluate the effect of ABMT.

Endocrine deficit after fractionated total body irradiation

Endocrine function was assessed in 31 children (17 boys) after fractionated total body irradiation used in the preparative regimen for bone marrow transplantation. Endocrine dysfunction was present in 25 children. Fifteen of 29 had growth hormone insufficiency 0.9-4.9 years after total body irradiation, yet only three of the 15 had received previous cranial irradiation. Five of 30 had thyroid dysfunction: two with a low thyroxine and raised thyroid stimulating hormone (TSH) concentration and three with a raised TSH and normal thyroxine concentration. Thus the incidence of thyroid dysfunction (16%) is much lower than that reported after single fraction total body irradiation (39-59%). In only two children were abnormalities of the hypothalamic-pituitary-adrenal axis demonstrated. The majority of pubertal children assessed (n = 15) showed evidence of gonadal damage. All the pubertal girls (n = 5) had ovarian failure, although there was evidence of recovery of ovarian function in one girl. All seven boys in late puberty showed evidence of damage to the germinal epithelium, and two of three in early puberty had raised follicle stimulating hormone concentrations. Despite the use of a fractionated total body irradiation regimen, endocrine morbidity is substantial and children undergoing such procedures will require long term endocrine review and management.

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.

Craniofacial growth in bone marrow transplant recipients treated with growth hormone after total body irradiation

The effect of growth hormone (GH) treatment on craniofacial development was studied in five children exhibiting growth retardation following bone marrow transplantation. Linear and angular measurements were made on lateral radiographic cephalograms taken prior to the start of GH treatment and after an average treatment time of 1.2 yr. The results showed that the mean growth increments of mandibular length in the GH treated children, exceeded the corresponding values of the control group by 150% during the period of investigation. It is suggested that this dimensional increase in the patients was due to GH stimulation on the chondral growth process in the mandibular condyles.

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.