Failure of hyperfractionated radiotherapy to reduce bone growth arrest in rats

PURPOSE

Radiotherapy of the craniospinal axis is causing an age dependent growth arrest in children. The purpose of this paper was to examine in an animal model, whether hyperfractionated radiotherapy, given with twice daily fractions in conventional overall treatment time, would cause less growth arrest of the spinal column than a regular treatment schedule.

METHODS AND MATERIALS

The time-dose-fraction schedule for the treatment of the craniospinal axis of children with medulloblastomas was used as model for the treatment of the spine in rats. The entire spine of weanling rats received either 3570 cGy in 21 daily fractions of the 170 cGy, 5 times per week over 27 days, or 3630 cGy in 33 fractions of 110 cGy, given twice daily with 6-hr intervals over 21 days.

RESULTS

Both fraction schedules were isoeffective and caused a growth inhibition of 9.5%. The growth arrest was complete after 1870-2420 cGy. The alpha/beta ratio for the growing rat vertebrae was 3400 cGy. This result contrasts with the growth sparing effect observed with hyperfractionation of accelerated treatment schedules.

CONCLUSION

Growing bone is a fast proliferating tissue. Hyperfractionation with 110 cGy BID compared to 170 cGy given once a day, has no sparing effect on bone growth in rats if given in conventional overall treatment time.

[Physical development in patients with acute lymphoblastic leukemia in childhood]

Acute lymphoblastic leukaemia (ALL) is one of the readily treatable neoplastic diseases of childhood. One of the late sequelae of treatment can be impaired growth. The authors followed up therefore a group of 63 patients where during childhood a diagnosis of ALL was made. The investigated group was treated according to two fundamental protocols--according to Pinkel's protocol and according to BMF protocols. All patients treated according to Pinkel's protocol had, as part of prevention of leukaemia of the CNS, radiotherapy of the skull, patients treated according to the BMF protocol only when the risk factor was higher than 0.8. The authors investigated in their patients the height and proportionality after termination of all antileukaemic therapy. They found that the height of children, adolescents and adults who suffered from ALL during childhood is average or less. A tendency towards obesity is typical. The authors did not observe a correlation with the total cumulative doses of cytostatics nor a marked correlation with radiotherapy. Impaired growth was more frequent when ALL was diagnosed before the age of 3 years and where the interval after completed therapy was shorter.

Long-term effects of treatment for acute lymphoblastic leukemia with and without cranial irradiation on growth and puberty: a comparative study

We investigated the comparative effect on long-term growth of CNS prophylactic treatment for acute lymphoblastic leukemia (ALL) with either 25-Gy cranial irradiation or moderate-dose i.v. methotrexate. In 80 children with complete continuous first remission, data on growth and pubertal development were investigated up to 11 y from ALL diagnosis. Forty patients had 25-Gy cranial irradiation, 16 of them with high-risk factors and 24 without. Another 40 non-high-risk ALL patients had moderate-dose methotrexate. Chemotherapy lasted 3 1/4 y for high-risk ALL patients and 2 1/4 y for those not at high risk. Pubertal development and final height were assessed separately for girls diagnosed before or after age 7 and for boys before or after age 9. All patients had a similar decline in height SD score during the first 6 mo of treatment, which persisted in irradiated children only. The nonirradiated group had no further decline. Catch-up growth only started when chemotherapy ended for irradiated and non-irradiated patients alike. Five y after cessation of treatment, changes in height SD score for nonirradiated children remained within the range for healthy children against a significant decline in height SD scores for irradiated children. Pubertal development in irradiated girls diagnosed before age 7 was within normal range, but their final height was disappointing due to a blunted growth spurt. In contrast, irradiated girls diagnosed later had a delayed onset of puberty but satisfactory final height. Comparable results were found in boys.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

A longitudinal study of growth and development of stature among prenatally exposed atomic bomb survivors

Growth retardation due to exposure to the atomic bomb has been evaluated using repeated measurements of stature from 10 to 18 years of age. A highly significant growth retardation due to the DS86 uterine dose was observed in all trimesters combined and in the first and second trimesters of pregnancy. In the first trimester, all parameter estimates based on a linear (L) or linear-quadratic (L-Q) dose-response relationship were negative in relation to the DS86 uterine dose. The positive dose estimate in the second trimester is small and close to the control level. Statistically significant difference was determined by a multivariate test statistic examining whether or not a set of two- or three-parameter estimates including a constant term related to an L or L-Q dose-response relationship was different from zero. A radiation-related growth retardation was demonstrable as a longitudinal result of the repeated measurements of stature. The dose effect in the third trimester was not significant under either the L or the L-Q model. The relationship between birth weights and repeated measurements of stature in adolescence is discussed based on the results obtained by a growth curve analysis.

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.

Biological effects of extremely low-frequency electromagnetic fields: in vivo studies

This paper discusses the biological effects of exposure to extremely low frequency electromagnetic fields observed in animal studies. Three areas of investigation are reported: (1) studies on the nervous system, including behavior and neuroendocrine function; (2) experiments on cancer development in animals; and (3) measurements of currents and electric fields induced in animal models by exposure to external magnetic fields. An attempt is made to evaluate experimental results and interpret them with respect to potential health implications.

Magnetic resonance imaging of the pituitary area in children treated for acute lymphoblastic leukemia with low-dose (18-Gy) cranial irradiation. Relationships to growth and growth hormone secretion

OBJECTIVE

To determine the effects of 18-Gy cranial irradiation on growth, growth hormone (GH) secretion, and pituitary magnetic resonance imaging in children who underwent previous irradiation for treatment of acute lymphoblastic leukemia.

DESIGN

Clinical survey.

SETTING

Department of Pediatrics of the University of Bologna (Italy).

PATIENTS

Ten boys and 18 girls who were treated for acute lymphoblastic leukemia; median age at diagnosis was 3.1 years and at the end of follow-up was 11.5 years.

MEASUREMENTS AND RESULTS

Height was periodically measured from diagnosis until the end of follow-up, when GH secretion study and magnetic resonance imaging were performed. The mean height SD score was significantly lower than at diagnosis only at the end of treatment. Nocturnal mean GH concentration and GH response to pharmacological tests (arginine and levodopa [L-dopa]) were pathological in 22 cases (81.5%) and 18 cases (64.3%), respectively. Sixteen cases (59.2%) had a blunted GH release to the three tests. Mean pituitary anterior lobe height was reduced and seven subjects (25%) showed an empty sella.

CONCLUSIONS

Cranial irradiation with 18 Gy does not seem to influence the growth pattern of most children who are treated for acute lymphoblastic leukemia, despite severe impairment of GH secretion and morphological abnormalities of the sellar area. However, a follow-up until final height is necessary.

The effects of adjuvant chemotherapy on growth in children with medulloblastoma

BACKGROUND

Current therapy for children with medulloblastoma includes craniospinal radiation therapy (CSRT) with or without adjuvant chemotherapy. The difference in growth of children after the two different therapeutic modalities is unknown.

METHODS

The growth of 38 prepubertal children who survived medulloblastoma was reviewed retrospectively. Fifteen of these patients received CSRT alone; 23 received chemotherapy in addition to the radiation therapy.

RESULTS

The average growth velocity of all patients with medulloblastoma during the 4 years of the study was below the mean for age and sex in all patients except one. Most patients grew at velocities more than two standard deviations below the mean. The overall growth of children who received chemotherapy in conjunction with CSRT was significantly worse than the growth of those who received only CSRT. The children who received chemotherapy showed little or no improvement in growth velocity by year 4; those who did not receive chemotherapy had some improvement.

CONCLUSIONS

These findings suggest that chemotherapy potentiates the deleterious effects of radiation on growth.

Late effects following central nervous system radiation in a pediatric population

Between 1970 and 1986, 120 children with central nervous system malignancy were treated with radiation therapy. These included 44 low-grade astrocytomas, 11 high grade astrocytomas, 32 medulloblastomas, 15 ependymomas/ependymoblastomas, 3 primitive neuroectodermal tumors and 8 pineal tumors. Seven children were treated without biopsy. Fifty-one treated children were evaluated for the effects of therapy on growth, endocrine function, IQ and hair regrowth. Mean height was 1.5 standard deviations below the mean height for the patient's age at study (range 0-5.7). Height was significantly less in patients receiving radiation to the pituitary and those with somatomedin-C deficiency. Height was also decreased with whole CNS radiation and spine dose > 20 Gy but not to a significant degree. Pituitary radiation in any dose increased the chance of endocrine deficiency (p = 0.004) and 21 of 51 patients had somatomedin-C deficiency. Mean IQ was 92.7 (+/- 18.8), with a slight trend toward decreased IQ with increasing whole brain dose of radiation. Hair regrowth was complete in 20 of 46 evaluated patients, diminished regrowth occurring with increasing volume and dose of radiation. No difference in the measured late effects could be detected with respect to age at treatment, sex, histology or location of tumor.

[Evaluation of the effect of the radioactive contamination of hydrobionts in the 30-kilometer control zone of the accident at the Chernobyl AES]

A study was made of hydrobionts, particularly fishes, living within the thirty-kilometer control zone of Chernobyl NPP and northern part of the Kiev basin, after the disaster. Out of 31 fish species living in the NPP cooling pond some were identified which were mostly affected by radioactive contamination. They were predators belonging, with respect to reproduction and development, to a lithophilous group. Peculiarities of reproduction of Hypophthalmichthys molitrix kept in stews of the cooling pond before the accident were studied. After a three-year exposure to ionizing radiation (cumulative dose of 8-9 Gy) no reduction in the reproductive capacity of mature fishes was observed.

[The effect of the dose rate on the development of rat pups under chronic gamma irradiation]

Chronic exposure of rat pups to gamma radiation, during their intensive growth, at a dose rate of 0.01, 0.11 and 0.5 cGy/day did not affect their development throughout a two-month period of observation. At a dose rate of 12.9 cGy/day rat growth was inhibited during the first 15 days. With further exposure at the same dose rate (over a period of up to five months) the rate of rat pup growth was restored, which indicated the presence of adaptation processes.

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.

Growth after radiotherapy and chemotherapy in children with leukemia or lymphoma

The effect of radio- and chemotherapy on auxological parameters was investigated in 30 children treated for acute lymphatic leukemia (ALL) or non-Hodgkins lymphoma (NHL). Growth velocity was decreased during the first year of treatment. Catch-up growth was insufficient during the following years. Thus, the whole group experienced a loss of height of 0.49 +/- 1.1 SD at 6.8 +/- 2.6 years after diagnosis. Height and growth velocity were not different between children who received 18 or 24 Gy cranial irradiation; however, growth velocity was significantly lower in children who were treated for more than 2 years or who had the more intensive chemotherapeutic protocol. Evaluation of the growth hormone (GH) response to pharmacological stimulation revealed reduced GH peaks in 47% of the patients, but there was no correlation of GH peak with growth or treatment parameters. In conclusion, the impairment of growth in children after treatment for ALL or NHL might be related to the intensity and duration of chemotherapy.

Longitudinal anthropometric study in children with acute lymphoblastic leukaemia

In four groups of patients with acute lymphoblastic leukaemia, anthropometric variables were investigated every 3 months for 2 years. Group 1 (n = 7) was treated with a high-risk protocol, group 2 (n = 13) with a standard-risk protocol including cranial irradiation, group 3 (n = 13) with a standard-risk protocol without cranial irradiation and group 4 (n = 8) was followed after completion of treatment. A height retardation of 0.4-0.6 SD was observed during therapy in groups 1-3. A catch-up of 0.5 SD was found in group 4. The retardation of armspan was significantly larger than the retardation of sitting height when groups 1-3 were taken together. Head circumference was not affected. The anthropometric variables reflecting nutritional status showed a growth above normal during and after treatment. Corticosteroid medication and not cranial irradiation is the most likely explanation for our findings.

Photochemical effects of laser irradiation on neuritic outgrowth of olfactory neuroepithelial explants

The photochemical effect of low-intensity laser irradiation (LILI) on the maturation and regeneration of olfactory-immature estrus day 15 (E15) and olfactory-mature estrus day 22 (E22) rat fetuses was studied. Neuritic outgrowths of olfactory bipolar receptor cells were quantified in olfactory neuroepithelial explants. Explants in the experimental groups were irradiated with a helium-neon laser using different incident energy densities (IEDs). Explants in another group were exposed to fluorescent light. Control explants did not receive laser or fluorescent light irradiation. Neuritic outgrowths were analyzed on a regular basis for 12 days. Analysis of variance was used to evaluate the data. The parameters of neuritic outgrowth in E15 fetuses showed a significant increase of 30% to 50% vs. the control with a single laser irradiation of 0.5 J/cm2 IED. The rate of neuritic outgrowth observed in the E22 fetuses was less than in the E15 fetuses. The parameters of neuritic outgrowth in E22 fetuses showed a significant and substantially greater percentage increase than in the E15 fetuses with daily laser irradiations of 0.05 and 0.5 J/cm2 IED when compared to the control. The magnitude of these increases appears to be of biological significance as well as statistical significance.

[The biological effects in animals related to the accident at the Chernobyl Atomic Electric Power Station. 6. The physiological development and cytogenetic indices of the progeny of rats]

Certain alterations have been revealed in the postnatal ontogenesis parameters of albino mongrel rats and their descendants constantly kept within the thirty-kilometer zone of the Chernobyl A.P.S. Structural disturbances have been found in bone marrow cell chromosomes.

Prenatal exposure to gamma/neutron irradiation: sensorimotor alterations and paradoxical effects on learning

The effects of prenatal exposure on gamma/neutron radiations (0.5 Gy at about the 18th day of fetal life) were studied in a hybrid strain of mice (DBA/Cne males x C57BL/Cne females). During ontogeny, measurements of sensorimotor reflexes revealed in prenatally irradiated mice 1) a delay in sensorial development, 2) deficits in tests involving body motor control, and 3) a reduction of both motility and locomotor activity scores. In adulthood, the behaviour of prenatally irradiated and control mice was examined in the open field test and in reactivity to novelty. Moreover, their learning performance was compared in several situations. The results show that, in the open field test, only rearings were more frequent in irradiated mice. In the presence of a novel object, significant sex x treatment interactions were observed since ambulation and leaning against the novel object increased in irradiated females but decreased in irradiated males. Finally, when submitted to different learning tasks, irradiated mice were impaired in the radial maze, but paradoxically exhibited higher avoidance scores than control mice, possibly because of their low pain thresholds. Taken together, these observations indicate that late prenatal gamma/neutron irradiation induces long lasting alterations at the sensorimotor level which, in turn, can influence learning abilities of adult mice.

Results of a changing treatment philosophy for children with stage I Hodgkin's disease: a 35-year experience

Over the last four decades, significant changes have occurred in the management of childhood stage I Hodgkin's disease. Between 1949 and 1984, 50 children, ages 4 to 16 years, were treated for stage I Hodgkin's disease at The University of Texas M. D. Anderson Cancer Center. Nineteen children had clinically staged (CS) disease. Thirty-one patients were pathologically staged (PS). Thirty-four children were treated with radiotherapy only, 12 were treated with both radiotherapy and chemotherapy, and 3 patients were treated with combination chemotherapy alone. All patients were followed from 32 to 311 months (median 170 months). Five-, 10-, and 15-year actuarial survival rates for all patients were 94, 89, and 84%, respectively. The corresponding freedom from relapse (FFR) rates were 76, 69, and 69% respectively. The 10-year actuarial survival and FFR rates for CS patients were 79 and 42%. The corresponding rates for PS patients were 97 and 86%. In patients with PSI disease, actuarial 10-year FFR rates of 100% were obtained either with regional radiotherapy alone or with combination chemotherapy and involved field radiotherapy. The following delayed adverse effects of treatment were observed: growth abnormalities in 17, aspermia in 3, thyroid abnormalities in 11 (two carcinomas), and second malignancies beyond the radiotherapy fields in 2. We conclude with a recommendation of combined chemotherapy and involved field radiation for children who have not fulfilled their growth potential, to achieve high cure rates, while minimizing morbidity.

A longitudinal study of growth and growth hormone secretion in children during treatment for acute lymphoblastic leukemia

Diminished growth rate during treatment for acute lymphoblastic leukemia (ALL) is of the multifactorial etiology. Effects on GH secretion have been shown after discontinuation of treatment including prophylactic CNS irradiation. Seventeen children treated for ALL with three different CNS preventive schedules were followed longitudinally with repeated estimations of the spontaneous GH secretion during a 24-month period. No difference was found in GH secretion during this time between patients who had received no radiotherapy and those who had received 18 or 24 Gy as CNS prophylaxis. During dexamethasone treatment the GH secretion was completely suppressed, which can be a mediator for the diminished growth rate during the first 2 years of ALL treatment. We conclude that there is no clinical reason to perform GH analysis within the first 24 months of treatment for ALL.

Longitudinal growth in children with non-Hodgkin's lymphoma and children with acute lymphoblastic leukemia: comparison between unirradiated and irradiated patients

Longitudinal growth was studied in children treated for non-Hodgkin's lymphoma (NHL). The aim of the study was to compare these children's growth velocity with findings in a previous study we performed on age-matched children with acute lymphoblastic leukemia (ALL) who received cranial irradiation. Nine children with NHL with an onset time of treatment between 4 and 9 years of age (mean 6.5 years) were studied with annual body measurements taken from the time of the diagnosis and thereafter annually during the following 4 years. None of the children received cranial irradiation. During the first treatment year a significantly low mean height velocity was observed (-1.4 standard deviation score [SDS]) for the NHL group. The consecutive two 1 year periods showed a normalization of the mean height velocity. For the group of children with ALL, there was a more prominent negative effect on height during the first 2 years of treatment than for the NHL group in the present study. After the cessation of therapy, the children with NHL showed a reduced catch-up growth compared with the children with ALL. The explanation offered is that cranial irradiation has a heavier impact on growth than chemotherapy during the first 2 years of treatment, but an intense chemotherapy during the maintenance period could have a considerable impact in blunting growth.

An animal model to study toxicity of central nervous system therapy for childhood acute lymphoblastic leukemia: effects on growth and craniofacial proportion

Many long term survivors of childhood acute lymphoblastic leukemia have short stature, as well as craniofacial and dental abnormalities, as side effects of central nervous system prophylactic therapy. An animal model is presented to assess these adverse effects on growth. Cranial irradiation (1000 cGy) with and without prednisolone (18 mg/kg i.p.) and methotrexate (2 mg/kg i.p.) was administered to 17- and 18-day-old Sprague-Dawley male and female rats. Animals were weighed 3 times/week. Final body weight and body length were measured at 150 days of age. Femur length and craniofacial dimensions were measured directly from the bones, using calipers. For all exposed groups there was a permanent suppression of weight gain with no catch-up growth or normal adolescent growth spurt. Body length was reduced for all treated groups, as were the ratios of body weight to body length and cranial length to body length. Animals subjected to cranial irradiation exhibited microcephaly, whereas those who received a combination of radiation and chemotherapy demonstrated altered craniofacial proportions in addition to microcephaly. Changes in growth patterns and skeletal proportions exhibited sexually dimorphic characteristics. The results indicate that cranial irradiation is a major factor in the growth failure in exposed rats, but chemotherapeutic agents contribute significantly to the outcome of growth and craniofacial dimensions.

The effects of X irradiation on the metamorphosis and budding of Aurelia aurita

With the aid of the Aurelia metamorphosis test system, the acute and subtle developmental and behavioral effects of X irradiation in the presence and absence of thyroxine on the Norfolk Aurelia aurita were described. Radiation doses were 0 (control), 50, 100, 150, 200, and 400 Gy. Morphology of the ephyrae, and statolith and rhopalia numbers were recorded using the light microscope. Developmental abnormalities of the polyps and ephyrae were recorded with the scanning electron microscope and light microscope. Major findings from this investigation were the absence of rhopalia and statoliths in ephyrae at 150 and 200 Gy, a reduction in pulses per minute in the ephyrae at 100, 150, and 200 Gy, a reduction in ephyrae released at 150, 200, and 400 Gy, and the development of polyp monsters. There was a significantly higher frequency of polyp monsters in the group exposed to thyroxine prior to radiation than in the thyroxine-free group prior to radiation.