Disorders of the endocrine system due to radiation and cytotoxic chemotherapy

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

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

Thyroid Sequelae of Pediatric Cancer Therapy

The hypothalamic-pituitary-thyroid axis is a common site of unintended, acquired disease either during or after the treatment of cancer. Children treated with external radiation therapy are at the highest risk for developing a thyroid-related late effect, but thyroid dysfunction and second primary thyroid neoplasms can also occur after treatment with radiopharmaceutical agents such as 131I-metaiodobenzylguanidine. Increasingly recognized is the development of early thyroid dysfunction as an off-target consequence of the more novel cancer therapeutics such as the tyrosine kinase inhibitors and immune checkpoint inhibitors. Thyroid sequelae resulting from irradiation may manifest only after years to decades of follow-up, and their resultant clinical symptoms may be indolent and non-specific. Therefore, lifelong monitoring of the childhood cancer survivor at risk for thyroid disease is paramount. In this comprehensive review, the myriad thyroid adverse effects resulting from pediatric cancer treatment are discussed and an overview of screening and treatment of these thyroid sequelae provided.

Effects of cancer treatment on ovarian function

Causes of primary ovarian failure are reviewed, focusing specifically on cancer treatment-related modalities. Strategies and future directions for protection of the ovaries during cancer therapy, including ovarian transposition, and conformal radiation techniques are presented.

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

BACKGROUND

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

REVIEW SUMMARY

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

CONCLUSIONS

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

Thyroid diseases in patients treated during pre-puberty for medulloblastoma with different radiotherapic protocols

We evaluated thyroid disease in 32 patients treated, during pre-puberty, for medulloblastoma, followed for at least 4 years and without relapse during observation. After surgery the patients underwent chemotherapy (CT) and radiotherapy (RT). The protocols were as follows: 20 patients (group A) SNC 76 and SNC 85 protocols which included conventional fractionated RT (36-40 Gy to the craniospinal axis and a 14-18 Gy boost to the posterior fossa, administered as 1.5-1.8 Gy per fraction per day) and a junction between the cranial and the spinal fields at C2-C3 level; 12 patients (group B) SNC 91 protocol which included hyperfractionated RT (36 Gy to the craniospinal axis and a 30 Gy boost to the posterior fossa; this was administred as 1 Gy per fraction twice per day) and a junction at levels C5-C6 or C6-C7 level. The mean age at diagnosis was 7.4+/-3.2 years for group A and 8.4+/-2.6 years for group B. Thyroid function was evaluated yearly and ultrasonographic characteristics every 2 years. The patients were followed for a mean of 10.8+/-3.8 for group A and 6+/-1.4 years for group B. Primary hypothyroidism was diagnosed in 16 group A patients and 4 group B patients, and central hypothyroidism was diagnosed in 2 group A patients (difference in risk of developing hypothyroidism evaluated with a Wilcoxon-test: p=0.048). Ultrasonography showed reduced thyroid volume in 7 group A cases, and structural changes in 21 patients (17 group A, 4 group B); 9 L-thyroxine-treated patients were confirmed hypothyroid after having stopped therapy. A thyroid nodule was detected in two cases (one from each group). In conclusion, our data indicate that thyroid injury may be diminished by the use of hyperfractionation and low-junction radiotherapy in the treatment of medulloblastoma.

The effect of chemotherapy on the growing skeleton

With the increasing use of high dose (poly)chemotherapy schedules in the treatment of childhood cancer it is particularly important to know the adverse effects of these treatments. Growth is a complex mechanism affected not only by chemotherapy but also by the malignancy itself as well as nutritional status, the use of corticosteroids and (cranial) radiation. In vitro and animal studies are often the most useful in determining the effect of a single chemotherapeutic agent on the growing skeleton. In vitro studies have shown doxorubicin, actinomycin D and cisplatin to have a direct effect on growth plate chondrocytes that in animals results in decreased growth and final height. Clinical studies with multiagent chemotherapy have demonstrated that antimetabolites decrease bone growth and final height. Childhood cancer survivors are at risk of a reduced bone mineral density, mainly due to methotrexate, ifosfamide and corticosteroids. This reduced bone mineral density persists into adult life and may increase bone fracture risk at an older age.

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.

Osteopenia in young adult survivors of childhood cancer

BACKGROUND

Improved survival of children with malignant diseases is in part due to the application of intensive, multimodality therapies, including radiotherapy, surgery, glucocorticoids, and cytotoxic agents. Such interventions have the potential to induce complex hormonal, metabolic and nutritional effects that may interfere with skeletal mass acquisition during childhood and adolescence: it is possible that such childhood cancer survivors may therefore reach adulthood with diminished peak bone mass and be at increased risk for clinically significant osteoporosis later in their life.

PROCEDURE

A bone mineral density (BMD) was measured in 26 unselected former cancer patients attending the Pediatric Long-Term Clinic at M.D. Anderson Cancer Center. BMD was measured at the lumbar spine and the hip using dual X-ray absorptiometry (Hologic QDR-4500W). In addition, the patients' complete medical records were reviewed with particular attention to disease type, age modalities of treatment, and hormonal residual deficiencies.

RESULTS

The median age of patients at the time of cancer diagnosis was 8 years (range, 0.3 to 16 years). Median age at BMD determination was 23 years (range, 18 to 41 years), and the median interval since cancer diagnosis and BMD was 18 years (range, 5 to 29). Overall, their BMD was decreased relative to peak bone mass at all sites: osteopenia was especially pronounced in patients with a history of cranial irradiation who had developed evidence of pituitary insufficiency during childhood or adolescence. Overall, the median BMD T-score was -1.41 at the lumbar spine, -1.04 at the femoral neck, and -1.06 for total hip. For patients with prior cranial irradiation, T-score at the lumbar spine was -2.18 (range, -4.06 to -0.98), at the femoral neck -1.92 (range, -4.11 to +1.10), and for total hip -1.67 (range, -4.79 to +0.56); BMD for irradiated patients was significantly lower than BMD of patients without cranial irradiation. We could not discern an independent impact of other disease characteristics or treatment modalities in this small group of patients.

CONCLUSIONS

Osteopenia is a prominent finding in young adults who are survivors of childhood cancers; it is likely that antineoplastic treatments during childhood and adolescence impede peak bone mass acquisition. We suggest that systematic attention to this potential complication is needed in order to identify what subgroups of children may require regular surveillance and what interventions are required for its prevention or treatment.

The monitoring of potential long-term comlications in treated adult cancer patients

A wide variety of long-term complications may be noted following conventional cancer treatment. These include overwhelming postsplenectomy sepsis syndrome, central and peripheral nervous system toxicity, cardiovascular complications, chronic liver damage, and secondary malignancy. Follow-up monitoring usually incorporates both physical examination and the result of radiological and laboratory investigations. Primary care physicians will often be responsible for the majority of the follow-up monitoring involving cured cancer patients and need to be aware of possible long-term therapy-related problems, especially those that present years after successful treatment of the original malignancy.

Endocrine function and bone metabolism 5 years after autologous bone marrow/blood-derived progenitor cell transplantation

BACKGROUND

High dose chemotherapy with or without total body irradiation supported by autologous transplantation of hematopoietic progenitor cells is increasingly being used for hematologic and solid tumors. However, there is only limited information available on late toxicity.

METHODS

The authors investigated endocrine function and bone metabolism in 29 patients with a median interval of 5 years after autografting.

RESULTS

In accordance with an earlier report on this patient cohort, ovarian failure was observed to be unchanged, except for one woman with recovered ovarian function who gave birth to two healthy children. In two-thirds of the men, follicle-stimulating hormone levels were elevated, suggesting germinal aplasia. Determination of bone mineral density did not reveal osteopenia, despite several risk factors: prolonged immobilization, high dose corticosteroid treatment, and, in women, transient estrogen insufficiency. Frequent impairment of thyroid function has been reported in patients receiving single dose total body irradiation. Overt or subclinical hypothyroidism was not detected, most likely because the total body irradiation was hyperfractionated.

CONCLUSIONS

With the exception of gonadal failure, no significant late effects on endocrine function or bone metabolism were observed in this patient cohort.

The effects of irradiation and chemotherapy on growth

The effects of cancer therapy on growth are reviewed. The effects of radiation and chemotherapy on growth hormone production and growth hormone responsiveness by peripheral tissues are examined. The effects of radiotherapy and chemotherapy on other endocrine function pertaining to growth also are discussed. An approach to surveillance of pediatric cancer survivors pertaining to growth and development is suggested.

Influence of treatment modalities on prepubertal growth in children with acute lymphoblastic leukemia

The statural growth of 85 prepubertal children treated for acute lymphoblastic leukemia was evaluated in a longitudinal study over 4.5 years. Patients were divided into three groups according to central nervous system prophylaxis: 37 patients received cranial irradiation with a dose of 24 Gy, 15 received a dose of 18 Gy, and 33 were not irradiated. According to the risk of leukemia, patients were divided into normal-risk (n = 74) and high-risk (n = 11) groups. The duration of treatment was 2 years, during which all patients showed growth retardation. The relative standard deviation score for height declined from 0 to -0.7 for the irradiated patients and from 0 to -0.2 for the non-irradiated group (P = 0.0001). There was no difference in growth pattern between cranial irradiation with 18 versus 24 Gy and chemotherapeutic treatment according to high-risk versus normal-risk protocols. However, a negative synergistic effect of more intensive chemotherapy and cranial irradiation on growth was demonstrated.

Late injury of cancer therapy on the female reproductive tract

The purpose of this article is to review the late effects of cancer therapy on the female reproductive tract. The anatomic sites detailed are the vulva, vagina, cervix, uterus, fallopian tubes, and ovaries. The available pathophysiology is discussed. Clinical syndromes are presented. Tolerance doses of irradiation for late effects are rarely presented in the literature and are reviewed where available. Management strategies for surgical, radiotherapeutic, and chemotherapeutic late effects are discussed. Endpoints for evaluation of therapeutic late effects have been formulated utilizing the symptoms, objective, management, and analytic (SOMA) format. Late effects on the female reproductive tract from cancer therapy should be recognized and managed appropriately. A grading system for these effects is presented. Endpoints for late effects and tolls for the evaluation need to be further developed.

Pubertal development in thalassaemic patients after allogenic bone marrow transplantation

To obtain further insight into gonadal function, a series of 50 prepubertal patients with beta-thalassaemia major (24 boys and 26 girls) aged from 12.6 to 18 years (mean 15 years) who had received a bone marrow transplantation (BMT) during childhood or the peripubertal period, at the age of 3.6-14.5 years (mean 10.8 years), were periodically re-evaluated at intervals of 6-12 months. The last evaluation was done 1-9 years (mean 4.2 years) after BMT. At each examination we measured height, pubertal stage, plasma gonadotrophins (LH and FSH) before and after the GnRH stimulation test (i.v.), sex steroids (total and free testosterone in males, and 17 beta-oestradiol in females), serum ferritin and bone age. Fourty percent of patients entered or passed through puberty normally despite clinical and hormonal evidence of gonadal dysfunction in most of them. A correlation was not found between the pubertal stage and age at BMT, and no statistical difference between patients who did not enter into puberty and patients with spontaneous pubertal development was found in serum ferritin levels. Our data confirm that gonads in male and female thalassaemic patients are exposed to the cytotoxic effects of the preparative transplant regime with alkylating agents. In some patients absence of pubertal development was due to gonadotrophin insufficiency, probably secondary to previous iron overload. These findings emphasize the need for a vigilant long-term follow up study of thalassaemic patients who have had BMT.

Growth in children after bone marrow transplantation for advanced neuroblastoma compared with growth after transplantation for leukemia or aplastic anemia

The linear growth of 26 children with progressive and advanced neuroblastoma treated with high-dose chemotherapy, total body irradiation, and bone marrow transplantation between 1978 and 1988 at the Children's Hospital of Philadelphia was compared with the growth of 33 children who had transplants for leukemia and of 12 who had transplants for aplastic anemia. The mean growth velocity, expressed as a standard deviation score, for the children who underwent bone marrow transplantation for neuroblastoma was -2.83. This was significantly (p less than 0.005) less than the standard deviation scores for children with transplants for acute lymphoblastic leukemia, acute nonlymphocytic leukemia, and aplastic anemia, which were -0.98, -0.07, and -1.05, respectively. A 6-year follow-up study of 32 long-term survivors of cancer revealed that the 11 patients with neuroblastoma continued to grow poorly, whereas a comparison group of 21 survivors of bone marrow transplantation for leukemia had essentially normal growth 2 years after the procedure. Major therapeutic differences between the two groups included the doses of local radiotherapy and the type and number of cytotoxic agents used. In comparison with the relatively mild growth-inhibiting effects of preparative regimens for leukemia and aplastic anemia, the very intensive preparative regimens used in patients with neuroblastoma have significant negative effects on growth.

Gonadal status and reproductive function following treatment for Hodgkin's disease in childhood: the Stanford experience

To ascertain the impact of therapy on gonadal function and reproductive outcome among children treated for Hodgkin's disease, we reviewed the experience at Stanford University Medical Center during the years 1965-1986. There were 240 children 15 years of age or younger, 92 girls and 148 boys; with median follow-up of 9 years, maximum follow-up was 26 years. Of this cohort, data on gonadal function were available on 20 boys, 5 of whom were considered prepubescent; they had no clinical evidence of sexual maturation and were less than 13 years of age. Evaluation of the boys included testicular biopsy, semen analyses and the ability to procreate. Serum gonadotropin hormone levels (FSH, LH) were studied in 11 boys who also had semen analyses. Sexual maturation was attained in all boys without the need for androgen replacement. Among the eight boys treated with radiation alone, four were able to father a child (3 following 40-45 Gy pelvic radiation dose, 1 without pelvic radiation) from 3-19 years following treatment. Three others who received 30-44 Gy pelvic radiation were oligospermic when tested at 10 to 15 years post-treatment. Semen analyses in 10 of 12 (83%) boys who had been treated with six cycles of MOPP with or without pelvic radiation revealed absolute azoospermia with no evidence of recovery as along as 11 years of follow-up. Following prolonged azoospermia, 2 of the 12 boys (17%) had recovery of fertility, with normalization of sperm count and/or ability to procreate at 12 and 15 years following treatment. There was no correlation with serum gonadotropin levels and sterility. Data on menstrual history, pregnancy and offspring were available in 86 (92%) of the girls. Seventy-five of the 86 girls (87%) have normal menstrual function. However, none of the females who underwent pelvic radiation without prior oophoropexy has maintained ovarian function. Both the prepubescent and postpubescent boys were affected by 6 cycles of MOPP whether or not pelvic radiation was administered. On the other hand, in girls similarly treated, ovarian injury was directly related to both the number of cycles of chemotherapy and the ovarian radiation dose. The chances of maintaining gonadal function following combined modality treatment are significantly greater among girls than boys. The progeny of patients treated for Hodgkin's disease appear normal and no excess fetal wastage has been noted.

Growth and endocrine disorders in optic glioma

Hypothalamo-pituitary function in children with optic glioma may be impaired by the tumour itself and by the high cranial radiation doses used in treatment. This study evaluates the effect of optic glioma and its treatment on patient growth and pubertal development. Twenty-one patients (13 boys, 8 girls), treated for optic glioma by cranial irradiation (45-55 Grays) at a mean age of 5.4 years, were evaluated before (n = 10) and/or after (n = 21) irradiation. Growth hormone (GH) deficiency was present in only 1 patient tested before irradiation and in all patients after irradiation. Precocious puberty occurred in 7/21 cases, before irradiation in 5 patients and after irradiation in 2 patients. The cumulative height loss during the 2 years after irradiation was 0.2 +/- 0.2 SD (m +/- SEM) in 7 patients with precocious puberty and 1.1 +/- 0.2 SD in 14 prepubertal patients (P less than 0.01). The corresponding bone age advance over chronological age, evaluated 1-3 years after irradiation, was 1.1 +/- 0.5 and -0.7 +/- 0.3 year in the two groups (P less than 0.01). The mean height loss between time of irradiation and the final height was 2.3 +/- 0.6 SD (n = 6). Primary amenorrhoea, associated with low oestradiol levels, occurred in two of the three girls of pubertal age. These data indicate that the high dose of cranial radiation used to treat optic glioma invariably results in GH deficiency within 2 years and that hGH therapy is required when GH deficiency is documented.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged suppression of spermatogenesis by oestrogen does not preserve the seminiferous epithelium in procarbazine-treated rats

We examined the hypothesis that induction of reversible testicular atrophy, subsequent to withdrawal of gonadotrophin support, would alleviate the testicular toxicity of the anti-cancer drug procarbazine. In rats, severe but reversible testicular atrophy and suppression of spermatogenesis were induced 56 days after the subcutaneous insertion of a silastic implant containing oestradiol-17 beta. The effect of this treatment upon the testicular toxicity of four weekly doses of procarbazine (200 mg kg-1) was examined 56 days after the termination of procarbazine/oestrogen treatment. At this time the testicular endocrine and spermatogenic functions were close to normal in rats which has received only oestradiol-17 beta. Procarbazine produced severe testicular atrophy which was associated with azoospermia and destruction of the germinal epithelium. Serum LH and FSH concentrations were raised and were associated with low serum concentrations of both testosterone and androgen-binding protein. The combination of procarbazine with the oestrogen treatment did not change any of the testicular toxicity and in some cases it appeared to be exacerbated. In contrast to these experiments other studies have indicated that the testis can be protected if spermatogenesis is reversibly suppressed by other agents which are also active via the pituitary endocrine system. The data would therefore suggest that protection is achieved either by some testicular change other than withdrawal of pituitary gonadotrophin support or that oestradiol-17 beta has additional activity which is permissive for the development of the testicular toxicity of procarbazine.

Response to growth hormone treatment and final height after cranial or craniospinal irradiation

Growth hormone (GH) deficiency (GHD) induced by cranial irradiation has become a frequent indication of hGH substitutive therapy. This study analyses the growth response to hGH therapy and the factors involved in the decrease in growth velocity observed after cranial irradiation. One hundred children (61 boys and 39 girls) given cranial radiation for pathology distant from the hypothalamo-pituitary area were studied. Fifty-six of them received hGH therapy for GHD resulting in decreased growth velocity. The initial annual height gain in the cranial-irradiated group was comparable to that of patients treated for idiopathic GHD; additional spinal irradiation significantly reduced the growth response. Twenty-eight hGH-treated patients reached final heights which were compared to those of 2 untreated irradiated groups, one with GHD (n = 27) and the other with normal GH secretion (n = 17). The height SD score changes observed in hGH therapy were +0.3 in the cranial (n = 10) and -1.2 SD in the craniospinal (n = 18) groups. GH deficiency had contributed to a mean height loss of 1 SD and spinal irradiation to a loss of 1.4 SD. The small effect of hGH therapy on final height is probably linked to the small bone age retardation at onset of hGH therapy and to the fact that irradiated children entered puberty at a younger age in terms of chronological age (10.6 +/- 0.3 yr in girls and 11.0 +/- 0.3 yr in boys) and bone age (9.6 +/- 0.4 yr in girls and 12.6 +/- 0.3 in boys) than the idiopathic GHD patients. These data suggest that the results of hGH therapy in irradiated children might be improved with higher and more fractionated hGH doses and, in some patients, by delaying puberty using luteinizing hormone releasing hormone analogs.

Pregnancy and offspring after adjuvant chemotherapy in breast cancer patients

A retrospective review of 227 consecutive breast cancer patients who were 35 years of age or younger and who had been given doxorubicin-containing adjuvant chemotherapy was conducted to determine the frequency of pregnancy and its effect on the clinical course of the disease. Also, the status of the newborn was evaluated. There were 33 pregnancies in 25 patients (10 pregnancies were terminated, 2 patients had spontaneous abortions, and 19 patients gave birth to full-term offspring without fetal malformation). Two patients were still pregnant at the time of this report. The median interval between the completion of chemotherapy and pregnancy was 12 months. Eight patients who became pregnant experienced temporary amenorrhea during chemotherapy. Of the 25 patients who became pregnant, recurrent disease subsequently developed in 7 and 3 died. A patient's disease-free and overall survival status was not adversely effected by pregnancy. These data illustrate that in a sizeable fraction of patients 35 years of age or younger treated with adjuvant doxorubicin-containing therapy, ovarian function remained intact and subsequent pregnancy did not affect the disease-free or overall survival of the patients.

Management of growth failure in the treatment of malignant disease

Growth failure due to endocrine dysfunction as a result of treatment for malignant disease is becoming increasingly common. It may occur after cranial or craniospinal irradiation given in the treatment of acute lymphoblastic leukemia and brain tumors, and is often coupled with early or precocious puberty. It also occurs after neck and gonadal radiation and is particularly severe after total body irradiation where multiple endocrine deficiencies frequently occur. Failure to appreciate its occurrence or failure to institute therapy early enough may lead to short stature in adult life. Accurate and regular monitoring of standing and sitting height, bone age, and endocrine data should be undertaken by the oncologist in close collaboration with an endocrinologist, to ensure appropriate management of the patient.

Ovarian failure following abdominal irradiation in childhood: the radiosensitivity of the human oocyte

Ovarian function has been studied sequentially since 1975 in 19 patients treated in childhood for an intra-abdominal tumour with surgery and whole abdominal radiotherapy (total dose 30 Gy). Eleven patients received chemotherapeutic agents that are not known to cause gonadal dysfunction. All but one patient have developed ovarian failure with persistently elevated gonadotrophin levels (FSH and LH greater than 32 IU/litre) and low serum oestradiol values (less than 40 pmol/litre) before the age of 16 years. The majority (n = 12) did not progress beyond breast stage 1 without sex steroid replacement therapy. As the number of oocytes within the ovary declines exponentially by atresia from approximately 2,000,000 at birth to approximately 2000 at the menopause, we have been able to estimate that the LD50 for the human oocyte does not exceed 4 Gy.

Ovarian failure following abdominal irradiation in childhood: natural history and prognosis

Ovarian function has been reviewed sequentially since 1975 in 53 patients treated in childhood between 1942 and 1985 for an intraabdominal tumour with surgery and external abdominal radiotherapy (XRT). Of 38 patients who received whole abdominal XRT (20-30 Gy), 27 failed to undergo or complete pubertal development (pubertal failure) and a premature menopause (median age 23.5 years) occurred in a further ten. Of 15 patients who received flank XRT (20-30 Gy), ovarian function (median age at last assessment 15.2 years) was normal in all but one in whom pubertal failure occurred. In only one patient, who developed pubertal failure after whole abdominal XRT and required sex steroid replacement therapy (HRT) to achieve normal secondary sexual characteristics, has there been evidence of reversibility of ovarian function with a documented conception at the age of 22.7 years. Five patients who developed pubertal failure required bilateral augmentation mammoplasties despite sex steroid replacement therapy. Four patients have had documented conceptions, all received whole abdominal XRT (20-26.5 Gy) and subsequently developed a premature menopause. There have been no live births, with all miscarriages occurring in the second trimester. The outlook for normal ovarian function following whole abdominal XRT is poor, flank XRT introduced intermittently from 1972, has resulted in less pubertal failure but the possibility of a premature menopause may with time become a reality.

Improved growth response to GH treatment in irradiated children

The growth response to two years of GH treatment was studied in fifteen children after radiotherapy for a cranial tumor. The growth response was compared to that of short children (-2 SD) and that of children with idiopathic growth hormone deficiency (GHD) of similar ages. All children were treated with hGH 0.1 IU/kg/day s.c.; which is a higher dose and frequency than previously reported for irradiated children. On this protocol the growth rate increased 5.0 +/- 0.5 cm/y (mean +/- SEM) the first year and 3.8 +/- 0.7 cm/y the second year compared to the growth rate the year before GH-treatment. Although the net gain in growth was higher than previously reported, the first year growth response was significantly reduced (p less than 0.05) compared to that of GHD-children (7.6 +/- 0.5 cm/y) but exceeded (p less than 0.05) that of short children (3.4 +/- 0.3 cm/y). The median spontaneous 24 h-GH secretion was 209 mU/l in the short children, 52 mU/l in the irradiated children and 16 mU/l in the idiopathic GHD children. Thus the growth increment varied inversely to the spontaneous GH secretion observed in the three groups.

Thyroid dysfunction after radiotherapy and chemotherapy of brain tumours

We investigated thyroid function in 119 survivors of treatment for brain tumours not involving the hypothalamo-pituitary region. Cranial irradiation did not effect thyroid function but 11 of 47 children (23%) who had spinal irradiation had raised concentrations of thyroid stimulating hormone. Chemotherapy further increased the incidence of thyroid dysfunction: two of four patients who had cranial irradiation and chemotherapy and 20 of 29 patients (69%) who had spinal irradiation and chemotherapy had increased thyroid stimulating hormone concentrations. Only six patients with raised thyroid stimulating hormone concentrations had low serum thyroxine concentrations. Four children had secondary hypothyroidism. Thyroid function should be monitored in children who have received chemotherapy or radiotherapy. A rise in thyroid stimulating hormone concentrations is the most sensitive indicator of thyroid dysfunction. Children with raised thyroid stimulating hormone concentrations should be treated with thyroxine.

Thyroid dysfunction in Hodgkin's disease

Radiotherapy to the neck and/or polychemotherapy late effects on the thyroid were investigated in 51 patients (34 males and 17 females) with Hodgkin's disease. Except for two untreated, recently diagnosed patients, all were studied after 1 to 105 months (median, 27.5 months) of completion of polychemotherapy. Age ranged from 6.2 to 36.6 years (median, 13.6 years). Patients were divided according to treatment into four groups: (A) patients treated with CVPP (cyclophosphamide, vinblastine, procarbazine, and prednisone); (B) 22 patients treated with CVPP plus radiotherapy (median radiation dose to the thyroid, 3000 cGy); (C) seven patients with ACOP/BVP (adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin, vinblastine, procarbazine); and (D) seven patients treated with different polychemotherapy protocols, four of whom also received radiotherapy. Elevated basal and/or post-TRH, -TSH levels were found in the following: Group A: two of 12 patients (17%); Group B: 11 of 22 (50%); Group C: four of seven (57%); and Group D: two of seven (28%). Positive antimicrosomal thyroid antibody titers (AM Ab) were found in the following: Group A: three of 12 patients (25%); Group B: six of 21 (28%), Group C: two of seven (28%); and Group D: one of six (17%). Of 46 patients studied, 12 (26%) had positive AM Ab; 37 of 46 patients were younger than 20 years of age, 11 (30%) of whom had positive AM Ab versus 4% in the normal population (P less than 0.001). Two recently diagnosed, untreated patients had either high TSH response to TRH or positive AM Ab. In conclusion, higher frequency of thyroid dysfunction was observed in patients receiving radiotherapy (50% versus 27%). Prevalence of positive AM Ab, apparently unrelated to therapy, was higher in young patients than in the normal population. A predisposition to autoimmune thyroid disease seems to be present in these patients, but it is not possible to discern how lymphoma and thyroiditis are interrelated.

Reproductive effects of the anticancer drug cyclophosphamide in male rats at different ages

This study was undertaken to determine the effects of the anticancer and immunosuppressant drug cyclophosphamide (CP) on several endpoints of the male rat reproductive system at different ages; 10-day-old (experiment A), 45-day-old (experiment B), and adult (experiment C) Sprague-Dawley rats were injected intraperitoneally with CP at doses of 20 mg/kg/day or/week and 100 mg/kg/week for 2 weeks (experiment A), doses of 20 mg/kg/day for 5 weeks and 100 mg/kg/day for 10 days (experiment B), and doses of 20 mg/kg/day for 5 weeks (experiment C). In all groups CP induced a significant rate of mortality. Body weight gain was moderately to severely reduced in two groups of experiment A (20 mg/kg/day and 100 mg/kg/week) and of experiment B (20 mg and 100 mg/kg/day) but normal in the others. Absolute as well as relative reproductive organ weights decreased following some of the treatments in experiments A and B. At the light microscope level, effects of CP ranged from nonapparent in immature rats (experiment A, 100 mg/kg/week for 2 weeks) and young adult animals (experiment B, 100 mg/kg/day for 10 days) to moderate in the other groups treated for 5 weeks (experiments B and C). Affected tubules exhibited atrophy, exfoliation, and a decrease in the number of spermatogonia, primary spermatocytes, and round and elongated spermatids. Sertoli cell function appeared preserved, whereas Leydig cells, present in the intratubular tissue of the rats in all the experiments, were occasionally and moderately altered in animals of experiment B, as shown by significant decreases of serum testosterone and LH levels. Leydig cell dysfunction in these rats was associated with normal in vitro basal and hCG-stimulated testosterone production. A significant decrease in epididymal sperm reserves was observed only in one group of animals (experiment B, 100 mg/kg/day for 10 days). Since in these animals the number of spermatids in the seminiferous tubules was normal, it is possible that CP at a high dose alters the epididymal function. Furthermore, fertility trials demonstrated that despite no change in the number of implantation sites, there was a dramatic fall in the number of fetuses per female in all the experimental groups. In conclusion, this study shows that in pre- and postpubertal rats treated chronically or subacutely, CP primarily and essentially induces alterations of germ cells, whereas this compound has little or no direct effect upon Leydig cell and Sertoli cell functions, respectively.

Temporal lobe and hypothalamic-pituitary dysfunctions after radiotherapy for nasopharyngeal carcinoma: a distinct clinical syndrome

Eleven patients with combined neurological and endocrine complications after external radiotherapy for nasopharyngeal carcinoma are described. Neurologically, memory disturbance, complex partial seizures and hypodense areas in one or both temporal lobes on CT were typical features. Endocrinologically, hypopituitarism was the prominent manifestation. This constellation of clinical features in a patient with previous radiotherapy to the nasopharynx characterises radiation injury to the inferomedial aspects of the temporal lobes and the hypothalamic-pituitary axis. While the parenchymal brain lesions may mimic metastases or glioma on CT, the associated endocrine disturbance would betray the correct diagnosis. The importance of recognising the hypopituitarism which may be clinically asymptomatic and which is amenable to therapy is emphasised, as is the need for a proper fractionation of the radiation dose to minimise the incidence of these disabling complications.

Endocrine function following high dose proton therapy for tumors of the upper clivus

The endocrine status of patients receiving proton radiation for tumors of the upper clivus was reviewed to evaluate the effect of high dose treatment on the pituitary gland. The fourteen patients had chordomas or low grade chondrosarcomas and were all treated by the same techniques. The median tumor dose was 69.7 Cobalt Gray Equivalent (CGE) with a range from 66.6 to 74.4 CGE. (CGE is used because modulated protons have an RBE of 1.1 compared to 60Co). The daily fraction size was 1.8-2.1 CGE. The median follow-up time is 48 months, ranging from 30 to 68 months. All treatments were planned using a computerized multi-dimensional system with the position of the pituitary outlined on the planning CT scan. Review of the dose distribution indicated that the dose to the pituitary ranged from 60.5 to 72.3 CGE, with a median of 67.6 CGE. One female patient had decreased thyroid and gonadotropin function at the time of diagnosis and has been on hormone replacement since that time. The other three females were all pre-menopausal at the time of radiotherapy. At this time four patients (3 males and 1 female) have developed endocrine abnormalities 14 to 45 months after irradiation. All four had evidence of hypothyroidism and two have also developed corticotropin deficiency. The three males had decreased testosterone levels; the female patient developed amenorrhea and hyperprolactinemia. All four are asymptomatic with ongoing hormone replacement.

Gonadal dysfunction after treatment of intracranial tumours

Ninety three children (51 boys, 42 girls) who had been treated for brain tumours not affecting the hypothalamopituitary axis, were studied for evidence of gonadal dysfunction. All had received cranial irradiation, 59 spinal irradiation, and 28 adjuvant chemotherapy. Mean age at treatment was 6.3 years (range 1.5-15). Mean follow up after completion of radiotherapy was 8.5 years (range 1-27). Primary ovarian damage occurred in seven out of 11 (64%) girls treated with craniospinal irradiation alone and in nine out of 14 (64%) of those treated with craniospinal irradiation and chemotherapy. The association with spinal irradiation was significant. Primary gonadal damage also occurred in three out of four children treated with chemotherapy combined with cranial irradiation and in three out of nine boys treated with chemotherapy and craniospinal irradiation but in no boy given craniospinal irradiation alone. The only common chemotherapeutic agent was a nitrosourea. Hypogonadotrophic hypogonadism was found in seven boys, 5.8% of children of pubertal age.

Prepubertal endocrine follow-up in subjects with Wilms' tumor

Twenty-three prepubertal subjects treated for Wilms' tumor (10 males and 13 females) were endocrinologically evaluated off therapy from 0.5 to 4.08 years. They were divided into two groups: 11 subjects (6M, 5F) who had received chemotherapy only (group 1) and 12 (4M, 8F) who had in addition received abdominal radiation (1,500-3,000 rads) (group 2). Follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid-stimulating hormone (TSH), free thyroxine (FT4), free tri-iodo thyronine (FT3), testosterone (T), estradiol-17 beta (E2), and cortisol (F) were measured by radioimmunoassay (RIA). Plasma levels of TSH, PRL, FT4, FT3, and F were normal in both groups, as were FSH, LH, T, and E2 in group 1. In group 2, female subjects showed FSH levels significantly higher than controls, while LH and E2 were normal; male subjects showed significantly higher LH levels, while FSH and T levels were normal. These results indicate that in the treatment protocol used by us for Wilms' tumor (WT), chemotherapy does not affect endocrine function, whereas abdominal radiation seems to damage gonadal function directly. The present findings indicate that gonadal damage may be revealed in WT before puberty not only in females, as has been previously reported, but also in male subjects.

Thyroid function in children after cytostatic treatment for acute leukemia

Sixty-one children were examined for thyroid dysfunction as an adverse late effect after cessation of antileukemic treatment. The aim of the study was to contribute to clarifying which types of therapy can cause this endocrine disorder. Our treatment protocols do not include cranial irradiation as CNS prophylaxis, but we give relatively intensive intrathecal methotrexate treatment. The results indicate that this cytostatic regimen alone does not cause thyroid dysfunction as an adverse late effect.

The effect of total body irradiation and bone marrow transplantation during childhood and adolescence on growth and endocrine function

Seventeen children (11 M, 6 F) with acute leukaemia and myeloproliferative disorders were investigated for growth and endocrine dysfunction. All had undergone bone marrow transplantation prepared with cyclophosphamide and single fraction total body irradiation (900-1000 cGy) between 1.5 and 3.8 (mean 2.2) years previously. The majority of children exhibited growth failure, which was of multiple aetiology. Ten patients, of whom eight had had previous prophylactic cranial irradiation, had evidence of growth hormone deficiency based on the reduced growth hormone response to insulin induced hypoglycaemia. Three patients had evidence of hypothalamic damage as shown by their growth hormone response to 200 micrograms GHRH (1-29) NH2 intravenously. Gonadal failure was common, assessed clinically, and biochemically by basal gonadotrophin and sex steroid concentrations. All four girls of adolescent age (10.6-14.1 years) had ovarian failure requiring sex steroid replacement. Of the eight boys of adolescent age (12.3-18.3 years), two had testicular failure requiring sex steroid supplements. Both of these had had previous testicular irradiation. Five others had compensated gonadal failure, and one had normal Leydig cell function. Abnormalities of the TSH response to TRH occurred in 10 patients but only three had overt hypothyroidism. Unlike growth hormone deficiency, gonadal and thyroid dysfunction showed no correlation with previous cranial radiotherapy.

A longitudinal study on growth and spontaneous growth hormone (GH) secretion in children with irradiated brain tumors

Longitudinal growth was studied in 27 children after radiotherapy for a brain tumor. Growth deviation (greater than or equal to 1 SD) was found in 56% of the children after 2 years and was most profound in prepubertal children aged between 3 and 8 years at the time of irradiation. In this group growth velocity was markedly reduced and no catch up was seen. In all children studied growth hormone (GH) secretion, measured as the spontaneous secretion over 24 hours, was found to be severely disturbed. Our conclusion is that all children with a growth deviation greater than or equal to 1 SD after radiotherapy (greater than or equal to 40 Gy) to the hypothalamo-hypophyseal region should be considered GH deficient. In such children GH treatment can be initiated without further testing.

Symptomatic hypothalamic-pituitary dysfunction in nasopharyngeal carcinoma patients following radiation therapy: a retrospective study

Endocrine assessment was performed in 32 relapse-free southern Chinese patients (21 males and 11 females, aged 27-50 years at the time of assessment) 5-17 years following radiation therapy (RT) alone for early nasopharyngeal carcinoma (NPC). Initial screening was done using questionnaires emphasizing on impaired sexual function and menstrual disturbance plus measurement of serum levels of thyroxine, free thyroxine index, thyrotropic hormone, prolactin, and additionally testosterone for males only. Those showing abnormalities were subjected to detailed pituitary function tests. Hypothalamic-pituitary dysfunction was found in 7 female patients and only 1 male patient. A delayed TSH response to thyrotropin releasing hormone suggesting a hypothalamic disorder was seen in 6 of the affected female patients, and hyperprolactinaemia in also 6. None of the patients had evidence of diabetes insipidus. Hypopituitarism became symptomatic 2-5 years after RT with a mean latent interval of 3.8 years. A practical protocol for regular endocrine assessment for NPC patients after RT has been proposed. Multiple linear regression analysis of the radiotherapeutic data from the 11 female patients indicates that the likelihood of late occurrence of symptomatic hypothalamic-pituitary dysfunction following RT is dependent on the TDF of the target dose to the nasopharyngeal region and the height of the upper margin of the opposed lateral facial fields above the diaphragma sellae (coefficient of multiple correlation = 0.9025). Except when the sphenoid sinus or the middle cranial fossa is involved, it is advisable to set the height of the upper margin of the lateral facial field at a level no higher than the diaphragma sellae. The hypothalamus and possibly the pituitary stalk as well may sustain permanent damage by doses of radiation within the conventional radiotherapeutic range for carcinomas.

Long-term endocrine sequelae after surgery, radiotherapy, and chemotherapy in children with medulloblastoma

Thirteen children with medulloblastoma, were studied after 2 to 62 months off radiotherapy and chemotherapy with methotrexate and BCNU. Ages at time of study ranged from 2.3 to 15.7 years. Eleven patients, followed for a mean of 22 months, showed a significant decrease of height score, whereas nine patients had deficient growth hormone (GH) response to provocative tests. Clinical pubertal progression was normal in all patients, and three of five girls with advanced pubertal development had menarche. No evidences of gonadotropin disturbances were found in five patients whereas seven had raised basal follicle-stimulating hormone (FSH) level or FSH response to luteinizing hormone-releasing hormone (LH-RH). Abnormalities in thyrotrophin (TSH) secretion were found in 9 of 13 patients. This study shows that poor growth and GH deficiency were frequent in our patients. The high frequency of thyroid disturbances observed point out the need of evaluating thyroid function for adequate replacement therapy. Perhaps modification of adjuvant chemotherapy in the future can diminish drug-induced gonadal damage.

Growth hormone neurosecretory dysfunction

The basis for understanding clinical disorders in the neuroregulation of GH secretion is derived from the complexity of the CNS-hypothalamic-pituitary axis. Studies in animals and humans demonstrate an anatomic, physiological and pharmacological evidence for neurosecretory control over GH secretion including neurohormones (GRH, somatostatin), neurotransmitters (dopaminergic, adrenergic, cholinergic, serotonergic, histaminergic, GABAergic), and neuropeptides (gut hormones, opioids, CRH, TRH, etc). The observation of a defect in the neuroregulatory control of GH secretion in CNS-irradiated humans and animals led to the hypothesis of a disorder in neurosecretion, GHND, as a cause for short stature. We speculate that in this heterogeneous group of children a disruption in the neurotransmitter-neurohormonal functional pathway could modify secretion ultimately expressed as poor growth velocity and short stature.

Hypothalamic hypopituitarism following cranial irradiation for nasopharyngeal carcinoma

Eight patients, one male and seven females, with no pre-existing hypothalamic-pituitary disease, who developed symptoms of hypopituitarism following cranial irradiation for nasopharyngeal carcinoma were studied 5 years or more after radiotherapy. All were GH deficient. Four of the patients with no GH response during insulin tolerance tests (ITT) showed increased GH in response to synthetic human growth hormone releasing factor (GRF-44). Four patients had impaired cortisol responses to ITT, and gradual but diminished cortisol responses to ovine corticotrophin releasing factor (CRF-41). There was no significant difference between mean peak increments in response to ITT and those in response to CRF-41. TSH responses to TRH were delayed in five and absent in two patients; four of these had low free T4 index. Prolactin was raised in all seven women and increased further in response to TRH. Two patients had impaired gonadotrophin responses to LHRH. None of the patients had clinical or biochemical evidence of diabetes insipidus. These data suggest that post-irradiation hypopituitarism in these patients results from radiation damage to the hypothalamus leading to varying degrees of deficiency of the hypothalamic releasing or inhibitory factors.

Thyroid function after postoperative radiation therapy in patients with breast cancer

Thyroid stimulating hormone (S-TSH) and thyroxine (S-T4) were measured in sera from 80 patients with breast cancer using radioimmunoassay. The patients had been irradiated after mastectomy 7.2 +/- 1.0 years earlier with 45 Gy in 3 to 4 weeks to parasternal, ipsilateral supraclavicular and axillary areas. Five patients (6%) had hypothyroidism with low S-T4 and elevated S-TSH levels. In addition, 12 patients (15%) had elevated (greater than 5 mU/l) S-TSH levels and normal S-T4 values. Shielding of the thyroid during irradiation and long-term follow-up of thyroid function with repeated hormone assays are recommended.

Which children should have growth hormone therapy?

Existing criteria for the diagnosis of growth hormone (GH) deficiency do not identify all children who can be made to grow faster with GH. There is a spectrum of GH secretion in short slowly growing normal children and in some cases the secretion may be inadequate to promote optimum growth in height. A diagnostic/therapeutic trial of GH therapy, with auxological monitoring, may be the only means of identifying some patients who will benefit. Assessment of the place for GH therapy in the treatment of short stature requires special knowledge of childhood diseases, growth, and endocrinology.

The effects of cranial irradiation on growth hormone secretion

Growth hormone (GH) secretion has been studied under physiological conditions and in response to standard pharmacological stimuli in 14 children, who had previously received cranial irradiation between two and fourteen years earlier. All fourteen showed a blunted GH response to insulin hypoglycaemia and, in twelve, the GH response to arginine stimulation was also subnormal. Physiological GH secretion was studied by measuring integrated GH concentrations in 30 min blood samples collected over a 24 hour period by a continuous withdrawal pump. Compared to normal controls (n = 5), the irradiated patients showed a significant reduction in the mean integrated GH concentration (2.2: 8.8 mU/l; p less than 0.002), the total 24 hour GH output (mean 105.7 mU vs. 391.7 mU; p less than 0.002) and the mean GH output during the first six hours of sleep (mean 48.2 mU vs. 226 mU; p less than 0.002). There was no significant correlation between the maximum peak GH response to either pharmacological test and the total 24 hour GH output. Conventionally most short children undergo two provocative tests of GH release and if the GH response to one of the two tests is normal, it is usually assumed that GH production is adequate. Adopting these criteria in this study it would have been assumed incorrectly that GH production was normal in two children. Nonetheless all 14 children showed a blunted GH response to an ITT as well as a reduced total 24 hour GH output.(ABSTRACT TRUNCATED AT 250 WORDS)

Initiation of spermatogenesis during chemotherapy for leukemia

Although the information is sparse, cytotoxic drugs have been suspected to cause serious damage to the immature testis, especially when the treatment is given during puberty. In a prospective, longitudinal study, we have investigated the effect of combination chemotherapy on the maturation of the germinative epithelium in 22 testicular biopsy specimens from 10 pubertal boys with acute lymphoblastic leukemia. Five of the boys developed complete spermatogenesis including spermatozoa during the treatment, the biopsy specimens of two patients showed partial maturation of the seminiferous epithelium, while the germ cells of two boys remained immature. In one patient, who received large doses of cyclophosphamide and cytosine arabinoside, all germ cells disappeared during the therapy. We conclude that a significant proportion of boys with acute lymphoblastic leukemia may develop potential fertility even while on treatment with cytotoxic drugs during puberty.

Leydig cell damage after testicular irradiation for lymphoblastic leukaemia

The effect of testicular irradiation on Leydig cell function has been studied in a group of boys irradiated between 1 and 5 years earlier for a testicular relapse of acute lymphoblastic leukaemia. Six of the seven boys irradiated during prepubertal life had an absent testosterone response to HCG stimulation. Two of the four boys irradiated during puberty had an appropriate basal testosterone level, but the testosterone response to HCG stimulation was subnormal in three of the four. Abnormalities in gonadotrophin secretion consistent with testicular damage were noted in nine of the 11 boys. Evidence of severe Leydig cell damage was present irrespective of whether the boys were studied within 1 year or between 3 and 5 years after irradiation, suggesting that recovery is unlikely. Androgen replacement therapy has been started in four boys and will be required by the majority of the remainder to undergo normal pubertal development.