Cyclical combination chemotherapy and thyroid function in patients with advanced Hodgkin's disease

Thyroid dysfunction during treatment with systemic antineoplastic therapy for childhood cancer: A systematic review

Thyroid dysfunction is known to occur following radiotherapy or chemotherapy for childhood cancer. Thyroid dysfunction during treatment for childhood cancer has, however, not been studied extensively, although thyroid hormones are of utmost importance during childhood. This information is needed to develop adequate screening protocols and may be of special importance with upcoming drugs, such as checkpoint inhibitors, which are highly associated with thyroid dysfunction in adults. In this systematic review we have evaluated the occurrence and risk factors for thyroid dysfunction in children during treatment with systemic antineoplastic drugs, up to three months after the end of therapy. Two review authors independently performed the study selection, data extraction and risk of bias assessment of included studies. After an extensive search (January 2021), in total six heterogeneous articles were included, reporting on 91 childhood cancer patients with a thyroid function test during treatment with systemic antineoplastic therapy for childhood cancer. All studies had risk of bias issues. Primary hypothyroidism was found in 18% of children treated with high dose interferon-α (HDI-α) and in 0-10% after tyrosine kinase inhibitors (TKIs). Transient euthyroid sick syndrome (ESS) was common (in 42-100%) during treatment with systematic multi-agent chemotherapy. Only one study addressed possible risk factors, showing different types of treatment to increase the risk. However, the exact prevalence, risk factors and clinical consequences of thyroid dysfunction remain unclear. Prospective high-quality studies including large study samples are needed to longitudinally assess the prevalence, risk factors and possible consequences of thyroid dysfunction during childhood cancer treatment.

The Continuum of Thyroid Disorders Related to Immune Checkpoint Inhibitors: Still Many Pending Queries

BACKGROUND

Until more data are available to shed light on the thyroid disorders related to immune checkpoint inhibitors (ICPi) implemented for the treatment of hematological malignancies, the decision-making is guided by pertinent data derived mostly from solid tumors.

METHODS

The present review provides a comprehensive and updated overview of the thyroid disorders related to ICPi, namely to inhibitors of cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death (PD) 1 (PD-1), and the ligand of the latter (PD-L1).

RESULTS

With the increasing recognition of ir thyroid disorders, many outstanding issues have emerged. Ir thyroid disorders are reminiscent of, but not identical to, thyroid autoimmunity. Interclass and intraclass ICPi differences regarding thyroid immunotoxicity await interpretation. The available data concerning the predictive value of thyroid autoantibodies for the development of ir thyroid disorders are inconclusive. Mounting data indicate an association of ir thyroid disorders with ICPi efficacy, but a causative link is still lacking. The path forward is a tailored approach, entailing: (i) the validation of tumor-specific, patient-specific, and ICPi-specific predictive factors; (ii) appropriate patient selection; (iii) the uncoupling of antitumor immunity from immunotoxicity; (iv) a multidisciplinary initiative; and (v) global registry strategies.

CONCLUSIONS

Untangling and harnessing the interrelationship of immuno-oncology with endocrinology underlying the ir thyroid disorders will yield the optimal patient care.

Alteration of Thyroid Function in Indian HER 2-Negative Breast Cancer Patients Undergoing Chemotherapy

BACKGROUND

Thyroid hormones (TH) are regulated by the hypothalamic-pituitary axis, which plays an important role in cell growth, differentiation, development and other aspects of metabolism. It is believed that an active hypothalamic-pituitary axis increases the susceptibility of thyroid dysfunction during systemic chemotherapy. In order to investigate the relation between thyroid function and chemotherapy the present study was designed to investigate TH in breast cancer patients receiving at least three cycles of chemotherapy. The levels of TH were measured at the baseline and before each cycle of chemotherapy.

MATERIALS AND METHODS

Blood samples for estimation of TH levels were collected from 80 (pre-menopausal-40; post-menopausal-40) breast cancer patients just before they were undergoing--1st, 2nd, 3rd and 4th cycle of chemotherapy. The serum was separated and T3, T4 and TSH levels were determined by chemiluminescence method.

RESULTS

T3 and T4 were found significantly decreased and TSH was found significantly increased after 1st (p<0.001), 2nd (p<0.0001) and 3rd cycle of chemotherapy (p<0.0001). The variation of T3 levels (decreased) and TSH levels (increased) was found more in post-menopausal (p<0.0001) women then in pre-menopausal women after 3rd cycle of chemotherapy as compared to baseline (p<0.001).

CONCLUSIONS

TH were remarkably altered after each cycle of chemotherapy leading to decline in thyroid function of breast cancer patients. Further, the results also indicated that post- menopausal women were more prone towards decline in thyroid function then pre-menopausal women. The present study proposes the monitoring of TH after each cycle of chemotherapy in breast cancer patients.

Thyroid dysfunction as an unintended side effect of anticancer drugs

BACKGROUND

Several of the currently used anticancer drugs may variably affect thyroid function, with impairment ranging from modified total but not free concentration of thyroid hormones to overt thyroid disease.

SUMMARY

Cytotoxic agents seem to alter thyroid function in a relatively small proportion of adult patients. Anticancer hormone drugs may mainly alter serum levels of thyroid hormone-binding proteins without clinically relevant thyroid dysfunction. Old immunomodulating drugs, such as interferon-α and interleukin-2, are known to induce variably high incidence of autoimmune thyroid dysfunction. Newer immune checkpoint inhibitors, such as anti-CTLA4 monoclonal antibodies, are responsible for a relatively low incidence of thyroiditis and may induce secondary hypothyroidism resulting from hypophysitis. Central hypothyroidism is a well-recognized side effect of bexarotene. Despite their inherent selectivity, tyrosine kinase inhibitors may cause high rates of thyroid dysfunction. Notably, thyroid toxicity seems to be restricted to tyrosine kinase inhibitors targeting key kinase-receptors in angiogenic pathways, but not other kinase-receptors (e.g., epidermal growth factor receptors family or c-KIT). In addition, a number of these agents may also increase the levothyroxine requirement in thyroidectomized patients.

CONCLUSIONS

The pathophysiology of thyroid toxicity induced by many anticancer agents is not fully clarified and for others it remains speculative. Thyroid dysfunction induced by anticancer agents is generally manageable and dose reduction or discontinuation of these agents is not required. The prognostic relevance of thyroid autoimmunity, overt and subclinical hypothyroidism induced by anticancer drugs, the value of thyroid hormone replacement in individuals with abnormal thyrotropin following anticancer systemic therapy, and the correct timing of replacement therapy in cancer patients need to be defined more accurately in well-powered prospective clinical trials.

Thyroid dysfunction from antineoplastic agents

Unlike cytotoxic agents that indiscriminately affect rapidly dividing cells, newer antineoplastic agents such as targeted therapies and immunotherapies are associated with thyroid dysfunction. These include tyrosine kinase inhibitors, bexarotene, radioiodine-based cancer therapies, denileukin diftitox, alemtuzumab, interferon-α, interleukin-2, ipilimumab, tremelimumab, thalidomide, and lenalidomide. Primary hypothyroidism is the most common side effect, although thyrotoxicosis and effects on thyroid-stimulating hormone secretion and thyroid hormone metabolism have also been described. Most agents cause thyroid dysfunction in 20%-50% of patients, although some have even higher rates. Despite this, physicians may overlook drug-induced thyroid dysfunction because of the complexity of the clinical picture in the cancer patient. Symptoms of hypothyroidism, such as fatigue, weakness, depression, memory loss, cold intolerance, and cardiovascular effects, may be incorrectly attributed to the primary disease or to the antineoplastic agent. Underdiagnosis of thyroid dysfunction can have important consequences for cancer patient management. At a minimum, the symptoms will adversely affect the patient's quality of life. Alternatively, such symptoms can lead to dose reductions of potentially life-saving therapies. Hypothyroidism can also alter the kinetics and clearance of medications, which may lead to undesirable side effects. Thyrotoxicosis can be mistaken for sepsis or a nonendocrinologic drug side effect. In some patients, thyroid disease may indicate a higher likelihood of tumor response to the agent. Both hypothyroidism and thyrotoxicosis are easily diagnosed with inexpensive and specific tests. In many patients, particularly those with hypothyroidism, the treatment is straightforward. We therefore recommend routine testing for thyroid abnormalities in patients receiving these antineoplastic agents.

TSH suppression as a possible means of protection against hypothyroidism after irradiation for childhood Hodgkins lymphoma

Hypothyroidism remains a common late effect after irradiation of the neck/mediastinum for Hodgkins lymphoma (HL). We evaluated the protective effect of TSH suppression during neck/mediastinum irradiation. From 1998 to 2001, 14 consecutive euthyroid children were given, before and until the end of their radiotherapy on neck/mediastinum, L-thyroxine at TSH-suppressive doses. The 14 patients had adequate TSH suppression during irradiation in 8, inadequate in 6. The 8-year hypothyroidism-free-survival after irradiation was 75 ± 15% for the former group, 0% for the latter (P = 0.009). TSH suppression could have a protective effect on thyroid function as shown in a small group of patients with HL.

Thyroid function and thyroid autoimmunity in childhood acute lymphoblastic leukemia off-therapy patients treated only with chemotherapy

OBJECTIVE

Scanty data are available about the thyroid function in childhood acute lymphoblastic leukemia (ALL) off-therapy patients treated only with chemotherapy. We aimed to assess the prevalence of thyroid autoimmunity and thyroid dysfunction in such patients.

DESIGN

Case-control cross-sectional study.

METHODS

Eighty-four patients diagnosed with ALL and treated only with chemotherapy. Mean age at diagnosis 5.9+/-3.6 yr, at recruitment 12.1+/-4.3 yr. The treatment had been stopped 4.3+/-3.2 yr before recruitment. A control group of 60 subjects was recruited. Free T4, TSH, anti-thyroperoxidase, and anti-thyroglobulin antibodies were measured.

RESULTS

Anti-thyroglobulin and anti-thyroperoxidase antibodies were negative in all patients. TSH was increased in 7 patients (8.3%) and 3 controls (5.0%). Free T4 was within the normal limits in all patients and controls.Mean TSH and free T4 levels did not statistically differ between controls and ALL offtherapy patients. TSH was negatively correlated with the age at the diagnosis (p=0.01) and the age at the end of therapy (p=0.008). Anti-thyroglobulin and/or anti-thyroperoxidase antibodies were detected in 3 controls (5%; vs study group: p=0.038), 1 of them with increased TSH.

CONCLUSIONS

Some patients present hyperthyrotropinemia, without anti-thyroid antibodies, with a prevalence comparable to the control group. The thyroid gland seems more prone to be damaged by chemotherapy at a younger age. We think that a thyroid follow- up in ALL off-therapy patients may be advisable and should be differentiated on the basis of the age at the end of treatment, with more frequent tests for younger patients.

Hypothyroidism related to tyrosine kinase inhibitors: an emerging toxic effect of targeted therapy

Despite their inherent selectivity, targeted therapies such as tyrosine kinase inhibitors (TKIs) can cause unusual adverse effects. Sunitinib and sorafenib are multitargeted TKIs that have been demonstrated to induce hypothyroidism and thyroid dysfunction. Retrospective studies indicate that sunitinib can induce hypothyroidism in 53-85% of patients, and in prospective studies this complication has been reported in 36-71% of patients. Sorafenib has been reported to be responsible for hypothyroidism in 18% of patients with metastatic renal-cell carcinoma. Furthermore, imatinib and sunitinib seem to increase the requirement of levothyroxine in hypothyroid patients. The management of thyroid dysfunction and possible related symptoms, such as fatigue, represents a challenge to oncologists. We propose a diagnostic and therapeutic algorithm for the management of TKI-related hypothyroidism. Prospective trials are needed to define the incidence of overt and subclinical hypothyroidism and thyroid dysfunction during therapy with sunitinib, sorafenib and potentially other TKIs. The safety and efficacy, and optimal dosing and timing of starting replacement therapy in patients affected by TKI-related hypothyroidism need accurate appraisal and should be evaluated prospectively in appropriately designed trials.

The natural history of thyroid function abnormalities after treatment for childhood cancer

The aim of the study was to find out which of childhood cancer survivors are at higher risk of thyroid dysfunction, and the timeframe for its development. The consequences of different treatments, particularly chemotherapy, were of interest. Follow-up data for 291 patients from a cohort of 360 patients were available and analysed in this retrospective study. Impaired thyroid function occurred in 71/291 (24%) patients: brain tumours 30/65 (46%), Hodgkin's disease (HD) 10/21 (48%), leukaemia/non Hodgkin's lymphoma (NHL) 19/140 (14%) and others 12/65 (18%). Patients with brain tumours had a higher hazard ratio (HR) over leukaemia/NHL (HR 7.47) but not over HD (HR 1.57). These patients also developed thyroid hypofunction earlier than patients with HD or leukaemia/NHL. Age at diagnosis did not have an effect on the occurrence or timeframe of development of thyroid hypofunction. Radiotherapy (HR 4.68) and radiotherapy combined with chemotherapy (HR 2.90) were associated with a higher risk than chemotherapy alone. Chemotherapy added to radiotherapy tended to increase risk (HR 2.42 95% confidence interval (CI) 1.00-5.87). Craniospinal irradiation did not differ significantly from total body irradiation (TBI) (HR 1.09 95%CI 0.25-4.76) or direct thyroid irradiation (HR 0.81 95%CI 0.32-2.06), but cranial irradiation (CIR) (HR 0.18 95%CI 0.08-0.38) was less harmful to thyroid function. Girls were more prone to effects of irradiation (HR 2.10 95%CI 1.15-3.82). All treatments, excluding surgery, predispose to thyroid dysfunction. Suggestions for follow-up of thyroid function are made.

Thyroid function in paediatric and young adult patients after sarcoma therapy: a report from the Late Effects Surveillance System

OBJECTIVE

The role of chemotherapy in thyroid sequelae after cancer treatment has not been studied systematically, especially in sarcoma patients. The aim of this study was to determine the incidence of post-therapeutic thyroid disorders and their contributing factors in a cohort of paediatric sarcoma patients.

DESIGN

Late effects of sarcoma treatment have been collected prospectively within the Late Effects Surveillance System (LESS) in Germany, Austria and Switzerland since 1998.

PATIENTS

We studied 340 relapse-free paediatric patients (median age at diagnosis 12.2 [interquartile range (IQR) = 7.3-15.6 years] treated for osteosarcoma, soft tissue sarcoma or Ewing's sarcoma within the COSS-96, CWS-96/CWS-2002P or EICESS-92/EURO-E.W.I.N.G.-99 therapy trials. In addition to polychemotherapy, 127 patients were irradiated (mean cumulative dose 47 +/- 9.7 Gy), including 51 patients with irradiation to the head/neck region. Median follow-up was 24.6 (IQR = 11.9-44.9) months.

MEASUREMENTS

We reviewed the results of yearly examinations of serum TSH and fT4 levels and thyroid ultrasound examinations.

RESULTS

The incidence of thyroid disorders was 37% (19/51, 95% CI 24-52%) in patients with head/neck irradiation, and 11% (32/289, 95% CI 8-15%) in patients without irradiation to the head/neck. Thyroid disorders were more frequent in patients treated with idarubicin (P = 0.027) and trofosfamide (P = 0.016). We also found a significant association between raised TSH levels and treatment with trofosfamide (P = 0.008) or idarubicin (P = 0.037) (n = 250).

CONCLUSIONS

The incidence of thyroid disorders in the head/neck-irradiated group was high. Even without head/neck irradiation, we found an increased proportion of patients with thyroid disorders, possibly as a result of chemotherapy.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of the treatment of childhood cancers. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic agents and radiation therapy. This article reviews hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteopenia-osteoporosis and obesity.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of childhood cancers and their treatments. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic drugs and radiation therapy. This article will explore the current literature about endocrine late effects of hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteoporosis and obesity.

Growth following malignancy

Disturbed growth in the child surviving cancer is multifactorial. This chapter examines the evidence for, and the difficulties in determining, individual drug treatment or disease effects at multiple endocrine levels influencing growth and against a changing baseline of adjuvant cancer therapies with potentially additive toxicity. The evolutionary pattern and potential aetiology of the neuro-endocrine deficit and growth-plate disturbance, the (unrandomized) effects of hormone replacement therapy and areas which require further study are also addressed. The reasons why growth hormone (GH) secretion is so exquisitely sensitive to disturbance, even though deficiencies soon after lesser cranial insults can be difficult to detect, are explored with evidence cited from the few existing prospective and interventional studies. The extent and nature of the hypothalamo-pituitary disturbance needs further prospective interventional study and disease-site- and treatment-specific comparisons. Practical treatment and surveillance strategies to optimize growth potential, age-appropriate development, peak bone mineral accretion, hair re-growth and future health and well-being are also suggested. Health-related outcomes resulting from today's newer therapies and enhanced surveillance need documenting in future (inter)national cancer trials, where randomized studies of hormonal intervention may also become possible.

Hypothyroidism in children with medulloblastoma: a comparison of 3600 and 2340 cGy craniospinal radiotherapy

PURPOSE

To determine if low-dose craniospinal irradiation (2340 cGy) with chemotherapy is associated with a lower incidence of hypothyroidism compared to standard dose (3600 cGy) with or without chemotherapy in children with medulloblastoma.

PATIENTS AND METHODS

Between 1980 and 1999, 32 patients < or =20 years old survived after craniospinal irradiation with or without chemotherapy. Twenty patients received 3600 cGy craniospinal irradiation (CSI), whereas 12 had 2340 cGy CSI; all patients received a posterior fossa boost to a total dose 5040-5580 cGy. The median ages at the time of CSI for those receiving 2340 cGy and 3600 cGy were 7.2 and 10.2 years, respectively. Chemotherapy (CT) was employed in 22 children. All children who received 2340 cGy had CT consisting of vincristine, CCNU, and either cisplatin or cyclophosphamide. Ten of 20 (50%) patients receiving 3600 cGy had CT; the most common regimen was vincristine, CCNU, and prednisone. Serum-free thyroxine and thyroid-stimulating hormone concentrations were measured in all children at variable times after radiotherapy. Thyroid-stimulating hormone responses to i.v. thyrotrophin-releasing hormone were assessed in those suspected of having central hypothyroidism. Median follow-up for children receiving 2340 cGy was 5 years (range: 2-11.2 years), whereas for those receiving 3600 cGy, follow-up was 12.5 years (range: 2.4-20 years).

RESULTS

Eighteen patients (56%) developed hypothyroidism at a median time after radiotherapy of 41 months (range: 10 months to 18 years). Primary hypothyroidism was more common than central hypothyroidism (38% and 19%). All 7 children <5 years developed hypothyroidism, whereas 9 of 15 (60%) ages 5-10 and 2 of 10 (20%) age >10 years had hypothyroidism (p < 0.001). Hypothyroidism was documented in 10 of 12 (83%) who had 2340 cGy + CT, 6 of 10 (60%) who had 3600 cGy + CT, and 2 of 10 (20%) who had 3600 cGy without CT (p < 0.025).

CONCLUSIONS

Current treatment regimens consisting of chemotherapy and 2340 cGy craniospinal irradiation followed by a posterior fossa boost for medulloblastoma do not show a reduction of hypothyroidism. Young age and use of chemotherapy were associated with a higher incidence of hypothyroidism.

Thyroid dysfunction after mantle irradiation of Hodgkin's disease patients

Thyroid dysfunction can develop in patients with Hodgkin's disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, lymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated.

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.

Thyroid function after treatment of brain tumors in children

In 134 children who had been treated for a brain tumor not involving the hypothalamic-pituitary axis, thyroid function was assessed up to 24 years after treatment with cranial or craniospinal irradiation. In addition, 78 children received up to 2 years of cytotoxic chemotherapy. Of 85 children who received craniospinal irradiation, 30 (35%) had abnormalities of thyroid function, and 10 (20%) of 49 who received cranial irradiation had such abnormalities. Frank hypothyroidism developed in three children and thyrotoxicosis in one. Thirty-six children had an elevated thyroid-stimulating hormone level in the presence of a normal thyroxine level; in 16 of them the thyroid-stimulating hormone level subsequently returned to normal. Twenty-eight children who were treated between 1960 and 1970 were excluded from the analysis. Of 34 children who received cranial irradiation, five had thyroid dysfunction and 24 of 72 who received craniospinal irradiation had such dysfunction (p = 0.013). Thyroid dysfunction was present in 4 of 35 children who received no chemotherapy and in 25 of 71 who received chemotherapy (p = 0.014). Direct irradiation plus chemotherapy was more damaging than irradiation alone. These data confirm the high incidence of thyroid dysfunction when the thyroid gland is included in the radiation field. However, in a high proportion, the thyroid abnormalities are minor and revert to normal with time; life-long replacement therapy with thyroxine may be unnecessary.

Endocrine disorders following treatment of childhood brain tumours

We have studied the long-term endocrine effects of treatment on 144 children treated for brain tumours. All received cranial irradiation, 86 also received spinal irradiation and 34 chemotherapy. Almost all patients (140 of 144) had evidence of growth hormone insufficiency. Treatment with growth hormone was effective in maintaining normal growth but could not restore a deficit incurred by delay in instituting treatment. The effect of spinal irradiation on spinal growth was not corrected by growth hormone. As spinal growth makes the major contribution to the pubertal growth spurt and limb length the major contribution to childhood growth, treatment with GH will have maximal effect on leg length if instituted before the onset of puberty. Primary thyroid dysfunction was found in 11 of 47 children (23%) treated with craniospinal irradiation but in none treated with cranial irradiation alone. The incidence rose to 69% of 29 children treated with spinal irradiation and chemotherapy and to 50% of four children treated with cranial irradiation and chemotherapy. This effect of chemotherapy has not previously been reported and was detected by us through measurement of serum TSH concentration. Primary thyroid dysfunction requires treatment with thyroxine to prevent increasing the risk of secondary thyroid tumours. Seven of 20 girls (35%) treated with spinal irradiation had primary ovarian dysfunction as determined by raised gonadotrophin levels. Chemotherapy increased this, but not significantly. Three of 15 boys (20%) treated with chemotherapy had primary testicular dysfunction. Gonadotrophin deficiency occurred in seven boys. Four of 90 children had deficiency of cortisol secretion in response to hypoglycaemia. These results confirm the requirement for long-term follow-up of children treated for brain tumours from the endocrine point of view. Anticipation of hormone deficiencies and replacement treatment can improve the quality of life of survivors.

Thyroid function in survivors of cancer

Thyroid function was assessed in three selected groups of children who had survived cancer. Children in group 1 had received radiotherapy to the thyroid area, group 2 had radiotherapy to the thyroid area and adjuvant chemotherapy, and group 3 had chemotherapy with or without radiotherapy away from the thyroid area. There were 75 survivors and 63 (40 boys, 23 girls) were available for study. Eighteen (29%) were found to have thyroid dysfunction, and these included all those who had had lymphangiograms or received a radiation dose greater than 40 Gy to the thyroid area. Only nine of the 18 children were already known to have thyroid dysfunction, and only 15 of 44 children who had had irradiation to the thyroid area had had their thyroid function examined. This study shows that children who have received radiotherapy to the thyroid area should have their thyroid function assessed regularly. Chemotherapy does not appear to be a risk factor but longer follow up of these children is necessary.

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.

Hypothyroidism and Graves' disease after mantle irradiation: a follow up study

Fifty of 66 patients whose thyroid function had previously been assessed 7-139 months after irradiation for Hodgkin's disease were re-evaluated 35 +/- 3 months later. They could be divided into three groups: those whose thyroid function had been normal in the first study (N = 26), those who had had asymptomatic impaired thyroid reserve (N = 19), and those in whom evidence of Graves' disease had developed (N = 5). The 26 patients who had been euthyroid when first studied had developed significant increases in mean thyroid-stimulating hormone (TSH) levels (basal and following thyrotrophin releasing hormone) without changes in mean free thyroxine index (FTI). In three of these patients, each studied within six years of irradiation, basal TSH had risen to hypothyroid levels. There were no significant changes in mean FTI or basal and peak TSH in 19 patients who had demonstrated impaired thyroid reserve in the first study. The cumulative incidence of impaired thyroid reserve in the total cohort is now 30/66 (45%) but only one of these 30 has developed clinical hypothyroidism. Five patients developed evidence of Graves' disease. Two patients with thyrotoxicosis and one with euthyroid Graves' disease were found in the initial study. On re-evaluation, a third patient had developed frank thyrotoxicosis and another euthyroid Graves' disease, giving a cumulative incidence of Graves' disease of 5/66 (7%). Three of these five were HLA-DR3 and three had measurable thyrotrophin binding inhibiting immunoglobulins. We conclude that impaired thyroid reserve continues to develop within six years of mantle irradiation in adults but once established appears to remain stable.(ABSTRACT TRUNCATED AT 250 WORDS)

Late cardiac, thyroid, and pulmonary sequelae of mantle radiotherapy for Hodgkin's disease

Cardiac, thyroid and pulmonary function were evaluated in 25 patients aged 35 years or under, treated for Hodgkin's disease by mantle radiotherapy 5-16 years previously. No patient had symptoms of heart disease. Although thallium myocardial perfusion scintigraphy was normal in all patients, abnormalities of myocardial function were detected in 6 (24%) patients using gated equilibrium rest and exercise radionuclide ventriculography. Resting left ventricular ejection fraction (LVEF) was abnormal in 1 patient, and in 3 patients there was an abnormal LVEF response to exercise. All 6 patients had right ventricular dilatation. Apical hypokinesia was present in 4 of these patients. A small asymptomatic pericardial effusion was detected by M-Mode echocardiography in only 2 (8%) patients. Twenty-three (92%) patients had evidence of abnormal thyroid function. Two (8%) patients had become clinically hypothyroid. Serum TSH was elevated in 13 (52%) patients and TRH stimulation test was abnormal in a further 10 (40%) patients in whom TSH was normal. Pulmonary function studies showed a moderate decrease in diffusing capacity (72% of predicted) and a minor reduction in lung volume. Although a high incidence of cardiac, thyroid and pulmonary abnormalities was detected, only the 2 patients who had become hypothyroid were symptomatic. Modification of the irradiation technique may reduce the incidence of cardiac abnormalities, but is unlikely to alter significantly the thyroid or pulmonary sequelae.

Thyroid dysfunction after radiotherapy in children with Hodgkin's disease

Thyroid function was measured in 119 children, 16 years of age or less, after radiotherapy (XRT) for Hodgkin's disease. Thyroid abnormalities developed in 4 of 24 children (17%) who received 2600 rad or less, and in 74 of 95 children (78%) who received greater than 2600 rad to the cervical area, including the thyroid. The abnormality in all but three (one with hyperthyroidism and two with thyroid nodules) included the development of elevated levels of thyroid stimulating hormone (TSH). Age, sex, and administration of chemotherapy were not significant factors in the development of thyroid dysfunction. All children had lymphangiograms (LAG) and no time relationship was noted between thyroid dysfunction and LAG-XRT interval. The mean interval from radiotherapy to documented thyroid dysfunction was 18 months in the low-dose group and 31 months in the high-dose group, with most patients becoming abnormal within 3 to 5 years. Of interest was a spontaneous return of TSH to within normal limits in 20 children and substantial improvement in another 7. This study confirms the occurrence of dose-related occult hypothyroidism in children following external irradiation of the neck.