Serial thyroid function measurements in children with Hodgkin disease

Primary Hypothyroidism in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

From the Pediatric Normal Tissue Effects in the Clinic (PENTEC) initiative, a systematic review and meta-analysis of publications reporting on radiation dose-volume effects for risk of primary hypothyroidism after radiation therapy for pediatric malignancies was performed.

METHODS AND MATERIALS

All studies included childhood cancer survivors, diagnosed at age <21 years, whose radiation therapy fields exposed the thyroid gland and who were followed for primary hypothyroidism. Children who received pituitary-hypothalamic or total-body irradiation were excluded. PubMed and the Cochrane Library were searched for studies published from 1970 to 2017. Data on age at treatment, patient sex, radiation dose to neck or thyroid gland, specific endpoints for hypothyroidism that were used in the studies, and reported risks of hypothyroidism were collected. Radiation dose-volume effects were modeled using logistic dose response. Relative excess risk of hypothyroidism as a function of age at treatment and sex was assessed by meta-analysis of reported relative risks (RR) and odds ratios.

RESULTS

Fifteen publications (of 1709 identified) were included for systematic review. Eight studies reported data amenable for dose-response analysis. At mean thyroid doses of 10, 20, and 30 Gy, predicted rates of uncompensated (clinical) hypothyroidism were 4%, 7%, and 13%, respectively. Predicted rates of compensated (subclinical) hypothyroidism were 12%, 25%, and 44% after thyroid doses of 10, 20, and 30 Gy, respectively. Female sex (RR = 1.7, P < .0001) and age >15 years at radiation therapy (RR = 1.3, P = .005) were associated with higher risks of hypothyroidism. After a mean thyroid dose of 20 Gy, predicted risks of hypothyroidism were 13% for males <14 years of age, increasing to 29% for females >15 years of age.

CONCLUSION

A radiation dose response for risk of hypothyroidism is evident; a threshold radiation dose associated with no risk is not observed. Thyroid dose exposure should be minimized when feasible. Data on hypothyroidism after radiation therapy should be better reported to facilitate pooled analyses.

Classical Hodgkin lymphoma

Classical Hodgkin lymphoma is one of the more frequent lymphomas and is generally considered a highly curable disease with standard first-line chemotherapy and radiotherapy in some cases. Despite these outstanding results, major problems remain unresolved. First, there are still patients who will not be cured with front-line regimens and, second, many patients who are cured of classical Hodgkin lymphoma continue to die prematurely due to the late toxic effects of their therapy. Because the median age of patients with classical Hodgkin lymphoma is in the mid-30s, the disease's impact on the number of years lost from productive life is remarkable. In recent years, the gold standard of chemotherapy (often combined with radiotherapy) has changed, with the approval of immunotherapy mostly in relapse settings.

Assessment of Treatment-Related Thyroid Dysfunction in Patients with Head and Neck Cancer

Objective

To assess thyroid dysfunction in head and neck cancer patients who have received external beam radiotherapy according to radiotherapy fields and dose, tumor site and other local or systemic treatments retrospectively and prospectively and propose a follow-up schedule.

Material and methods

A total of 378 patients was classified into two groups. Group I (n = 345) consisted of surgically treated 153 laryngeal, 80 nasopharyngeal and 112 oral cavity/oropharyngeal carcinoma patients; these patients were evaluated retrospectively for treatment-related thyroid dysfunction using their data files. Group II included 33 patients with head and neck cancer who were evaluated prospectively. Thyroid function tests were performed at the beginning of the radiotherapy and every three months after the radiotherapy course, and thyroid dysfunction regarding surgery, radiotherapy and chemotherapy was evaluated.

Results

In Group I, the median follow-up for 153 operated laryngeal carcinoma patients was 44 months. Four (2.6%) of them were found to have clinically apparent hypothyroidism. After a median follow-up of 36 months, none of the 80 nasopharyngeal carcinoma patients showed signs of hypothyroidism. Clinically apparent hypothyroidism was detected in only 1 (0.8%) of the oral cavity/oropharyngeal carcinoma patients after a median follow-up of 25 months. In Group II, 1 (3%) patient was found to have thyroid dysfunction postoperatively prior to radiotherapy. At the time of analysis, 29 (87.8%) patients were euthyroidic, 2 (6.1%) patients had subclinical and 2 (6.1%) patients had clinical hypothyroidism. All patients with thyroid dysfunction have had combined surgery and radiotherapy, and none of the patients treated with radical radiotherapy has experienced hypothyroidism.

Conclusions

Even after a short follow-up, the incidence of thyroid dysfunction was 12.2% in head and neck cancer patients treated with combined surgery and radiotherapy. We recommend thyroid function tests in these patients prior to and once every 3–6 months after the radiotherapy course.

Thyroid abnormalities in survivors of childhood cancer

OBJECTIVE

To investigate the late side effects of childhood cancer therapy on the thyroid gland and to determine the risk factors for development of thyroid disorder among childhood cancer survivors.

METHODS

One hundred and twenty relapse-free survivors of childhood cancer (aged 6-30 years) were included in this study. The diagnoses of patients were lymphoma, leukemia, brain tumor, rhabdomyosarcoma and nasopharyngeal carcinoma (NPC). The patients were divided into two groups depending on the treatment: group 1-chemotherapy (ChT) only (n=52) and group 2-combination therapy of ChT + radiotherapy (RT) (head/neck/thorax) (n=68). Thyroid function tests, urinary iodine levels, and thyroid gland ultrasound examinations were evaluated in both groups.

RESULTS

Incidence of thyroid disease was 66% (n=79) in the survivors. The thyroid abnormalities were: hypothyroidism (HT) (n=32, 27%), thyroid nodules (n=27, 22%), thyroid parenchymal heterogeneity (n=40, 33%), autoimmune thyroiditis (n=36, 30%), and thyroid malignancy (n=3, 2%). While the incidence of HT and thyroid nodules in group 2 was significantly higher than in group 1, the incidence of thyroid parenchymal heterogeneity and autoimmune thyroiditis was similar in the two patient groups. HT and thyroid malignancy were seen only in group 2. In multivariate logistic regression analysis, a history of Hodgkin lymphoma (HL), brain tumor and NPC, as well as cervical irradiation and 5000-5999 cGy doses of radiation were found to constitute risk factors for HT. History of HL and 4000-5999 cGy doses of radiation were risk factors for thyroid nodules. Head/neck irradiation and treatment with platinum derivatives were risk factors for autoimmune thyroiditis. In univariate analysis, a history of NPC, cervical + nasopharyngeal irradiation, and treatment with platinum derivatives were risk factors for thyroid parenchymal heterogeneity.

CONCLUSION

Our results indicate that there is especially an increased risk of HT and thyroid nodules in patients treated with combination therapy of ChT with head/neck/thorax RT. Although chemotherapeutic agents per se do not seem to cause HT, longer follow-up is needed to assess whether or not there is an increased risk for autoimmune thyroiditis and thyroid parenchymal heterogeneity after antineoplastic therapy.

Long-term effects of radiation exposure among adult survivors of childhood cancer: results from the childhood cancer survivor study

In the last four decades, advances in therapies for primary cancers have improved overall survival for childhood cancer. Currently, almost 80% of children will survive beyond 5 years from diagnosis of their primary malignancy. These improved outcomes have resulted in a growing population of childhood cancer survivors. Radiation therapy, while an essential component of primary treatment for many childhood malignancies, has been associated with risk of long-term adverse outcomes. The Childhood Cancer Survivor Study (CCSS), a retrospective cohort of over 14,000 survivors of childhood cancer diagnosed between 1970 and 1986, has been an important resource to quantify associations between radiation therapy and risk of long-term adverse health and quality of life outcomes. Radiation therapy has been associated with increased risk for late mortality, development of second neoplasms, obesity, and pulmonary, cardiac and thyroid dysfunction as well as an increased overall risk for chronic health conditions. Importantly, the CCSS has provided more precise estimates for a number of dose-response relationships, including those for radiation therapy and development of subsequent malignant neoplasms of the central nervous system, thyroid and breast. Ongoing study of childhood cancer survivors is needed to establish long-term risks and to evaluate the impact of newer techniques such as conformal radiation therapy or proton-beam therapy.

White race as a risk factor for hypothyroidism after treatment for pediatric Hodgkin's lymphoma

PURPOSE

Hypothyroidism frequently occurs after treatment for pediatric Hodgkin's lymphoma, but race has not been investigated as a risk factor for this delayed toxicity. The aim of this study was to determine whether race is an independent risk factor for hypothyroidism in survivors of pediatric Hodgkin's lymphoma.

PATIENTS AND METHODS

To identify differences between black and white patients in the development of hypothyroidism after treatment for Hodgkin's lymphoma, we conducted a retrospective study of consecutively treated pediatric patients with newly diagnosed Hodgkin's lymphoma treated at St Jude Children's Research Hospital (Memphis, TN) from January 1980 through December 2002. Clinical or biochemical hypothyroidism was defined by an above normal thyroxine-stimulating hormone concentration or by the need for thyroid hormone replacement therapy.

RESULTS

The 461 patients (388 white patients, 73 black patients) where followed for a median of 11.3 years (range, 1.8 to 24.9 years). Hypothyroidism developed in 196 (43%) of 461 patients after a median of 2.9 years (range, 0.7 to 11.3 years) after diagnosis of Hodgkin's lymphoma. Hypothyroidism developed in 47% of white patients but in only 21% of black patients (hazard ratio = 2.7; 95% CI, 1.6 to 4.6). After adjusting for other risk factors for hypothyroidism (thyroid radiation dose, sex, and nodular sclerosis histology), the risk of hypothyroidism in white patients was 2.5 times (95% CI, 1.5 to 4.3 times) the risk in black patients (P < .001).

CONCLUSION

White patients have a higher risk of hypothyroidism after neck irradiation for pediatric Hodgkin's lymphoma than black patients.

Long-term follow-up of pediatric cancer survivors: education, surveillance, and screening

Cancer and its treatment predispose childhood cancer survivors to chronic or late occurring health problems that may not become clinically significant until many years after therapy. Frequently, long-term survivors of childhood cancer report late cancer-related effects that diminish quality of life and increase the risk of early mortality. Risk-based health care that involves a personalized plan for surveillance, screening, and prevention is recommended to reduce cancer-related morbidity in childhood cancer survivors. To implement optimal risk-based care, the survivor and health care provider must have accurate information about cancer diagnosis, treatment modalities, and potential cancer-related health risks to guide screening and risk-reducing interventions. However, previous studies evaluating health knowledge of childhood cancer survivors demonstrate noteworthy deficits and misperceptions about their cancer diagnosis, treatment, and cancer-related health risks. In addition, because of the relative rarity of childhood cancer, many health care providers lack familiarity with cancer-related health risks and risk-reduction methods relevant for this population. To correct these deficits, the Scottish Intercollegiate Guidelines Network (SIGN) and the Children's Oncology Group (COG) developed clinical practice guidelines to foster appropriate risk-based survivor care. Herein, we discuss the development, benefits, and limitations of the SIGN and COG guidelines and the foundation they provide for standardizing long-term follow-up care of the ever-growing vulnerable population of childhood cancer survivors.

Evaluating Survivors of Pediatric Cancer

The past 3 decades have seen tremendous improvements in the survival of children diagnosed with cancer, with the 5-year survival rate approaching 80%. This improvement in survival has resulted in a growing population of childhood cancer survivors. Use of cancer therapy at an early age can produce complications that may not become apparent until years later. Approximately two thirds of the survivors of childhood cancer experience at least one late effect and about one fourth experience a late effect that is severe or life-threatening, although psychosocial issues in survivors and family members are often underestimated and may be more prevalent. Long-term complications in childhood cancer survivors, such as impairment in growth and development, neurocognitive dysfunction, cardiopulmonary compromise, endocrine dysfunction, renal impairment, gastrointestinal dysfunction, musculoskeletal sequelae, and subsequent malignancies, are related not only to the specific therapy used but also may be determined by individual host characteristics. We review the known late effects in survivors of childhood in order to suggest reasonable starting points for the evaluation of specific long-term problems in this unique but growing population.

Hypothyroïdie après irradiation cervicale dans le traitement des cancers du nasopharynx et du sein : étude prospective à propos de 84 patients

PURPOSE

1/ To evaluate the incidence of hypothyroidism following radiotherapy in the management of breast and nasopharyngeal carcinomas, 2/ to define the role of a systematic post therapeutic screening.

PATIENTS AND METHODS

From January 1996 through March 2001 a systematic evaluation of the clinical and the biological thyroid function was performed on a cohort of 84 patients that received supraclavicular irradiation. Selected patients had either a mammary (37 cases) or a nasopharyngeal (47 cases) carcinoma. Initial work up included thyroid inspection and palpation, and biological tests: serum FT4 and TSH levels, radioimmunochemistry, completed by dynamic thyroid stimulation, using TRH, in case of border line low T4 or isolated high TSH levels. Tests were repeated every three months the first year, and then every six months. Replacement therapy with L Thyroxin was administered in case of hypothyroidism.

RESULTS

All selected patients had a normal function initially. With a mean two years follow up (1-5 years), 24 patients (29%) experienced hypothyroidism, half of whom (13 cases) being purely biological. Five patients (11%), with a nasopharyngeal carcinoma, presented also with associated pituitary failure. Clinical symptoms were minor or mild in all cases. Hypothyroidism was detected at a mean 21 months follow up. In 2 patients, hypothyroidism disappeared spontaneously within 6 months. Possible predictive factors were evaluated: age of the time of radiation, gender, percentage of irradiated thyroid, total dose, dose per fraction, tumour type and chemotherapy. Only age appeared significantly correlated with thyroid dysfunction (range: 10-30 years, P=0.002).

CONCLUSION

Hypothyroidism is a frequent and certainly underestimated complication following radiotherapy of the neck. In such patients, a systematic clinical and biological evaluation every three months the first year, and then every six months until five years is recommended.

Development of risk-based guidelines for pediatric cancer survivors: the Children's Oncology Group Long-Term Follow-Up Guidelines from the Children's Oncology Group Late Effects Committee and Nursing Discipline

The Children's Oncology Group Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers are risk-based, exposure-related clinical practice guidelines intended to promote earlier detection of and intervention for complications that may potentially arise as a result of treatment for pediatric malignancies. Developed through the collaborative efforts of the Children's Oncology Group Late Effects Committee, Nursing Discipline, and Patient Advocacy Committee, these guidelines represent a statement of consensus from a multidisciplinary panel of experts in the late effects of pediatric cancer treatment. The guidelines are both evidence-based (utilizing established associations between therapeutic exposures and late effects to identify high-risk categories) and grounded in the collective clinical experience of experts (matching the magnitude of risk with the intensity of screening recommendations). They are intended for use beginning 2 or more years following the completion of cancer therapy; however, they are not intended to provide guidance for follow-up of the survivor's primary disease. A complementary set of patient education materials ("Health Links") was developed to enhance follow-up care and broaden the application of the guidelines. The information provided in these guidelines is important for health care providers in the fields of pediatrics, oncology, internal medicine, family practice, and gynecology, as well as subspecialists in many fields. Implementation of these guidelines is intended to increase awareness of potential late effects and to standardize and enhance follow-up care provided to survivors of pediatric cancer throughout the lifespan. The Guidelines, and related Health Links, can be downloaded in their entirety at www.survivorshipguidelines.org.

[Absorbed dose evaluation of thyroid during nasopharynx and breast carcinoma irradiation by in vivo dosimetry]

AIMS

The thyroid dysfunction after radiotherapy has led to evaluate the dose received by thyroid during nasopharynx and breast carcinoma irradiation. This evaluation was facilitated by in vivo dosimetry. The aims of this work were to evaluate the thyroid dose and to compare released dose at the reference point in the two localizations.

PATIENTS AND METHODS

A total of 30 patients were evaluated: 18 patients with nasopharynx carcinoma and 12 patients with breast carcinoma were included in the final analysis. In the first group, the total thyroid but the isthmus was irradiated. On the other hand, in the second group, only one thyroid lobe was included into the target volume. All patients have been treated by gamma rays of cobalt 60 and the thyroid absorbed dose was measured by semiconductor dosimeters (Scanditronix DPD6). These dosimeters were calibrated in the same geometric conditions of the irradiation.

RESULTS

The measured absorbed dose of the thyroid parenchyma was equal to the calculated absorbed dose at the target that has been specified at a depth of -3 cm. Under the block, the isthmus received 5.1 +/- 0.9 Gy (9.9 +/- 1.8%) in nasopharynx carcinoma irradiation. However, in breast carcinoma irradiation, the distal thyroid lobe and the isthmus received 2.9 +/- 0.7 Gy (6.55 +/- 1.56%) and 3.69 +/- 0.77 (8.39 +/- 1.76%), respectively.

CONCLUSIONS

This study shows that the thyroid received a dose equal to the prescribed dose in both nasopharynx and breast cancer patients. It is recommended to follow the function of the thyroid gland in these patients.

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.

Endocrine complications of pediatric brain tumors: case series and literature review

The survival rate for childhood cancer, including brain tumors, is increasing. As a result, long-term sequelae of chemotherapy and radiotherapy are also increasing. The purpose of this study was to determine the frequency of endocrine complications of therapy for brain tumors in pediatric patients. Endocrinopathy was observed in 19 of 20 (95%) of patients with supratentorial midline tumors. Fifty-seven patients with nonmidline tumors (22 supratentorial, 35 posterior fossa) were followed for a mean of 4.6 +/- 2.4 years. Twenty-two endocrinopathies occurred in 16 patients treated as follows: one of 23 patients (0.4%) had surgery alone, zero of four (0%) had chemotherapy alone, eight of 18 (44%) had radiotherapy alone, and seven of 12 (58%) had both radiotherapy and chemotherapy. Endocrine disturbance was particularly common after craniospinal radiation (10 of 18 [55%]). Growth failure occurred in none of 23 patients who had surgery alone, in one of four patients who had chemotherapy (25%), in 11 of 18 patients who had radiotherapy (61%), in seven of 12 patients who received both radiotherapy and chemotherapy (58%), and in 12 of 18 patients who had craniospinal radiation (67%). In conclusion, endocrine and growth disturbances are uncommon with surgery alone, although they occurred in 53 and 60%, respectively, of patients treated with cranial irradiation for a brain tumor. This finding underscores the importance of routine endocrinology follow-up for all brain tumor patients receiving cranial irradiation. Literature review and endocrine surveillance recommendations are included.

Late endocrine, metabolic and skeletal sequelae following treatment of childhood cancer

With an ever increasing adult population of childhood cancer survivors there is a need to focus on the late effects of cancer therapy. It is essential that, after discharge from the paediatric oncologists, the patients are not lost from the health system but are under continued surveillance with access to the appropriate physicians. Endocrine and metabolic consequences may affect a patient's life both soon after cancer treatment and also for many years in the future. In this review we consider the following potential problems: growth hormone deficiency and replacement in adulthood, cardiovascular risk factors, osteopaenia, thyroid and parathyroid dysfunction.

Cranial irradiation and central hypothyroidism

Cranial irradiation causes thyrotropin (TSH)-releasing hormone (TRH) secretory abnormalities. TRH deficiency leads to abnormal glycosylation of TSH alpha and beta subunits and loss of the normal circadian pattern of TSH secretion (low in the afternoon, a surge in the evening, higher at night). This disruption results in either mixed hypothyroidism (raised TSH with abnormal secretory kinetics) or central hypothyroidism (abnormal secretory kinetics without raised TSH). Although primary hypothyroidism is more common in the general population and cancer survivors, the cumulative incidence of central and mixed hypothyroidism is high during the ten years after cranial irradiation. Monitoring for decline in free thyroxine (FT(4)) and rise in serum TSH, and early recognition using TSH surge and TRH tests, are clinically valuable. Early thyroid hormone replacement therapy to achieve serum FT(4) in the upper half of the normal range is crucial for maintaining optimal health and growth in cancer survivors.

Comparing thyroid ultrasonography to thyroid function in long-term survivors of childhood lymphoma

BACKGROUND

We studied the value of thyroid ultrasonography as a follow-up tool in survivors of childhood lymphomas and correlated morphologic abnormalities with thyroid function tests.

PROCEDURE

A prospective follow-up study of 45 long-term survivors of histology-proved childhood lymphomas was performed. Mean age at diagnosis was 9.1 years (range 2.1-16.4 years) and mean follow-up duration 10.9 years (range 3.9-22.2 years).

RESULTS

Among the 26 survivors of Hodgkin disease (HD) who received mantle field irradiation, 14 (54%) had abnormal ultrasonograms. Elevated thyroid-stimulating hormone (TSH) concentrations were found in 14 (54%), and 6 of them (42%) had normal thyroid functions. Six of twelve patients with normal ultrasonograms had abnormal thyroid function, and 5 of 11 patients with normal function had abnormal sonograms. Among the 19 non-HD survivors who did not receive radiotherapy, 18 (95%) had both normal sonograms and normal function. Thus thyroid gland abnormalities were detected in 54% of HD survivors after mantle field irradiation. No correlation between the abnormalities detected on ultrasonography and serum levels of TSH and thyroid hormones were found.

CONCLUSIONS

Both ultrasound and thyroid function tests independently provide clinically useful information; the former examines gland morphologogy and the latter evaluates hormonal changes associated with thyroid disease. The high frequency of thyroid abnormalities detected by ultrasonography suggests that periodic thyroid ultrasonography is advisable in the follow-up of patients treated with mantle irradiation to screen for morphologic changes that may presage malignant transformation.

[Late effects of ionizing radiations on the thyroid gland]

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.

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 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.

Growth and neuroendocrine dysfunction following therapy for childhood cancer

Poor linear growth and short adult stature are common complications following successful treatment of childhood cancer. Although several factors contribute to the impaired growth of these patients, growth potential is most reduced following radiotherapy to the head or spine. Younger age at treatment and female sex seem to be significant and independent risk factors for short adult height. Early diagnosis and timely therapy of the endocrine sequelae of cancer treatment (i.e., GH deficiency, hypothyroidism, and precocious puberty) ensure that these individuals will reach their optimum growth potential. For patients exposed to high-dose radiotherapy (> 35-40 Gy) to the region of the hypothalamus and pituitary gland, a variety of neuroendocrine abnormalities in addition to GH deficiency and early sexual development may occur, including deficiencies of LH/FSH, TSH, and ACTH as well as hypersecretion of prolactin. Because these problems may develop many years after irradiation, patients at risk for neuroendocrine disturbances require long-term endocrine follow-up.

Development of primary hypothyroidism with antithyroglobulin, antiperoxidase, and blocking-type thyrotropin receptor antibodies after radiation therapy for neuroblastoma

We describe a girl with hypothyroidism and blocking-type thyrotropin receptor antibodies that developed after chemotherapy and irradiation of the neck region for neuroblastoma. Results of thyroid studies before treatment were normal. Twenty months after completion of treatment, the girl had hypothyroidism with high titers of blocking-type thyrotropin receptor antibodies, antithyroglobulin, and antiperoxidase antibodies.

The influence of lymphangiography on the development of hypothyroidism in patients irradiated for Hodgkin's disease

PURPOSE

There is no consensus in the literature regarding the role of lymphangiography in promoting hypothyroidism in individuals with Hodgkin's disease irradiated with a mantle field. We sought to analyze the onset and rate of developing clinical or chemical hypothyroidism as well as possible factors related to its development in patients who received irradiation to the thyroid gland during treatment of Hodgkin's disease.

METHODS AND MATERIALS

One hundred and forty-two patients with Hodgkin's disease were treated at the Fox Chase Cancer Center between June 1967 and October 1993. All patients were treated with curative intent with radiation therapy using a mantle field. After exclusion of patients without available thyroid function tests, < 200 days of follow-up, or no radiation to the thyroid, 104 patients were eligible for analysis. Follow-up ranged from 7-170 months (median: 43 months). Sixty-seven patients had a lymphangiogram. Seventy-three patients were treated with radiation alone and 31 with radiation plus chemotherapy.

RESULTS

The actuarial 2-, and 5-year rates of biochemical hypothyroidism for all 104 patients were 18 and 37%, respectively. Forty patients developed hypothyroidism: 9 (23%) at < or = 1 year, 18 (45%) at < or = 2 years, and 33 (83%) at < or = 5 years. The actuarial 2-, and 5-year rates of biochemical hypothyroidism for patients who underwent a lymphangiogram were 23 and 42%, respectively, compared to 9 and 28%, respectively, for patients who received mantle irradiation without a lymphangiogram (p = 0.05). The effects of lymphangiogram, total thyroid dose, stage, chemotherapy, dose per fraction, energy, and age were evaluated for all patients by Cox proportional hazards regression analysis. The use of a lymphangiogram (p = 0.05) was the only variable that significantly influenced hypothyroidism.

CONCLUSIONS

This paper demonstrates in a multivariate analysis accounting for other potentially important variables the significant effect of lymphangiography and subsequent radiation therapy on the development of hypothyroidism. This information must be balanced with the fact that lymphangiograms remain a useful aid in assessing lymph node involvement, staging patients, and planning treatment fields.

Growth and final height after treatment for childhood Hodgkin disease

PURPOSE

To evaluate in children the impact of contemporary treatment for Hodgkin disease on the pattern of growth and final height.

PATIENTS AND METHODS

We studied 80 patients (54 males) aged <14 years at diagnosis, with newly diagnosed, pathologically confirmed Hodgkin disease, treated at a single institution. Forty six patients received chemotherapy (CT) + radiotherapy (RT), 23 patients received RT alone, and 11 patients received CT alone. Heights were obtained at diagnosis, at the end of treatment, 1, 2, and 3 years after the end of treatment and at attainment of final height. Heights were converted to age- and sex-adjusted SD scores (SDS).

RESULTS

There was a significant change in height SDS at the end of treatment compared to height SDS at diagnosis for all three groups (CT + RT: -0.33, p<0.001; RT: +0.09, p=0.027; CT: -0.24, p=0.012). Over the 3 years following treatment, the rate of change of height SDS was not statistically different between the three treatment groups. Final height SDS was decreased for patients receiving RT + CT (-0.41 SDS, p=0.02; n=31). The change in final height SDS for patients receiving RT or CT only was -0.36 (n=14) and +0.42 (n=4), respectively. Loss of final height SDS correlated with younger age at diagnosis (p=0.005). Patients receiving higher RT doses tended to fare worse (p=0.08).

CONCLUSIONS

Pediatric patients treated for Hodgkin disease with the combination of RT and CT suffer a small but significant decrease in their final height SDS. Younger patients and those treated with higher RT doses appear to experience the greatest loss of height potential.

Thyroid abnormalities after therapeutic external radiation

The thyroid gland is the largest pure endocrine gland in the body and one of the organs most likely to produce clinically significant abnormalities after therapeutic external radiation. Radiation doses to the thyroid that exceed approximately 26 Gy frequently produce hypothyroidism, which may be clinically overt or subclinical, as manifested by increased serum thyrotropin and normal serum-free thyroxine concentrations. Pituitary or hypothalamic hypothyroidism may arise when the pituitary region receives doses exceeding 50 Gy with conventional, 1.8-2 Gy fractionation. Direct irradiation of the thyroid may increase the risk of Graves' disease or euthyroid Graves' ophthalmopathy. Silent thyroiditis, cystic degeneration, benign adenoma, and thyroid cancer have been observed after therapeutically relevant doses of external radiation. Direct or incidental thyroid irradiation increases the risk for well-differentiated, papillary, and follicular thyroid cancer from 15- to 53-fold. Thyroid cancer risk is highest following radiation at a young age, decreases with increasing age at treatment, and increases with follow-up duration. The potentially prolonged latent period between radiation exposure and the development of thyroid dysfunction, thyroid nodularity, and thyroid cancer means that individuals who have received neck or pituitary irradiation require careful, periodic clinical and laboratory evaluation to avoid excess morbidity.

Care and treatment of long-term survivors of childhood cancer

With the advances in the therapy of childhood cancers over the past 30 years, many children who are now cured of their cancer are moving into adulthood. These patients have, in many cases, been exposed to multiple therapeutic modalities (chemotherapy, radiation, and/or surgery), and in recent years have experienced more and more intensive therapies. Potential late sequelae can involve almost any organ system, but can be predicted, in part, by the chemotherapy or radiation that individuals may have received. These complications may be categorized by their timing relative to the discontinuation of therapy: early (under 5 years), intermediate (5-20 years), or very late (over 20 years). Four potential late sequelae are reviewed (thyroid, cataracts, renal, and osteoporosis), and recommendations are made for screening of at risk individuals for these long-term complications. The need for long-term follow-up of this unique group of individuals is critical as we attempt to completely define the risks and benefits of our therapeutic efforts.

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.

The survivors of childhood solid tumors

With the improvement in cancer therapy in recent years, the number of cancer survivors is rapidly increasing. Potential late medical and psychosocial sequelae of cancer therapy are reviewed. A practical guide for the primary health care giver is provided.

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.

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.

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)

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.