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

Long-term biological effects after acute 131I-administration of two rat models (with and without thyroid)

PURPOSE

Radioiodine-131 (RAI or iodine-131) is one of the most frequently used radionuclides for diagnosis and therapy of thyroid diseases (90% of all therapies in nuclear medicine). In order to optimize the patient protection, it is important to evaluate the long-term biological effects of RAI therapy on non-target organs.

MATERIALS AND METHODS

An experimental animal model has been adopted, it consists on miming RAI therapy. An activity of RAI has been administrated in two models of Wistar rats: the first model with an intact thyroid gland (Thy + model), and the second one was thyroidectomized (Thy- model). For each model, 6 rats were orally contaminated with a solution 18.5 ± 1MBq of [131I]NaI and 6 others rats were used as controls. The 24 rats have been placed in individual cages for a period of 08 months then they were euthanized. The blood was collected by cardiac puncture and all organs were immediately removed. A fraction of thyroid, liver, kidneys and testicles was put in vials containing formaldehyde (10%) for histological investigation.

RESULTS

Histological observations show some liver disorders more accentuated in the case of the Thy- model, the appearance of kidney tissue effects (hemosiderin deposits, fibrosis and glomerular necrosis) for both models and an absence of any anomaly for the testicles slides. The disturbance of blood parameters specific to each organ has been revealed.

CONCLUSIONS

Long-term biological effect of 131I-administration shows the appearance of various histological disorders confirmed by disturbances in hepatic and renal functions.

Thyroid abnormalities in patients with Hodgkin lymphoma: The importance of close surveillance

INTRODUCTION

Survival in paediatric patients with Hodgkin lymphoma (HL) has increased over the last decades. However, these patients are at increased risk of developing late thyroid sequelae due to the treatment with irradiation and alkylating agents.

METHODS

We conducted an observational and retrospective study in patients with a diagnosis of HL between 2007 and 2022, in a hospital that is a paediatric oncology reference centre, through the review of electronic health records. We collected data on demographic (age, sex), clinical, radiological and histopathological variables, the dosage of alkylating agents and radiotherapy (RT) and on thyroid disorders using Microsoft Excel. The data analysis was conducted with SPSS version 17, using the Fisher exact test for qualitative data, a nonparametric test for quantitative data and Kaplan-Meier curves.

RESULTS

Sixty patients received a diagnosis of HL from 2007 to 2022. The median duration of follow-up was 78.5 months. There were 4 detected cases of hypothyroidism, 5 of thyroid nodules and 1 of subclinical hyperthyroidism. Treatment with RT was significantly associated with the development of hypothyroidism (P= .026), thyroid nodules (P= .01) and thyroid disease overall (P= .003). We estimated that the risk of thyroid disease increased 8-fold with each additional Grey received (hazard ratio, 1.081; 95% CI, 1.014-1.152; P= .017).

CONCLUSION

Hodgkin lymphoma patients treated with RT are at increased risk of late thyroid disorders, mainly hypothyroidism and malignancy. This risk is greater the higher the RT dosage and the longer the follow-up. We did not find evidence of an association between the use of alkylating agents and an increase in the risk of thyroid disease.

Characteristics and clinical course of thyroid abnormalities arisen in long term survivors of childhood cancer

BACKGROUND

Thyroid abnormality is a common late effect seen in childhood cancer survivors (CCSs). We analyzed the prevalence and risk factors of thyroid abnormalities based on diagnoses and treatment modalities in CCSs.

METHODS

The medical records of 257 CCSs who were diagnosed with cancer less than 20 year of age were retrospectively reviewed. The median age was 11.8 years (0.1-19.8). The median follow-up period after completion of therapy was 9.6 years (5.0-19.5).

RESULTS

Of 257 subjects, thyroid abnormalities were identified in 107 (41.6%). Sixty-five out of 257 (25.3%) had subclinical hypothyroidism, and 16 (6.2%) developed central hypothyroidism. Five CCSs (1.9%) had primary overt hypothyroidism. Five (1.9%) and 6 (2.3%) CCSs were diagnosed with autoimmune thyroiditis and thyroid cancer, respectively. Among the different diagnostic groups, thyroid abnormalities were frequent in the brain tumor or Hodgkin disease or nasopharyngeal cancer groups. CCSs who received irradiation directly or near hypothalamus-pituitary-thyroid (HPT) axis had more thyroid abnormalities compared to the rest CCSs (P < 0.0001). CCSs who were treated with SCT had an increased prevalence of thyroid abnormalities (60.5%) compared to the other CCSs (37.9%) (P = 0.0069). Forty-five (42%) of 107 subjects with thyroid abnormalities had normalized thyroid hormone levels at the last follow-up. Irradiation directly or near HPT axis were thought to be a predicting factor of persistent subclinical hypothyroidism.

CONCLUSIONS

Subclinical hypothyroidism was common in CCSs. CCSs with irradiation directly or near HPT axis were at risk for persistent thyroid dysfunction.

Predictive factors for thyroid complications after radiation therapy-data from a cohort of cancer patients closely followed since they were irradiated

INTRODUCTION

Cancer survivors are at an increased risk of adverse outcomes, including thyroid neoplasms, given the high radiosensitivity of this gland. The aim of this study is to assess the incidence and timeframe of thyroid complications in cancer patients, followed systematically since their radiation therapy, and to identify risk factors for the development of hypothyroidism and thyroid cancer.

METHODS

We performed a retrospective study, including 282 subjects, who received neck, craniospinal, or total body irradiation (TBI). Patients were grouped into four primary diagnostic clusters: leukaemia, Hodgkin's disease, central nervous system, and head and neck tumours.

RESULTS

Hypothyroidism was observed in 56.7% of patients, on average 6.8 ± 5.9 years after the treatment. Neck and craniospinal irradiation presented a 3.5-fold increased risk for the development of hypothyroidism compared to TBI. Papillary thyroid cancer was diagnosed in 8.5% of the patients, on average, 18.5 ± 4.9 years after radiotherapy (RT). Female gender, younger age, and lower irradiation doses were independently associated with thyroid cancer development.

CONCLUSION

Our study provides useful information about the risk of hypothyroidism and thyroid cancer after RT, as it was performed in a cohort of patients closely followed since the oncological therapies, and, thus, may give new insights into the follow-up management of these patients.

Identifying causal relationships of cancer treatment and long-term health effects among 5-year survivors of childhood cancer in Southern Sweden

Background

Survivors of childhood cancer can develop adverse health events later in life. Infrequent occurrences and scarcity of structured information result in analytical and statistical challenges. Alternative statistical approaches are required to investigate the basis of late effects in smaller data sets.

Methods

Here we describe sex-specific health care use, mortality and causal associations between primary diagnosis, treatment and outcomes in a small cohort (n = 2315) of 5-year survivors of childhood cancer (n = 2129) in southern Sweden and a control group (n = 11,882; age-, sex- and region-matched from the general population). We developed a constraint-based method for causal inference based on Bayesian estimation of distributions, and used it to investigate health care use and causal associations between diagnoses, treatments and outcomes. Mortality was analyzed by the Kaplan–Meier method.

Results

Our results confirm a significantly higher health care usage and premature mortality among childhood cancer survivors as compared to controls. The developed method for causal inference identifies 98 significant associations (p < 0.0001) where most are well known (n = 73; 74.5%). Hitherto undescribed associations are identified (n = 5; 5.1%). These were between use of alkylating agents and eye conditions, topoisomerase inhibitors and viral infections; pituitary surgery and intestinal infections; and cervical cancer and endometritis. We discuss study-related biases (n = 20; 20.4%) and limitations.

Conclusions

The findings contribute to a broader understanding of the consequences of cancer treatment. The study shows relevance for small data sets and causal inference, and presents the method as a complement to traditional statistical approaches.

Survivors of childhood cancer can develop late effects in adulthood. Knowledge about possible late effects can improve childhood cancer treatments and assist in follow-up. We developed a method to identify causative links between treatments and health outcomes. We applied it to a Swedish patient cohort and identified 98 causative links between treatments and outcomes, many of which are already known. Some, however, have not been previously described, including links between certain treatments and eye conditions or viral infections. We also confirm that childhood cancer survivors use more health care and have higher mortality compared to the general population. This study helps to create a better understanding of the late effects of cancer treatment in children and may help to guide strategies to monitor and treat children to avoid these effects.

Holst et al. study the relationship between cancer treatments and long-term health effects using registry data on childhood cancer survivors in Sweden. The authors utilize a causal inference approach to establish relationships between certain therapies and viral infections, eye conditions, and reproductive conditions, amongst others.

Maternal Thyroid Disease and the Risk of Childhood Cancer in the Offspring

Maternal thyroid disease, especially hypothyroidism, affects pregnancy and its outcome. In-utero exposure to autoimmune thyroid disease has been reported to associate with childhood ALL in the offspring. We evaluated the risk of childhood cancer in the offspring following exposure to maternal thyroid disease in a case-control setting using registry data. All patients with their first cancer diagnosis below the age of 20 years were identified from the Finnish Cancer Registry (n = 2037) and matched for sex and birth year at a 1:5 ratio to population controls identified from the Medical Birth Registry (n = 10,185). We collected national information on maternal thyroid disease from the Medical Birth Registry, Care Register for Health Care, Register for Reimbursed Drug Purchases and Register of Special Reimbursements. We used conditional logistic regression to analyze childhood cancer risk in the offspring. The adjusted OR for any childhood cancer was 1.41 (95%, CI 1.00-2.00) comparing the offspring of mothers with hypothyroidism and those with normal thyroid function. The risk of lymphomas was increased (adjusted OR for maternal hypothyroidism 3.66, 95%, CI 1.29-10.38). The results remained stable when mothers with cancer history were excluded from the analyses. Maternal hypothyroidism appears to be associated with an increased risk for childhood lymphoma in the offspring. The association exists even after excluding possible familial cancers.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Subclinical Hypothyroidism in Childhood Cancer Survivors

PURPOSE

In childhood cancer survivors, the most common late effect is thyroid dysfunction, most notably subclinical hypothyroidism (SCH). Our study evaluated the risk factors for persistent SCH in survivors.

MATERIALS AND METHODS

Survivors (n=423) were defined as patients who survived at least 2 years after cancer treatment completion. Thyroid function was assessed at this time and several years thereafter. Two groups of survivors with SCH were compared: those who regained normal thyroid function during the follow-up period (normalized group) and those who did not (persistent group).

RESULTS

Overall, 104 of the 423 survivors had SCH. SCH was observed in 26% of brain or nasopharyngeal cancer survivors (11 of 43) and 21.6% of leukemia survivors (35 of 162). Sixty-two survivors regained normal thyroid function, 30 remained as persistent SCH, and 12 were lost to follow-up. The follow-up duration was 4.03 (2.15-5.78) years. Brain or nasopharyngeal cancer and Hodgkin disease were more common in the persistent group than in the normalized group (p=0.002). More patients in the persistent group received radiation (p=0.008). Radiation to the head region was higher in this group (2394±2469 cGy) than in the normalized group (894±1591 cGy; p=0.003). On multivariable analysis, lymphoma (p=0.011), brain or nasopharyngeal cancer (p=0.039), and head radiation dose ≥1800 cGy (p=0.039) were significant risk factors for persistent SCH.

CONCLUSION

SCH was common in childhood cancer survivors. Brain or nasopharyngeal cancer, lymphoma, and head radiation ≥1800 cGy were significant risk factors for persistent SCH.

Late thyroid complications in survivors of childhood acute leukemia. An L.E.A. study

Thyroid complications are known side effects of irradiation. However, the risk of such complications in childhood acute leukemia survivors who received either central nervous system irradiation or hematopoietic stem cell transplantation is less described. We prospectively evaluated the incidence and risk factors for thyroid dysfunction and tumors in survivors of childhood acute myeloid or lymphoid leukemia. A total of 588 patients were evaluated for thyroid function, and 502 individuals were assessed for thyroid tumors (median follow-up duration: 12.6 and 12.5 years, respectively). The cumulative incidence of hypothyroidism was 17.3% (95% CI: 14.1-21.1) and 24.6% (95% CI: 20.4-29.6) at 10 and 20 years from leukemia diagnosis, respectively. Patients who received total body irradiation (with or without prior central nervous system irradiation) were at higher risk of hypothyroidism (adjusted HR: 2.87; P=0.04 and 2.79, P=0.01, respectively) as compared with transplanted patients who never received any irradiation. Patients transplanted without total body irradiation who received central nervous system irradiation were also at higher risk (adjusted HR: 3.39; P=0.02). Patients irradiated or transplanted at older than 10 years of age had a lower risk (adjusted HR: 0.61; P=0.02). Thyroid malignancy was found in 26 patients (5.2%). Among them, two patients had never received any type of irradiation: alkylating agents could also promote thyroid cancer. The cumulative incidence of thyroid malignancy was 9.6% (95% CI: 6.0-15.0) at 20 years. Women were at higher risk than men (adjusted HR: 4.74; P=0.002). In conclusion, thyroid complications are frequent among patients who undergo transplantation after total body irradiation and those who received prior central nervous system irradiation. Close monitoring is thus warranted for these patients. Clinicaltrials.gov identifier: NCT 01756599.

Ultrasound Evaluation of Thyroid Gland Pathologies After Radiation Therapy and Chemotherapy to Treat Malignancy During Childhood

PURPOSE

The purpose of this study was to evaluate correlations between treatment of malignancy by radiation therapy during childhood and the occurrence of thyroid gland pathologies detected by ultrasonography in follow-up examinations.

METHODS AND MATERIALS

Reductions of thyroid gland volume below 2 standard deviations of the weight-specific mean value, occurrence of ultrasonographically detectable thyroid gland pathologies, and hypothyroidism were retrospectively assessed in 103 children and adolescents 7 months to 20 years of age (median: 7 years of age) at baseline (1997-2013) treated with chemoradiation therapy (with the thyroid gland dose assessable) or with chemotherapy alone and followed by ultrasonography and laboratory examinations through 2014 (median follow-up time: 48 months).

RESULTS

A relevant reduction of thyroid gland volume was significantly correlated with thyroid gland dose in univariate (P<.001) and multivariate analyses for doses above 2 Gy. Odds ratios were 3.1 (95% confidence interval: 1.02-9.2; P=.046) for medium doses (2-25 Gy) and 14.8 (95% confidence interval: 1.4-160; P=.027) for high doses (>25 Gy). Thyroid gland dose was significantly higher in patients with thyroid gland pathologies during follow-up (P=.03). Univariate analysis revealed significant correlations between hypothyroidism and thyroid gland dose (P<.001).

CONCLUSIONS

Ultrasonographically detectable changes, that is, volume reductions, pathologies, and hypothyroidism, after malignancy treatment during childhood are associated with thyroid gland dose. Both ultrasonography and laboratory follow-up examinations should be performed regularly after tumor therapy during childhood, especially if the treatment included radiation therapy.

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.

Gestational doxorubicin alters fetal thyroid-brain axis

Administration of chemotherapy during pregnancy may represent a big risk factor for the developing brain, therefore we studied whether the transplacental transport of doxorubicin (DOX) may affect the development of neuroendocrine system. DOX (25 mg/kg; 3 times interaperitoneally/week) was given to pregnant rats during whole gestation period. The disturbances in neuroendocrine functions were investigated at gestation day (GD) 15 and 20 by following the maternal and fetal thyroid hormone levels, fetal nucleotides (ATP, ADP, AMP) levels and adenosine triphosphatase (Na(+), K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase) activities in two brain regions, cerebrum and cerebellum. In control group, the levels of maternal and fetal serum thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), and fetal serum growth hormone (GH) increased from days 15 to 20, whereas in the DOX group, a decrease in maternal and fetal T4, T3 and increase in TSH levels (hypothyroid status) were observed. Also, the levels of fetal GH decreased continuously from GD 15 to 20 with respect to control group. In cerebrum and cerebellum, the levels of fetal nucleotides and the activities of fetal ATPases in control group followed a synchronized course of development. The fetal hypothyroidism due to maternal administration of DOX decreased the levels of nucleotides, ATPases activities, and total adenylate, instead, the adenylate energy charge showed a trend to an increase in both brain regions at all ages tested. These alterations were dose- and age-dependent and this, in turn, may impair the nerve transmission. Finally, DOX may act as neuroendocrine disruptor causing hypothyroidism and fetal brain energetic dysfunction.

Salivary evaluation of pediatric patients with cancer, before and after antineoplasic treatment

AIMS

This study evaluated the salivary biochemical and immunological status of children with cancer undergoing to antineoplasic treatment in an attempt to identify alternatives for a less invasive and less painful monitoring of these patients.

MATERIALS AND METHODS

Unstimulated whole saliva samples were obtained from 115 children without cancer (control) and 32 children with cancer (CA). Children with cancer were also evaluated after antineoplasic treatment (CAT, n = 17). The salivary concentrations of glucose, triglycerides, total cholesterol, alkaline phosphatase, gamma-glutamyltransferase (GGT), urea, insulin, thyroid-stimulating hormone (TSH), triiodothyronine (T3), levothyroxine (T4), and immunoglobulin A (IgA) were determined.

RESULTS

Acute lymphocytic leukemia, acute myeloid leukemia, and Hodgkin's lymphoma were the most frequent cancers, although cases of non-Hodgkin's lymphoma, medulloblastoma, ependymoma, osteosarcoma, nephroblastoma, Ewing's sarcoma, and endodermal sinus tumor were also observed. The salivary concentration of cholesterol, triglycerides, or GGT did not differ between groups. Instead, the concentrations of alkaline phosphatase and T4 were higher in patients with cancer, irrespective of treatment. TSH levels were higher in the CA group and urea concentration was lower in the CAT group. T3 was undetectable in all groups. Antineoplasic treatment increased the glucose level and decreased the insulin concentration. Salivary concentration of total IgA was lower in children with cancer, irrespective of treatment.

CONCLUSIONS

Cancer and antineoplasic treatment affected biochemical and immunological parameters in the saliva of children, shedding new light on the potential usefulness of saliva for monitoring children with cancer, especially to patients undergoing immunosuppressive therapy.

Radiotherapy-induced hyperthyroidism in a cystinotic kidney transplant patient with Hodgkin lymphoma

Hypothyroidism is a well-known complication of cystinosis. PTLD incidence in pediatric renal transplant population ranges between 1 and 4.5%. We describe the case of a young cystinotic patient who developed hyperthyroidism after radiotherapy for Hodgkin lymphoma. He is a 23-yr-old male who was diagnosed with cystinosis at the age of two. He developed renal failure and other extrarenal complications but never presented hypothyroidism. At the age of 12, he received a successful kidney transplant from a cadaveric donor. Two yr later, EBV-positive Hodgkin lymphoma was diagnosed and chemotherapy and radiotherapy were administered. He achieved remission. Eight yr later, autoimmune hyperthyroidism secondary to previous radiation was detected, and he slowly became symptomatic. Clinical symptoms and laboratory data spontaneously normalized. This is the first case of a cystinotic patient developing hyperthyroidism. Thyroid disorders, especially hypothyroidism, have been reported in association with neck irradiation. Hypothyroidism would have been considered to be a late complication of cystinosis and not a consequence of radiotherapy. Thyroid hormones, clinical examination, and history evaluation for thyroid dysfunction should be periodically monitored after neck radiotherapy. The thyroid should always be excluded from the irradiation fields. Multidisciplinary interaction in difficult cases should be encouraged.

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.

Risk of thyroid dysfunction and subsequent thyroid cancer among survivors of acute lymphoblastic leukemia: a report from the Childhood Cancer Survivor Study

BACKGROUND

To determine the risk of thyroid dysfunction and subsequent thyroid cancer among childhood acute lymphoblastic leukemia (ALL) survivors.

PROCEDURE

Rates of self-reported thyroid dysfunction and thyroid cancer were determined among 3,579 ALL survivors participating in the Childhood Cancer Survivor Study, a cohort of 5-year survivors of pediatric cancers diagnosed from 1970 to 1986, and compared with 3,846 siblings and population rates, respectively.

RESULTS

The cumulative incidence of hypo- and hyperthyroidism among survivors 15 years following leukemia diagnosis was 1.6% (95% CI 1.1, 2.1) and 0.6% (95% CI 0.3, 1.1), respectively, both significantly increased compared with siblings. In multivariate analysis, survivors who received >or=20 Gy cranial radiotherapy plus any spinal radiotherapy had the highest risk of subsequent hypothyroidism (HR 8.3, 95% CI 3.3, 20.5) compared with those treated with chemotherapy alone. Craniospinal radiotherapy also was associated with an increased risk of subsequent hyperthyroidism (HR 6.1, 95% CI 1.1, 34.2) compared with chemotherapy alone, as well as an increased risk of subsequent thyroid cancers (SIR 30.3, 95% CI 14.5, 55.7) compared with population rates. In radiation dosimetry analysis, pituitary doses >or=20 Gy combined with thyroid doses >or=10 Gy were associated with hypothyroidism, whereas pituitary doses >or=20 Gy combined with thyroid doses >or=15 Gy were associated with hyperthyroidism.

CONCLUSIONS

The risk of thyroid dysfunction and thyroid cancer was increased among childhood ALL survivors treated with craniospinal radiotherapy. In these individuals, long-term surveillance is warranted as no obvious plateau in risk was seen, even after 25 years of follow-up.

Comprehensive clinical follow-up of late effects in childhood cancer survivors shows the need for early and well-timed intervention

BACKGROUND

Due to recent advances in treatment, nearly 80% of childhood cancer patients become long-term survivors. Studies on the late effects of survivors are under way worldwide. However, data on Asian survivors remain limited.

METHODS

Data on 241 survivors at the Long-term Follow-up Clinic in Severance Hospital, South Korea, were collected and late effects were confirmed by oncologists.

RESULTS

The median follow-up from diagnosis was 7.8 years. Late effects were identified in 59.8% of survivors and 23.2% had two or more late effects. Grade 3 or higher late effects were present in 10.8%. The most common late effects involved endocrine system (29.0%). Late effects were present in 95.7% of brain tumor survivors and 36.0% of Wilms' tumor survivors. Chemotherapy, hematopoietic stem-cell transplantation and radiotherapy were significant factors associated with the number and severity of late effects (P < 0.05). Brain tumor survivors had more severe late effects (P < 0.001), whereas Wilms' tumor survivors had fewer and milder late effects (P < 0.05).

CONCLUSION

The observation that over 50% of cancer survivors suffered from late effects during the short follow-up period and that a high frequency of endocrine late effects was present indicates the need for early and well-timed intervention of the survivors.

Caring for adult survivors of childhood cancer

OPINION STATEMENT

Improved survival for pediatric oncology patients is a remarkable achievement of modern medicine. This success can be credited to the introduction of multimodality therapy and newer risk-based therapies developed and tested through national research protocols. With improved survival has come recognition of the many long-term effects of cancer and its treatment, such as vital organ dysfunction, subsequent malignancies, and psychosocial deficits. Childhood cancer survivors are vulnerable to adverse health outcomes which may not become apparent until years after therapy. These events may manifest well into adulthood when these individuals rarely return to their initial cancer center or seek preventive medical care. Risk-based follow-up can offer early detection and/or intervention and provides an opportunity to reduce cancer-related morbidity and mortality. An understanding of the late effects of cancer therapy is increasingly important for the medical community, both generalists and specialists-adult and pediatric, to better care for the growing population of adult survivors of childhood cancer.

Endocrine sequelae of cancer and cancer treatments

INTRODUCTION

Exposure to cancer and its treatments, including chemotherapy and radiotherapy, may result in late adverse effects including endocrine dysfunction. Endocrine disorders are the most commonly reported long-term complications of cancer treatment, especially by adult survivors of childhood cancers. This review will explore the endocrinologic adverse effects from non-endocrine cancer therapies.

METHODS

Searches including various Internet-based medical search engines such as PubMed, Medline Plus, and Google Scholar were conducted for published articles.

RESULTS

One hundred sixty-nine journal articles met the inclusion criteria. They included case reports, systematic analyses, and cohort reports. Endocrine disorders including hypothalamus dysfunction, hypopituitarism, syndrome of inappropriate anti-diuretic hormone secretion, diabetes insipidus, growth hormone disorders, hyperprolactinemia, gonadotropin deficiency, serum thyroid hormone-binding protein abnormalities, hypothyroidism, hyperthyroidism, hypomagnesium, hypocalcemia, hyperparathyroidism, hyperparathyroidism, adrenal dysfunction, gonadal dysfunction, hypertriglyceridemia, hypercholesterolemia, diabetes mellitus, and glycosuria were identified and their association with cancer therapies were outlined.

DISCUSSION/CONCLUSIONS

The journal articles have highlighted the association of cancer therapies, including chemotherapy and radiotherapy, with endocrine dysfunction. Some of the dysfunctions were more often experienced than others. Especially in patients treated with radiotherapy, some endocrinologic disorders were progressive in nature.

IMPLICATIONS FOR CANCER SURVIVORS

Recognition and awareness of endocrine sequelae of cancer treatments may permit for early detection and appropriate follow-up care for cancer survivors, thus improving their overall health and quality of life.