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

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.

A case of hypothyroid Graves' disease following external radiation therapy to the cervical region

A case of hypothyroid Graves' disease occurred following external radiation therapy to the cervical region is described. Severe hypothyroidism developed in a 56-year-old man 6 months after external radiation therapy for submandibular cancer. Serological evaluation of thyroid autoimmunity revealed the presence of antithyroid antibodies and thyrotropin-binding inhibitory immunogloblins (TBII). Diplopia, limitation of downward gaze, and palpebral edema developed 2 years after levothyroxine replacement therapy. Ocular magnetic resonance imaging revealed marked hypertrophy of the bilateral extraocular muscles with signal hyperintensity on T2-weighted images. This infiltrative ophthalmopathy showed marked improvement after additional treatment with high-dose methylprednisolone and orbital radiation, in parallel with a decrease in TBII. These results suggest that radiation-associated thyroidal injury might be associated with the etiology of hypothyroid Graves' disease.

[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.

Autoimmune hyperthyroidism occurring late after radioiodine treatment for volume reduction of large multinodular goiters

131I treatment is an effective alternative to surgery in patients with a large, (non-)toxic, compressive goiter. Late development of hyperthyroidism after 131I therapy for nontoxic nodular goiter is considered rare. We have seen this complication in 3 of approximately 80 patients treated with radioiodine for volume reduction of a large, multinodular goiter. Three women, aged 60 to 71 years, had large, multinodular goiters causing tracheal compression. They were clinically euthyroid before 131I therapy and had normal free thyroxine (FT4) levels. Serum thyroid-stimulating hormone (TSH) levels were normal in 2 patients and undetectable in 1 patient. Patients 1 and 2 received a single dose of 86 and 48 mCi 131I, respectively. Patient 3 received 20 mCi 131I twice (interval 1 month). Clinical and biochemical thyrotoxicosis with high thyroid radioactive iodide uptake (RAIU) developed 10, 6, and 3 months after 131I therapy, respectively, although at control visits 1 to 3 months earlier, serum TSH and FT4 levels were normal. Thyrotoxicosis responded well to methimazole in all three patients. The late occurrence of thyrotoxicosis, high RAIU, and good response to methimazole argue against thyroiditis as the cause of thyrotoxicosis. Serum levels of TSH receptor antibodies, which were undetectable before therapy (patients 1 and 2), were clearly elevated in all three patients during thyrotoxicosis. This is in favor of autoimmune hyperthyroidism as the cause of thyrotoxicosis. These cases illustrate that severe autoimmune hyperthyroidism may occur several months after radioiodine treatment for nontoxic, multinodular goiter. Information about symptoms of hyperthyroidism and regular control visits in the first year after therapy are important in these patients.

Hodgkin's disease treated with neck radiation is associated with increased antibody-dependent cellular cytotoxicity against human extraocular muscle cells

Patients with Hodgkin's disease have higher a prevalence of thyroid function abnormalities and, perhaps, orbitopathy than the general population, but the pathophysiology of this association and its relationship to Hodgkin's disease treatment remain unclear. We analyzed the frequency of thyroid function abnormalities, autoantibodies against thyroid antigens, and autoimmunity against extraocular muscle cell antigens by Western blot analyses and antibody-dependent cellular cytotoxicity (ADCC) assays in patients with Hodgkin's disease (n = 20) and controls (n = 10). Hodgkin's disease patients were subdivided into those treated with thyroidal external beam radiation therapy (XRT, n = 15) or chemotherapy (MOPP/ABVD, n = 5). The ADCC assay against extraocular muscle cells was increased in patients with Hodgkin's disease (5.5% vs. <1.0%, p = .026) when compared with controls. In addition, Hodgkin's disease patients treated with XRT (with or without chemotherapy) had significantly higher ADCC tests than controls (9.7% vs. <1.0%, p = .010), In contrast, ADCC assays were not different between Hodgkin's disease patients treated with chemotherapy alone and controls (<1.0% vs. <1.0%, p = .53). Hodgkin's patients treated with XRT had higher ADCC assays than those treated with chemotherapy alone (p = .087), although this difference did not achieve statistical significance. Serum measurements of antithyroid peroxidase (TPO) antibodies, antithyroglobulin (Tg) antibodies, thyroid binding inhibitory immunoglobulins (TBII), and thyroid stimulating immunoglobulin (TSI) were similar in all groups. Antibodies against the 64 kDa orbital antigen were detected in 1 patient and 1 control subject. Excluding patients already treated with L-thyroxine for hypothyroidism (n = 5), free T3, but not free T4, was lower in the Hodgkin's disease group than in controls (2.2 pg/mL vs. 2.7 pg/mL, p = .008). Thyrotropin (TSH) concentrations were not statistically different between these groups. In summary, these data show: (1) ADCC against human orbital muscle cells is increased in patients with Hodgkin's disease compared with controls: (2) these differences were noted among Hodgkin's disease patients treated with thyroidal XRT, with or without chemotherapy, and not among those patients treated with chemotherapy alone; and (3) no statistically significant differences in the frequency of thyroid autoantibodies were found. These data suggest that patients with Hodgkin's disease display altered antibody-dependent immune function toward extraocular muscle cells that may possibly be related to by XRT. Larger, prospective studies assessing thyroid and orbital-related immunologic abnormalities in Hodgkin's disease are warranted.

Thyroid diseases after treatment of Hodgkin's disease

BACKGROUND AND METHODS

Thyroid disease, especially hypothyroidism, is common in patients with Hodgkin's disease who have been treated with irradiation. We reviewed the records of 1787 patients (740 women and 1047 men) with Hodgkin's disease who were treated with radiation therapy alone (810 patients), radiation and chemotherapy (920 patients), or chemotherapy alone (57 patients) at Stanford University between 1961 and 1989. Among these patients, 1533 were alive at the last follow-up, and 254 had died of causes other than Hodgkin's disease. (Four other patients were excluded from the analysis because they had undergone thyroidectomy before treatment for Hodgkin's disease. The thyroid was irradiated in 1677 patients. Follow-up averaged 9.9 years.

RESULTS

A total of 573 patients had clinical or biochemical evidence of thyroid disease. Among the 1677 patients whose thyroid was irradiated, the actuarial risk of thyroid disease 20 years after treatment was 52 percent, and it was 67 percent at 26 years. Hypothyroidism was found in 513 patients. A total of 486 patients received thyroxine therapy for elevated serum thyrotropin concentrations and either low free thyroxine (208 patients) or normal free thyroxine values (278 patients); 27 had transient elevations of the serum thyrotropin level that were not treated. Graves' hyperthyroidism developed in 30 patients (2 of whom had not undergone thyroid irradiation), and ophthalmopathy developed in 17 of these patients. Ophthalmopathy developed in four other patients with Graves' disease during a period of hypothyroidism (n = 3) or euthyroidism (n = 1). The risk of Graves' disease was 7.2 to 20.4 times that for normal subjects. Silent thyroiditis with thyrotoxicosis developed in six patients. Forty-four patients were found to have single or multiple thyroid nodules, 26 of whom underwent thyroidectomy. Six of the 44 had papillary or follicular cancers. Among the patients who did not undergo operation, 12 had small functioning nodules, 4 had cysts, and 2 had multinodular goiters. The actuarial risk of thyroid cancer was 1.7 percent. The risk of thyroid cancer was 15.6 times the expected risk.

CONCLUSIONS

High risks of thyroid disease persist more than 25 years after patients have received radiation therapy for Hodgkin's disease, reinforcing the need for continued clinical and biochemical evaluation. Prolonged follow-up confirms an elevated risk of thyroid cancer and Graves' disease as well as hypothyroidism in these patients.

Hypothyroidism in the elderly

This review describes the changes in thyroid physiology with aging and notes that normal thyroid status is maintained with advanced age. The increased frequency of hypothyroidism in the elderly is stressed with consideration given to the multiple possible etiologies. The natural history of hypothyroidism is considered as evidenced by the various hormonal abnormalities in subjects with autoimmune thyroiditis and patients previously treated with radioiodine. The potential significance of subclinical hypothyroidism is discussed in regard to nonspecific symptoms and subtle cardiovascular manifestations. The problems in the clinical and laboratory diagnosis of hypothyroidism are reviewed with emphasis on the high index of suspicion and cautious interpretation of plasma thyroxine and thyroid-stimulating hormone (TSH) levels required. Finally the potential problems in treating hypothyroidism in the elderly are discussed in regard to dosage requirements and the need to avoid subclinical hypothyroidism by using the ultrasensitive TSH assay.

Incidence of hypothyroidism after irradiation of the neck with special reference to lymphoma patients. A retrospective and prospective analysis

Twenty-eight patients were studied prospectively in order to determine the incidence of hypothyroidism after mantle irradiation for malignant lymphoma. This group was compared with a historical group of 65 patients, among them 36 patients with malignant lymphoma. The mean follow-up was 30 months for the prospective group and 46 months for the retrospective group. The mean thyroid dose for irradiated malignant lymphomas in the prospective and the retrospective group was 45 Gy and 43 Gy respectively. For other tumors with neck irradiation (retrospective group) the mean thyroid dose was 53 Gy. There were no cases of clinical hypothyroidism in our study. As for subclinical hypothyroidism which is characterised by elevated TSH, the incidence was 22% in the prospective group and 3% in the retrospective group, i.e. 8/93 patients showed a hypothyroid dysfunction. Three of the 8 patients with subclinical hypothyroidism had undergone lymphangiography before radiotherapy. Due to the elevated iodine pool a lymphangiogram is considered as a risk factor for hypothyroidism as well as for hyperthyroidism, which we observed twice in the prospective group. Evaluation of the thyroid function before lymphangiography and irradiation as well as regular thyroid function studies during the follow-up are recommended in order to detect hypothyroidism in time.

Treatment of non-toxic multinodular goiter with radioactive iodine

Fourteen patients with large non-toxic multinodular goiters were treated with 20 to 100 mCi (740 to 3,700 MBq) of radioactive iodine (iodine-131). In seven, the goiter had recurred after a partial thyroidectomy and four of these had had two operations. Eight had symptoms of respiratory obstruction, two had dysphagia, and the others sought treatment for cosmetic reasons. After administration of iodine-131, there was a significant decrease in goiter size in 11 of the 14 patients, and all those with obstructive symptoms showed improvement. No significant local side effects occurred, but hypothyroidism and Graves' disease each occurred once during follow-up from one to 13 years. Radioactive iodine in doses of 20 to 100 mCi is an effective, safe therapeutic alternative in patients with large non-toxic multinodular goiter, particularly when there is recurrence following surgery or when there are contraindications to surgery.