THYROID CANCER IN LEBANESE CHILDREN AND ADOLESCENTS: A 15-Year Experience at a Single Institution

Background and Aim: Thyroid carcinomas are rare in childhood and adolescence. Management of this entity remains controversial. The aim of this study is to review our experience with multidisciplinary management of papillary thyroid cancer in the pediatric population at a tertiary care specialized medical center in Lebanon. Procedure: The medical records of all patients with thyroid cancer younger than 20 years who presented to our center between January 1991 and January 2006 were reviewed. Results: Thirteen patients with papillary thyroid carcinoma (PTC) were identified. No patient had previous exposure to ionizing radiation. The mean age at diagnosis was 14.5 years. There were 8 females; all patients presented with a cervical mass. Ten patients underwent total thyroidectomy and three subtotal thyroidectomy. Eight patients (61.5%) had regional lymph node metastases, only one of whom (7.6%) had lung metastases. All received radioactive “131I” ablation postsurgical excision. Five (38.5%) had recurrences and needed multiple surgeries and/or “131I” ablation. At a median follow-up time of 8.3 years all patients are disease free. Conclusion: Pediatric thyroid cancer in Lebanon is a rare tumor that presents mainly as a primary malignancy. The main clinical presentation is a cervical mass with locoregional lymph nodes metastasis. The mainstay of therapy is total thyroidectomy with lymph node dissection when indicated and radioactive “131I” ablation. Despite recurrences the prognosis is excellent.     

Management of childhood and adolescent thyroid carcinoma: long-term follow-up and clinical characteristics.

AIM: This analysis was performed to evaluate clinical factors such as local tumor control, control of distant metastasis, survival, and complications in children and adolescents with thyroid carcinoma. MATERIALS AND METHODS: From 1960 to 2003, 21 children and adolescents (16 girls and 5 boys, aged 4 to 15 years) were treated for thyroid carcinoma in our departments. Clinical data, operative findings, pathological findings, operative procedures, intra- and postoperative complications and follow-up were evaluated. Follow-up of patients ranged from 3 to 42 years (median, 20 years). RESULTS: Papillary carcinoma was found in 20 patients (95%) and follicular carcinoma in one patient. Cervical lymph node metastases were found in 12 out of 21 patients (57.1%) when thyroid carcinoma was diagnosed, and 5 patients (23.8%) had pulmonary metastasis. In patients with pulmonary metastasis, total thyroidectomy and bilateral radical lymph node resection was performed in 3 patients, lobectomy of the thyroid and radical lymph node resection in one patient, and partial thyroidectomy in one patient. All three patients who underwent total thyroidectomy are still alive. Internal irradiation by 131I and thyroid hormone replacement therapy was administered to 2 of 3 patients with pulmonary metastasis. CONCLUSION: Despite metastasis in the lymph nodes and even the lungs, the prognosis for patients with papillary carcinoma is good. Total thyroidectomy and positive 131I therapy are recommended for childhood and adolescent thyroid carcinoma with pulmonary metastasis.     

Differentiated thyroid cancer

Objective: The retrospective analysis of the case files of children with differentiated thyroid carcinoma (DTC) was performed to define the disease by its presentation, clinical course and outcome of radioiodine therapy.Methods: Between 1967 to October 2002,1754 patients with thyroid cancer were treated in the Dept of Neuclear Medicine, AIIMS, out of which 122 (7%) were ≶ 20 years of age (71 girls and 51 boys). The mean age was 15.8 ± 3.6 years and the mean duration of follow-up was 90 ± 59.3 months. Mean tumor size was 4.4 cm. Histologically, 85% of the patients had papillary and rest follicular carcinoma. Cervical lymph node involvement was seen in 64%, and distant metastases, mainly pulmonary, in 23% of the patients. The presentation of the disease was very aggressive in the first decade of life with male preponderance. All but one patient in this age group had nodal and/or distant metastases; in 83.3% the disease had spread to the lymph nodes and 67% had metastases to the lungs. The post-surgery 48-hour mean radioiodine neck uptake was 10.5 ± 7.6%.Results: 94% of the residual thyroid, 88% of nodal metastases and 71% of pulmonary metastases were ablated requiring mean cumulative doses of 2.8 ± 2.7 GBq, 4.5 ± 2.7 GBq and 10.4 ± 7.9 GBq of¹³¹I, respectively. Average number of doses required for remnant, nodal and pulmonary metastases ablation were 1.3, 2.2 and 3.3, respectively. 80% of the patients with only remnant thyroid tissue and 50% with cervical lymph node metastases got ablated with a single dose of¹³¹I. Overall, 87% patients were currently free of disease. While, nine patients had nodal recurrence between surgery and radioiodine treatment, no recurrence was observed thereafter and 3 disease related deaths producing overall mortality of 2.5% (all in children ≶10 years of age) were seen in the mean follow-up of 7.5 years.Conclusion: Differentiated thyroid cancer in children and adolescents is rare but aggressive. The biological behavior differs from that in adults and is related to the age. Younger the age (≶10 years), more aggressive and widespread is the disease with male preponderance and high mortality. The Post-surgical radioiodine ablation/therapy is an important and effective adjuvant in the management of DTC in children and adolescents and even though they present with advance disease, long-term survival and overall prognosis is good.     

小儿分化型甲状腺癌的外科治疗策略

目的 探讨小儿甲状腺癌的临床特点，选择恰当的外科治疗方法，减少合并症的发生。方法 回顾性分析1975年7月～1997年12月我院头颈外科治疗的15岁以下31例小儿分化型甲状腺癌的临床资料、根据病变范围程度，选择腺叶峡部切除，次全切除或近全切除，甲状腺全切除治疗甲状腺原发灶，颈淋巴结转移行根治性或改良根治性清扫术。颈淋巴结清扫术的范围包括Ⅱ，Ⅲ，Ⅳ，Ⅴ和Ⅵ区。远处转移行Ⅰ或甲状腺素治疗。结果 31例中乳头状癌25例，滤泡癌6例，术后随访5～27年，平均随访13年8个月，无死亡病例。局部复发2例，颈部复发1例，复发率为9．7％(3／31)。颈淋巴结转移率为74．2％(23／31)，甲状腺外浸润占58．1(18／31)。全甲状腺切除的合并症为42．9%(3／7)，腺叶及次全切除合并症为8．3％(2／24)。结论 小儿分化型甲状腺癌病程长，转移率高，甲状腺外浸润较成年人更常见，但预后较成人好。主张行腺叶及次全切除术或近全切除，癌在甲状腺外侵及的器官及神经应尽可能保留其功能的完整，少许残留癌可行Ⅰ或甲状腺素治疗。     

Thyroid carcinoma in children and adolescents

A clinical and pathological study was undertaken to define the prevalence, clinical presentation and outcome of thyroid carcinoma in children and adolescents. Clinical records from 48 patients under 20 years of age at diagnosis, out of 372 patients with thyroid cancer examined between 1980 and 1994, were retrospectively reviewed. Female/male ratio was 3.8/1. None had a previous positive history of head and neck irradiation. Patients underwent near-total (44 patients) or partial (4 patients) thyroidectomy followed by ¹³¹I ablation of residual thyroid tissue. The mean follow up period was 58.4 months, ranging between 2 and 190 months. Clinically a thyroid mass was present in 41 patients, 28 of whom also showed neck lymph node involvement. Node metastases were present in 50% of the patients and lung metastases in 4.2%. Histological type was papillary in 41, follicular in 6, and medullary in 1 case. Surgical complications were observed in 19 patients (40%). In 3 patients papillary thyroid cancer was associated with chronic lymphocytic thyroiditis. All patients were treated with l-thyroxine suppressive therapy. Recurrence of cancer after surgical and radio-iodine treatment was observed only in one patient 8 months after surgery. Conclusion Our experience demonstrates that thyroid carcinoma in childhood cannot be considered a rare occurrence, since it represents about 13% of all thyroid cancers, and is frequently associated with lymph node but rarely with distant metastases. Nevertheless, the prognosis of thyroid carcinoma in childhood is fairly good. Received: 16 January 1996 / Accepted: 1 July 1996     

Differentiated thyroid cancer in childhood: pathology, diagnosis, therapy

The incidence of thyroid cancer in childhood amounts to approximately 0,5/100.000/year. However, after exposure to ionizing irradiation, the incidence may increase more than 20 fold. In children, lymph node metastases of differentiated thyroid cancer are frequent (more than 50%); distant metastases mainly to the lung are seen in 20-30%. The method of choice for the primary diagnosis of thyroid cancer today is ultrasonography with 7,5 - 10 MHz probes, accompanied by fine-needle aspiration biopsy. Differentiated thyroid cancer has to be treated with a multidisciplinary approach comprising total thyroidectomy and lymph node dissection, post-operative radioiodine treatment and TSH-suppression by levothyroxine. The long-term results of this treatment approach are generally good with 10-year survival rates of 95% and higher. The treatment of children with disseminated pulmonary metastases however, may be complicated due to the increased risk of the induction of pulmonary fibrosis by radioiodine.     

儿童分化型甲状腺癌综合治疗的探讨

目的 探讨儿童甲状腺癌的临床特点及合理的综合治疗方法.方法 回顾性分析了我院2000年1月～2008年1月收治的14岁以下37例分化型甲状腺癌的临床资料.1例甲状腺滤泡状癌仅行双侧甲状腺全切术;36例甲状腺乳头状癌行双侧甲状腺全切,根据肿块及淋巴结的情况行不同范围的颈淋巴结清扫术.手术后根据情况决定131 Ⅰ治疗及TSH抑制治疗的程度.结果 术后并发症总的发生率为5.4%(2/37).术后病理检查97.3%(36/37)为甲状腺乳头状癌,2.7%(1/37)为甲状腺滤泡状癌;多灶性癌的发生率为32.4%;淋巴结转移率为91.9%(34/37).平均随访3.8年,无死亡病例,18.9%(7/37)出现颈淋巴结复发转移,8.1%(3/37)出现远处脏器转移.结论 儿童甲状腺预后较好,治疗应采取双侧甲状腺全切加不同范围颈清扫的手术为中心,结合内分泌治疗和131 Ⅰ内照射治疗的综合治疗.     

Pediatric thyroid carcinoma: 22 years of experience at the Northern Israel Oncology Center (1973-1995)

Over the past 22 years, 16 children with thyroid carcinoma were referred to the Northern Israel Oncology Center. All patients had undergone surgical procedures, either total or subtotal thyroidectomy, and 7 patients had undergone cervical lymph node dissections. Postoperatively, 5 patients underwent thyroid ablation with radioactive ¹³¹I as first treatment. Two patients received postoperative external radiation therapy to a field encompassing the cervical region, superior mediastinum, and both supraclavicular grooves. After a median follow-up of 60 months (range, 5-169 months), all patients are alive with no evidence of recurrent disease. Two patients who had recurrences, one in the submaxillary lymph nodes and one in the lungs, were salvaged successfully with retreatment with ¹³¹I therapy. No severe acute or long-term side effects were exhibited. The long-term results of treatment of pediatric thyroid carcinoma are excellent, but there remains disagreement over the extent of surgical and postsurgical treatment required.     

Importance of thyroglobulin levels for diagnosis and monitoring of follicular thyroid carcinoma in an adolescent with severe iodine deficiency

Optimal management of differentiated thyroid cancer in childhood is undetermined. During monitoring of thyroid carcinoma, serum thyroglobulin (hTG) levels provide valuable information. hTG levels not only increase in differentiated thyroid cancers but also in iodine deficiency because of compensation by the thyroid gland. A 14.6 year-old girl was diagnosed with nodular goiter, subclinical hypothyroidism and severe iodine deficiency. She had a very high hTG level. Despite benign fine-needle aspiration biopsy (FNAB), because the hTG level was still very high after treatment with LT4, thyroidectomy was undergone. Cytopathological examination showed minimally invasive follicular thyroid carcinoma. During follow-up, to exclude the presence of persistent/recurrent disease, the hTG level rose to an undesirably high level after withdrawal of TSH suppressive therapy, and radioiodine ablation therapy was applied. This report shows that even if there is an explanation for nodular goiter and high hTG levels, such as iodine deficiency, malignancy cannot be ruled out without thyroidectomy. FNAB is not reliable especially in iodine deficient areas. Serum hTG measurement is a valuable tool for both diagnosis and follow-up of differentiated thyroid carcinoma in children.     

PEDIATRIC THYROID CARCINOMA: 22 Years of Experience at the Northern Israel Oncology Center (1973-1995)

Over the past 22 years, 16 children with thyroid carcinoma were referred to the Northern Israel Oncology Center. All patients had undergone surgical procedures, either total or subtotal thyroidectomy, and 7 patients had undergone cervical lymph node dissections. Postoperatively, 5 patients underwent thyroid ablation with radioactive ¹³¹I as first treatment. Two patients received postoperative external radiation therapy to a field encompassing the cervical region, superior mediastinum, and both supraclavicular grooves. After a median follow-up of 60 months (range, 5-169 months), all patients are alive with no evidence of recurrent disease. Two patients who had recurrences, one in the submaxillary lymph nodes and one in the lungs, were salvaged successfully with retreatment with ¹³¹I therapy. No severe acute or long-term side effects were exhibited. The long-term results of treatment of pediatric thyroid carcinoma are excellent, but there remains disagreement over the extent of surgical and postsurgical treatment required.     

Differentiated thyroid carcinoma: presentation and follow-up in children and adolescents

To review our Pediatric Endocrinology Division's experience with differentiated thyroid carcinoma (DTC) we analyzed retrospectively the records of patients with DTC that had been seen between June 1988 and June 2008. RESULTS: Forty-five patients (median age 13.7 years, 36 female) were diagnosed (papillary: 40, follicular: 5) with DTC presenting as a solitary nodule (n: 25), thyroid nodule with cervical adenopathy (n: 9) and multinodular goiter (n: 11). All underwent total thyroidectomy with resection of suspicious cervical lymph nodes (CLN). DTC was multicentric in 59% and revealed extrathyroidal extension in 44%. Initially, 44% had CLN metastases and 24% distant metastases. All patients underwent thyroid remnant ablation with 131I and suppressive treatment. Median follow-up was 5.1 years with a disease-free survival rate at 5 years of follow-up of 75%. Eleven percent presented recurrences. CONCLUSION: Pediatric DTC has an aggressive behavior at presentation. Higher preoperative TSH levels were significantly associated with a more advanced disease at diagnosis. CLT was present concomitantly in a quarter of the patients and further studies are needed to establish differences in these patients' outcome. Diagnostic approach, total thyroidectomy, 131I treatment and thyrotropin suppression allowed a good progression-free survival rate.     

Importance of early diagnosis and follow-up in multiple endocrine neoplasia (MEN II B)

Three patients with a sporadic form of multiple endocrine neoplasia (MEN) IIb are presented. MEN IIb is the association of medullary carcinoma of the thyroid (MTC), pheochromocytoma and multiple mucosal neuromata.The age at diagnosis and primary therapy of MTC was relatively late (8, 16, 18 years) although thyroid enlargement (two cases), typical marfanoid habitus (two cases) or multiple mucosal neuromata (one case) had been evident since early childhood. The diagnosis was confirmed by measurements of tumour markers like calcitonin (CT) and carcinoembryonic antigen (CEA) for MTC, measurements of vanillylmandelic acid for pheochromocytoma, evaluation of the thyroid gland by sonography, scintigraphy and fine needle biopsy, and investigation of the adrenals by computer tomography and meta-(I-131) iodobenzylguanidine (I-131-MIBG) scintigraphy.After surgical treatment determinations of tumour markers confirmed relapses of MTC in all cases.Early diagnosis of MEN IIb, which could be made by recognition of the typical clinical appearance, is of special importance because of the poor prognosis of MTC.Abbreviations MEN Multiple endocrine neoplasia - MTC medullary carcinoma of the thyroid - CT calcitonin - CEA carcinoembryonic antigen - VMA vanillylmandelic acid - I-131 MIBG meta (I-131) iodobenzylguanidine - MMN multiple mucosal neuroma syndrome     

Graves' disease in childhood

The vast majority of thyrotoxicosis cases in children are caused by Graves' disease (GD) and these account for 10-15% of all childhood thyroid diseases. The major clinical features of thyrotoxicosis in children are, in general, similar to those in adults. As in adults, the three conventional methods of treatment are antithyroid drugs (ATD), thyroidectomy and ablative radioiodine (131I). Although ATD are associated with side effects and a high relapse rate even after prolonged therapy, they still seem to be chosen as the first line of therapy for GD in childhood by most pediatric endocrinologists, although some have started using 131I as their first therapeutic modality. However, when ATD therapy has to be discontinued, or after relapse which may occur during or following ATD therapy, a definitive mode of therapy has to be chosen. Since thyroidectomy has the disadvantages of hospitalization and surgical complications, there is now an increasing tendency to advocate radioiodine as a choice of treatment in children older than five years old who achieve a high rate of remission. It should be kept in mind that with both thyroidectomy and radioiodine treatment, permanent hypothyroidism is very common and requires lifelong replacement therapy. According to the long-term follow-up data which have been published, radioiodine treatment in older children and adolescents seems to be safe and effective. Although studies of children with GD treated with ablative doses of radioiodine have not revealed an apparent increased risk of thyroid malignancy, a long-term study of larger populations is needed in order to define the true incidence of thyroid neoplasia, and other possible side effects, in children treated with radioiodine. Although the relatively low risks, low cost and practicability of radioiodine treatment has favored this therapy for children, as it has for adults, in the United States, it is still less attractive for European physicians. Progress in the immunological understanding of GD and of its genetic background will hopefully elucidate the pathways leading to GD, as well as the factors determining who is at high risk of developing GD, and may thus ultimately promote novel strategies for a more successful and safe therapy.     

Differentiated thyroid cancer in children and adolescents: the importance of adequate surgery and review of literature.

Within 25 years, 13 girls and 5 boys between the ages of 9 to 20 years were treated for differentiated thyroid cancer (DTC) at our institution. In 67% of the cases the diagnosis was made at an advanced stage indicated by cervical lymphnode metastases, two children showed metastases of the lung. Except for one girl, all patients underwent a total thyroidectomy with various forms of lymph node dissections. All were treated post-surgically with radio-iodine (131I) and all patients received levothyroxine in suppressive doses. The complication rate was low (laryngeal nerve injury in only 3 cases and no permanent hypoparathyroidism) and after a follow-up period of 26 years all patients are alive and without disease. In the case of DTC in children and adolescents, a total thyroidectomy with an appropriate lymph node dissection is the best surgical management. Besides the rather high incidence of local and distant recurrence, particularly in this age group, the detection and treatment of the metastases with radio-iodine are significantly facilitated by this surgical procedure. Additionally it allows the use of serum thyroglobulin as a reliable indicator of recurrence. To prevent high complication rates, surgical treatment should be performed in centers with skilled and experienced endocrine surgeons.     

Thyroid carcinoma

Eleven cases of thyroid cancer occurring in patients below 15 years of age are presented. The youngest patient was 4 years old. There were 4 boys and 7 girls in the study group. None of the patient had received head and neck irradiation. All patients had well differentiated cancers; there were 4 follicular carcinomas and 3 of these occured in patients below 10 years of age. Six patients presented with solitary thyroid nodules. Lymph node involvement had occurred in 63.7% of cases. One patient presented with CNS metastasis. Treatment aimed at near total thyroidectomy was performed in 9 patients. Two patients died of the disease during the follow up period and another 3 patients are alive. Postoperatively radioactive iodine was routinely used for evaluating and treating residual and recurrent disease.     

Anaplastic transformation from papillary thyroid carcinoma with increased serum CA19-9

A 24-year-old woman presented with anaplastic transformation from papillary thyroid carcinoma with increased serum CA19-9. The patient had been diagnosed as having papillary thyroid carcinoma with lung metastasis at 11 years of age. She received a total thyroidectomy with cervical lymph node dissection followed by iodine-131 ((131)I) therapy over 12 years, but died due to sudden onset of rapid dissemination. Elevated serum CA19-9 was detected in the terminal stage, and anaplastic transformation was confirmed by post-mortem examination. Although there are few clinical reports suggesting a prognostic indicator for anaplastic thyroid carcinoma, CA19-9 may be a useful serum marker for this tumor.     

Thyroidal uptake and radiation dose after repetitive I-131-MIBG treatments: influence of potassium iodide for thyroid blocking

BACKGROUND: In I-131-MIBG therapy, I-131-iodide can be released from the I-131-MIBG molecule. Hypothyroidism might result from the undesirable irradiation of the thyroid gland. To prevent this, stable iodide such as potassium iodide (KI) is given to oversaturate the thyroid before I-131-MIBG is administered. PROCEDURE: In the present study, the incidence of hypothyroidism (elevated TSH) was correlated with the thyroidal uptake of I-131 and dose (MIRD dosimetry) after 35 individual treatments in ten patients. Iodine-131-MIBG therapy was performed using a modified dosage of 1.9-11.1 GBq (50-300 mCi) IV. Premedication with KI was done as recommended with a dose of 100 mg KI orally from 2 days before until 4 weeks after I-131-MIBG. RESULTS: The absorbed thyroidal dose amounted to a very variable range of 0.2 (patient # 1) up to 30.0 (patient 3) Gy with 7.1 +/- 7.9 Gy per treatment and 24.1+/- 19.2 Gy per patient (mean+/- SD), despite the same and compliantly taken KI premedication protocol. Up to now, 4/10 or 40% of patients have developed hypothyroidism after a mean follow-up period of 11 months and a mean total administered dose of 18.7 GBq (505 mCi). A trend towards higher thyroidal doses was seen in the hypothyroid patients. CONCLUSIONS: This study observes a general high inter- and intra-individual variability in radio-iodide uptake in the thyroid after I-131-MIBG therapy despite KI premedication, as well as possible occurrence of hypothyroidism. A dose-response relationship needs confirmation on a larger cohort of patients to reach statistical value. An alternative thyroid cytoprotection strategy for possible long-term survivors may be considered.     

The usefulness of serum thyroglobulin in the follow-up of differentiated thyroid carcinoma in children.

Serum thyroglobulin has been measured serially in ten children aged 5-17 years presenting with differentiated thyroid carcinoma. At presentation 4 had intra-thyroidal disease, 3 had lymph node metastases, and 3 had lung metastases. During follow-up for a median of 37.0 months (range 21-108) 3 patients have been disease-free, 4 have had a local relapse, and 3 have had persistent disease. Seventy-seven separate serum thyroglobulin measurements have been performed; 36 on and 41 off thyroid replacement therapy. A level of thyroglobulin of less than 5 ng/ml was taken as indicative of absence of disease, and compared against combined clinical examination and 131I scanning. Overall sensitivity of thyroglobulin measurement was 36/37 (97%), and although specificity was 30/40 (75%), this rose to 30/32 (94%) if raised thyroglobulin levels noted within 3 months of 131I therapy in otherwise asymptomatic patients (n = 4) or in subjects with intact thyroid tissue (n = 4) were excluded. Concordance with clinical status was 30/31 (97%) in measurements taken on, and 31/32 (94%) in those taken off, thyroid replacement. These data indicate that thyroglobulin measurement is a sensitive and specific means of detecting residual, recurrent, and metastatic thyroid carcinoma in children.     

Differentiated thyroid carcinomas from children and adolescents express IGF-I and the IGF-I receptor (IGF-I-R). Cancers with the most intense IGF-I-R expression may be more aggressive

Adult thyroid cancers express IGF and IGF-I receptor (IGF-I-R), but the clinical impact is not clear. No previous study examined any childhood thyroid cancers that are well-differentiated and have a favorable prognosis. We used immunohistochemistry to determine IGF-I and IGF-I-R in 23 papillary thyroid cancers (PTC) and 6 follicular thyroid cancers (FTC) from children and adolescents. IGF-I was detected in 45% and IGF-I-R in 43% of cancers. IGF-I and IGF-I-R were found more often in PTC (IGF-I = 9/23, IGF-I-R = 8/19) than normal surrounding thyroid (IGF-I = 0/10, p = 0.032 and IGF-I-R = 0/10, p = 0.030). There were too few FTC to support independent statistical analysis, but IGF-I was found in 4 of 6 FTC (0/10 normal), and IGF-I-R was found in 2 of 4 FTC (0/10 normal). IGF-I-R staining was more intense in aggressive (invasive, metastatic, recurrent, or persistent) than indolent tumors (confined to the gland, p = 0.029). Over time, six tumors recurred, five of which expressed IGF-I-R. Overall recurrence risk was significantly greater for tumors that expressed IGF-I-R (p = 0.05) but only approached statistical significance (p = 0.08) when disease-free survival was determined. We conclude that differentiated thyroid cancers of children and adolescents express IGF-I and IGF-I-R. Tumors that express IGF-I-R are more likely to show aggressive clinical features (invasion beyond the capsule, metastasis, or recurrence) and persistence despite treatment.     

In situ breast carcinoma after treatment during adolescence for thyroid cancer with radioiodine

We reviewed the courses of patients treated during childhood or adolescence for thyroid cancer to estimate the frequency of, and to identify possible risk factors for, the occurrence of second malignant tumors in this population. We identified all patients treated for thyroid cancer in a cohort of 1,406 pediatric cancer patients who were diagnosed prior to 20 years of age during the period January 1, 1960 through December 31, 1988 and who were treated at Roswell Park Cancer Institute. Twelve patients were treated for thyroid cancer, of whom nine were women. In situ breast carcinoma was diagnosed 25 and 26 years after diagnosis of thyroid cancer in two of four women treated with radioiodine. No new cancers were diagnosed in the five women treated with thyroidectomy only. Two of four women treated for thyroid cancer during adolescence with radioiodine, which is concentrated in the breast as well as other organs, developed in situ breast carcinoma. Review of a large cohort of adolescent female thyroid cancer patients treated with radioiodine is necessary to provide an accurate estimate of their risk of developing breast cancer. These patients must remain under medical surveillance throughout their lifetimes to facilitate prompt diagnosis of and early intervention for new conditions, such as the occurrence of breast cancer. © 1995 Wiley-Liss, Inc.