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

Paediatric differentiated thyroid carcinoma: a UK National Clinical Practice Consensus Guideline

This guideline is written as a reference document for clinicians presented with the challenge of managing paediatric patients with differentiated thyroid carcinoma up to the age of 19 years. Care of paediatric patients with differentiated thyroid carcinoma differs in key aspects from that of adults, and there have been several recent developments in the care pathways for this condition; this guideline has sought to identify and attend to these areas. It addresses the presentation, clinical assessment, diagnosis, management (both surgical and medical), genetic counselling, follow-up and prognosis of affected patients. The guideline development group formed of a multi-disciplinary panel of sub-speciality experts carried out a systematic primary literature review and Delphi Consensus exercise. The guideline was developed in accordance with The Appraisal of Guidelines Research and Evaluation Instrument II criteria, with input from stakeholders including charities and patient groups. Based on scientific evidence and expert opinion, 58 recommendations have been collected to produce a clear, pragmatic set of management guidelines. It is intended as an evidence base for future optimal management and to improve the quality of clinical care of paediatric patients with differentiated thyroid carcinoma.

[Follow-up of children and young adults with differentiated thyroid cancer treated with radioiodine]

This is a retrospective study carried out in a group of 30 patients with differentiated thyroid cancer (age at diagnosis equal to or less than twenty years old). The aim of the study is to evaluate outcome after 131I therapy. Patients were classified into three groups on the basis of initial surgery, pathology and scintigraphic results: group I (thyroid extent), group II (locoregional extent), and group III (distant metastatic disease). Clinical parameters, 131I scans, serum thyroglobulin determinations and 131I therapeutic administered doses were evaluated in the follow-up. Some other complementary techniques such as chest X-ray and pulmonary function tests are also described. Scintigraphic absence of thyroid tissue has been observed in 83% of the cases; high thyroglobulin level is still detectable in 34% of the patients as a single evidence of disease, and 21% remain without any abnormal clinical, scintigraphic or analytical findings. Total doses administered have increased in groups I, II and III respectively, and have also been inversely proportional to the extension of lymph node surgery. At present, all the patients are alive and in good general condition. According to the results obtained, we conclude that children and young adults with DTC should undergo periodical 131I therapeutic doses in case of positive scans (once total thyroidectomy has been realized, with or without lymph node resection depending on the extension of disease). In our experience, the use of radioiodine is effective and safe in the follow-up of children and youngs with DTC.

Current controversies in the management of pediatric patients with well-differentiated nonmedullary thyroid cancer: a review

Current treatment strategies for pediatric patients with nonmedullary, well-differentiated thyroid carcinoma (WDTC) are derived from single-institution clinical cohorts, reports of extensive personal experience, and extrapolation of several common therapeutic practices for this tumor in adults. Because pediatric WDTC is an uncommon malignancy, the issues of its optimal initial and subsequent long-term treatment and follow-up remain controversial. Pediatric patients with WDTC can be divided into two groups: children younger than 10 years of age and teenagers/adolescents between 10 and 18 years of age because these groups have different recurrence and mortality rates. We hereby present our views and interpret them in the light of the pertinent literature. Our recommendations on treatment strategies are more relevant for younger children. After midpuberty, optimal treatment is adequately addressed in the relevant literature on adults. For the majority of patients, total/near-total thyroidectomy is currently recommended as the standard initial therapy for WDTC. This is commonly followed by administration of radioiodine (RAI; (131)I) therapy to destroy residual normal thyroid tissue (remnant). Routine (131)I remnant ablation has been shown to: (1). decrease the risk of local recurrences, (2) increase the sensitivity of subsequent diagnostic RAI whole-body scanning (WBS), and (3) render serum thyroglobulin (Tg) a highly sensitive marker for recurrent/residual disease during long-term follow-up. We recognize that the above practices are not universally adhered to in children and adolescents, because the risk stratification and intensity of applied therapeutic measures are influenced by institutional traditions and personal experience. In our view, aggressive initial management, followed by evaluations at regular intervals after thyroidectomy and (131)I remnant ablation, in conjunction with long-term thyroid hormone suppressive therapy (THST), result in decreased recurrence rates in pediatric patients with WDTC. Follow-up examinations should include a diagnostic RAI ((131)I or (123)I) WBS and measurement of serum Tg, both performed under conditions of TSH stimulation, as well as neck ultrasonography (US). Our strategy is corroborated by data from retrospective clinical cohort studies. In this malignancy, no evidence of disease (NED) status can be defined as the combination of a negative diagnostic WBS and the presence of undetectable or low serum Tg levels, both tested under TSH stimulation. These findings should be accompanied by the absence of anatomically definable disease by standard imaging modalities, e.g., neck US or chest computed tomography (CT). Although the long-term survival rates are good overall in this disease, selected patients may require further surgery or (131)I therapy for the eradication or clinical control of metastases. Finally, and importantly, because the duration of follow-up is lifelong, the care of children with prior diagnosis of WDTC should be transferred to an adult endocrinologist after they reach adulthood, even if they have achieved NED status by that time.

The role of 123I-diagnostic imaging in the follow-up of patients with differentiated thyroid carcinoma as compared to 131I-scanning: avoidance of negative therapeutic uptake due to stunning

OBJECTIVE

Some patients with relapsed differentiated thyroid cancer may show rising thyroglobulin (Tg) levels despite a lack of 131I uptake on routine whole body imaging. A significant proportion of these patients, after therapy doses of 131I, may demonstrate positive 131I uptake with a subsequent fall in serum Tg, implying a therapeutic effect. Attempts to identify such patients by increasing the dose of the diagnostic 131I tracer may lead to inhibition of subsequent uptake after the therapy dose, an effect referred to as 'stunning' and associated with a reduction in therapeutic effect. 123I is a short half-life gamma-emitter, thought to be unlikely to cause stunning, which may thus be more suitable than 131I for diagnostic imaging of thyroid cancer.

DESIGN AND PATIENTS

The efficacy of the 123I radionuclide was determined in a longitudinal study of 12 patients who were selected only because they showed elevated serum Tg and a negative diagnostic 131I whole body study prior to therapy with 131I.

RESULTS

There was almost complete concordance in uptake between 123I diagnostic imaging and the final scans carried out after 131I therapy (hereafter known as therapy studies) in 11 out of 12 patients at their first evaluation, in each of four patients receiving 123I at their second evaluation and in a single patient receiving 123I at a third evaluation. One patient had a positive 123I study but a negative 131I therapy study: following therapy Tg declined from 5.5 pg/l to undetectable levels, implying a therapeutic effect, and suggesting that the negative uptake was not the result of stunning. Two negative diagnostic 123I studies were followed by negative therapy studies, and thus there were no false negatives. 123I correctly identified disease in the nine patients with metastases in the lungs, mediastinum and bone at the first evaluation, in all four patients at the second evaluation and in the single patient at the third evaluation. At the end of the study, patients had received up to three 131I therapy doses, Tg had risen in four patients, fallen in eight and become undetectable in one patient.

CONCLUSIONS

123I is highly sensitive in diagnosing local recurrence and metastatic disease, and produces scintigraphic images which concord well with uptake following 131I therapy. It is proposed that 123I imaging, in combination with serum Tg measurements, should replace 131I tracer imaging as an indicator of the potential efficacy of 131I therapy. Stunning, with its detrimental effects on 131I therapy, may thus be avoided. The possibility of false negative images due to the stunning phenomenon must always be borne in mind if there is a discrepancy between positive 131I imaging studies and a surprisingly negative subsequent 131I therapy scan.

Cancer of the thyroid gland in infants and children

Carcinoma of the thyroid gland is unusual in children and represents only about 3% of pediatric malignancies. Surgical management is the principal method of treatment, but there is considerable controversy regarding exactly how much of the thyroid gland should be removed for adequate treatment. There also is controversy regarding the use of fine-needle aspiration (FNA) in the evaluation of potentially neoplastic thyroid lesions. In this report, the pertinent literature is reviewed regarding these issues. Moreover, this report will discuss recent discoveries that have elucidated some of the molecular biological events responsible for the development of thyroid cancer.

Carcinoma of the thyroid in children: a 25-year experience

Over the past 25 years, 23 children with carcinoma of the thyroid have been treated at the Christie Hospital, Manchester. Twenty-one cases were well-differentiated carcinoma, and two were medullary carcinoma. They were all treated by resection, 14 with total thyroidectomy and 9 with lobectomy or subtotal thyroidectomy. Sixteen children also had surgery for nodal disease. Two children presented with lung metastases. Sixteen children received post-operative radiotherapy (4 external beam, 12 131I). Median follow-up of 67 months (range 7-233), was the same for the 21 well-differentiated carcinomas and the whole group including the two medullary carcinomas. All 21 children with well-differentiated carcinomas are alive with no evidence of progressive disease. Two relapsed after total thyroidectomy, but both were salvaged, one with external beam radiotherapy, one with 131I. One child with medullary carcinoma died with progressive disease after 43 months, the other is alive, but with slowly progressive disease 145 months after diagnosis. Ten of 14 children experienced post-operative hypocalcaemia following total thyroidectomy, in 7 cases it persisted long-term. 131I and external beam radiotherapy were both well tolerated. The long-term results of treatment of well-differentiated carcinoma of the thyroid are excellent, but there remains disagreement over the extent of treatment required. Some authors believe the condition is multifocal and requires total thyroidectomy, others argue that lobectomy or subtotal thyroidectomy avoids the possible post-operative complications of total thyroidectomy and gives equal long-term cure rates. We agree with the latter view. Although a small series cannot be conclusive, we feel that our results are consistent with this. We also believe, that for children, radiotherapy can be reserved for relapse only, as long as regular follow-up is available.

Primary thyroid carcinoma in children: a retrospective study of 20 patients

A total of 20 children (median age 11 years) were treated for primary thyroid carcinoma from 1976 to 1990. Papillary adenocarcinoma was diagnosed in 19 and follicular in one case. Nineteen of 20 patients were considered amenable to surgery, which consisted of total thyroidectomy in 14 and partial thyroidectomy in 5. Only one patient with extensive perithyroid soft tissue infiltration was treated with external beam radiotherapy. Monolateral or bilateral cervical nodal dissection was performed in eight and six children, respectively; in nine cases without clinical evidence of metastatic nodes. Pathological examination showed that tumor extent was greater than that clinically assessed: Multiple tumor foci within the thyroid were assessed in 8/19, unilateral positive nodes in 8, and bilateral in 6, and soft tissue infiltration in 7. Subsequently 10 patients received thyroid-stimulating hormone (TSH) suppressive hormonotherapy. Relapses occurred in 7/20 at 2-48 months (median 18) from primary treatment: Four in cervical nodes, two in cervical nodes and lungs, and one in lungs. These seven patients were salvaged with node dissection and radioiodine therapy for lung metastases. All the 20 children are alive and disease-free after a median follow-up of longer than 10 years. The incidence of relapse was greater in the group of patients not given TSH-suppressive hormonotherapy. Total thyroidectomy produced permanent hypoparathyroidism in 5/14 (36%). Thyroid carcinoma in children of this series frequently presented with multiple tumor foci within the thyroid and cervical node metastases. Prognosis was favourable even after relapse and was not related to the extent of surgical treatment. Limited surgery and suppressive hormonotherapy may be adequate therapy for thyroid carcinoma in children.