- According to the Surveillance, Epidemiology and End Results (SEER) program, new cases of thyroid cancer in people < age 20 represent 1.8% of all thyroid malignancies diagnosed in the United States. The incidence appears to be increasing.
- Compared with adults, thyroid neoplasms in the pediatric population exhibit differences in pathophysiology, clinical presentation, and long-term outcomes.
- The most common presentation for DTC in children is that of a thyroid nodule. However, papillary thyroid cancer (PTC) also frequently presents as cervical adenopathy with or without a palpable thyroid lesion, or as an incidental finding after imaging or surgery for an unrelated condition. Occasionally, the diagnosis is made only after the discovery of distant metastases.
- PTC accounts for 90% or more of all childhood cases. Follicular thyroid cancer (FTC) is uncommon while medullary thyroid cancer (MTC), poorly differentiated tumors and frankly undifferentiated (anaplastic) thyroid carcinomas are rare in young patients.
- Furthermore, therapy that may be recommended for an adult may not be appropriate for a child who is at low risk for death but at higher risk for long-term harm from over-aggressive treatment.
- The pediatric age should be limited to a patient ≤18 years of age. Establishing a uniform upper limit of age will afford an opportunity to better define the potential impact of growth on tumor behavior. From a pragmatic point of view, individual centers may transition pediatric patients to adult care anywhere between 18 and 21 years of age. Clinicians may manage the "child" under these guidelines until transition has been completed. (C)
Table 1. Recommendation Grading
|A||Strongly recommends||Good evidence that the service or intervention can improve important health outcomes|
|B||Recommends||Fair evidence that the service or intervention can improve important health outcomes|
|D||Recommends against||Expert opinion|
|E||Recommends against||Fair evidence that the service or intervention does not improve important health outcomes or that harms outweigh benefits|
|F||Strongly recommends against||Good evidence that the service or intervention does not improve important health outcomes or that harms outweigh benefits|
|I||Recommends neither for nor against||The evidence is insufficient to recommend for or against providing the service or intervention because evidence is lacking that the service or intervention improves important health outcomes, the evidence is of poor quality, or the evidence is conflicting.|
- The evaluation and treatment of thyroid nodules in children (Figure 1) should be the same as in adults with the exceptions that:
- US characteristics and clinical context should be used rather than size alone to identify nodules that warrant FNA.
- All FNA in children should be performed under US-guidance.
- Preoperative FNA of a hyperfunctioning nodule in a child is not warranted as long as the lesion is removed.
- A diffusely infiltrative form of PTC may occur in children and should be considered in a clinically suspicious gland.
- Surgery (lobectomy + isthmusectomy) is favored over repeat FNA for most nodules with indeterminate cytology. (B)
- A positive mutational test appears highly likely to be associated with malignancy. Conversely, insufficient data exist in children to rely on negative genetic studies to reliably exclude malignancy. Although molecular studies hold promise for complementing the results of FNA, particularly for nodules that yield indeterminate cytology, they have not yet been sufficiently validated in children and cannot be routinely recommended in routine clinical practice until further studies are conducted. (E)
- For patients with autoimmune thyroiditis, evaluation by an experienced thyroid ultrasonographer should be pursued in any patient with a suspicious thyroid examination (suspected nodule or significant gland asymmetry), especially if associated with palpable cervical lymphadenopathy. (B)
Treatment of Benign Nodules
- We are unable to recommend for or against the routine use of LT4 therapy for children with benign thyroid nodules. In general, the data support the efficacy of LT4 therapy to reduce the size and risk of subsequent nodule formation but there are no data to weigh this potential benefit against the potential risks of long-term suppression therapy. In patients with compressive symptoms or a history of radiation exposure the benefits of LT4 therapy may be more apparent. (I)
- Benign lesions should be followed by serial US (see Figure 1) and undergo repeat FNA if suspicious features develop or the lesion continues to grow. Lobectomy may be performed in patients with compressive symptoms, cosmetic concerns, or patient/parent preference and should be considered in all apparently benign solid thyroid nodules >4cm, those lesions demonstrating significant growth, or in the presence of other clinical concerns for malignancy. (B)
- For pediatric patients with a suppressed TSH associated with a thyroid nodule, thyroid scintigraphy should be pursued. Increased uptake within the nodule is consistent with autonomous nodular function. Surgical resection, most commonly lobectomy, is the recommended approach for most autonomous nodules in children and adolescents. (A)