Pediatric Thyroid Cancer Follow-up

Updated: Apr 26, 2019
  • Author: Mark E Gerber, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Follow-up

Further Outpatient Care

Postoperative therapy

  • Radioactive iodine (RAI) therapy should be administered to all children and young adults with cervical lymphadenopathy after a total thyroidectomy to reveal and treat all distant metastases in the lungs. [16]

  • Thyroid hormone replacement with levothyroxine is started in the first few days after total thyroidectomy. This replacement is withheld in patients who will receive131 I therapy.131 I is administered only to patients with extensive neck disease or distant metastases.

  • Cytomel or synthetic T3 is often used in place of levothyroxine prior to a postoperative nuclear scan or radioactive iodine (RAI) treatment. Cytomel has a shorter half-life, minimizing the period in which no suppression or replacement occurs and maximizing the uptake of radionuclide used in the scan or radioiodine therapy. A control thyroid scan is usually performed 2-3 weeks after surgery or radioiodine therapy. TSH-suppressive doses (150-200 mcg/d of T4) are thought to decrease recurrence in differentiated carcinomas. [12]

  • Thyroid carcinoma has been found to recur up to 33 years after treatment. Patients should receive close follow-up care with pulmonary function tests, chest radiography, CT scans, and thyroid function tests. [63] Thyroglobulin levels should be monitored for indications of medullary carcinoma.

  • Postoperative local external beam radiation is not recommended because of a possible carcinogenic effect in children.

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Further Inpatient Care

Serum calcium levels are measured daily for the first 2-4 postoperative days in all patients who have undergone a total or subtotal thyroidectomy. The calcium level usually drops slightly (to about 7 mg/dL) as the remaining parathyroid tissue recovers from surgical trauma. Mild hypocalcemia of this level requires treatment only if symptomatic. Mild symptoms include a positive Trousseau or Chvostek sign, mild cardiac arrhythmia, or perioral tingling. Treatment of these mild symptoms requires only oral calcium combined with vitamin D. Intravenous calcium gluconate is used for a more rapid replacement with severe arrhythmia or impending tetany.

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Inpatient & Outpatient Medications

Perioperative antibiotics are often used, and postoperative pain medications are standard, in addition to suppressive or replacement T4.

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Complications

Surgical complications include recurrent laryngeal nerve injury, hypoparathyroidism, hypothyroidism, and wound infection. [64]

  • The most common complication of a total thyroidectomy in children is parathyroid gland injury. In 6-15% of patients, parathyroid gland injury results in permanent hypoparathyroidism. [61, 28, 45]

  • Hypothyroidism in all patients after total thyroidectomy is avoided with thyroid hormone replacement.

  • Hypothyroidism occurs in 6.5-49% of patients who have undergone subtotal thyroidectomy.

  • Secondary operations are more hazardous. [60]

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Prognosis

Whereas the degree of invasion and metastases corresponds to prognosis in adults, this relationship is not seen in the pediatric population. In fact, the presence of lymph nodes does not affect the prognosis in children and adolescents. [16] The reason for this is multifactorial and can be attributed to an overwhelming majority of well-differentiated cancers, low incidence of bone metastasis, and excellent response to RAI.

  • Bone metastasis also has a low incidence in childhood thyroid cancers, occurring in less then 5% of patients.

  • Individuals with radiation-induced thyroid cancer are at an increased risk for additional cancer later in life. [38]

Pediatric patients have higher local and distant recurrence rates than adults, but they tend to respond rapidly to therapy. The prognosis is excellent in children, with mortality rates of less than 10%.

The overall 20-year survival rate is 92-100%.

Some studies report young age as the major determinant of recurrence in pediatric-differentiated thyroid carcinoma, which suggests a difference in tumor biology.

Rearrangements in the ret protooncogene have been observed in those exposed to radiation, with a reported ret rearrangement rate between 50 and 70%. [27] Williams et al studied Chernobyl-induced thyroid tumor behavior and found that thyroid tumors associated with the ret and PTC3 oncogenes were more aggressive, faster growing, and less differentiated. [24] Thyroid tumors with the ret/PTC1 oncogene had more benign characteristics and were slower growing.

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