Sunday, April 10, 2011

Pediatric Thyroid Cancer Treatment Overview

    Treatment for thyroid malignancy is primarily surgical:  Because of the unusual combination of an excellent prognosis and an advanced-stage disease presentation, the initial extent of surgery is controversial. Some recommend that the initial surgical approach should be conservative, while others advocate aggressive management with total thyroidectomy and radioactive iodine (RAI) for all patients. The relative infrequency of thyroid malignancy makes this controversy difficult to resolve.
  • Thyroid lobectomy is the initial procedure of choice for most solitary thyroid lesions. This procedure adequately removes the pathologic region but spares enough thyroid tissue to maintain a euthyroid state. The thyroid lobule should be sent immediately for frozen section. If the frozen section confirms carcinoma, total or subtotal thyroidectomy can be completed. If the initial frozen section is indeterminate, one should wait for the final report. If the final pathology finding reveals carcinoma, then a total or subtotal thyroidectomy can be performed at a later date.
  • The need for total versus near-total or subtotal thyroidectomy is controversial. Proponents for near-total or subtotal thyroidectomy believe that these procedures decrease the incidence of complications such as recurrent nerve injury and parathyroid devascularization, although the need to identify and preserve these structures remains.  A near-total thyroidectomy with radical lobectomy on the side of the primary lesion and subtotal removal of the contralateral lobe is recommended if the lesion is proven to be or suggestive of carcinoma.
  • Although total thyroidectomy has not been proven to decrease recurrence, supporters of this method argue that remaining thyroid tissue may interfere with the use of radioactive iodine (RAI) in the postoperative diagnostic scanning and in the treatment of microscopic regional and distant disease. Residual thyroid tissue also provides a source of thyroglobulin that may postoperatively diminish the specificity of the test as a tumor marker.

  • Medullary Carcinoma: Total thyroidectomy and central neck dissection are indicated for biopsy-proven medullary carcinoma. Prophylactic total thyroidectomy may be indicated in children with a family history of multiple endocrine neoplasia (MEN) syndrome. Genetic screening is now possible for the MEN2 gene, and prophylactic surgery may be performed in patients as young as 5 years to prevent the occurrence of C-cell hyperplasia or carcinoma.

Neck dissection: Selective ipsilateral neck dissection in pediatric thyroid surgery is indicated for proven or suspected regional lymph node metastasis. During the dissection, lymph nodes in the paratracheal region, tracheoesophageal groove, and lateral areas can be inspected. Suspicious nodes are excised.

  • Formal neck dissection has not been shown to improve outcome and has an increased risk of minor surgical complications. The authors advocate the use of total thyroidectomy with selective neck dissection for the treatment of pathologically confirmed thyroid carcinoma.

    In-patient Post Surgical 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.

    Long Term Medications:  Postoperative suppression of TSH with thyroid hormone may decrease recurrence and is more effective in papillary and papillary-follicular carcinomas. 
  • Radioactive Iodine Therapy: Radioactive therapy with iodine 131  is indicated to ablate residual normal thyroid and to treat functioning metastases in differentiated thyroid tumors. Because pediatric patients are few and the prognosis is generally excellent, 131I is usually recommended only for patients with extensive unresectable cervical nodal involvement, invasion of vital structures, or distant metastases. Very few instances of solid tumors or leukemia associated with 131I treatment have been reported.

    Final Thoughts: Surgical complications include recurrent laryngeal nerve injury, hypoparathyroidism, hypothyroidism, and wound infection.
    • 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.
    • 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.

    AUTHOR: Mark E Gerber, MD, FACS, FAAP  Clinical Assistant Professor of Otolaryngology, University of Chicago, Pritzker School of Medicine; Section Head, Pediatric Otolaryngology-Head and Neck Surgery, NorthShore University HealthSystem 

    CO-AUTHOR: Brian Kip Reilly, MD  Assistant Professor of Otolaryngology and Pediatrics, Department of Otolaryngology, Children's National Medical Center, George Washington University School of Medicine

No comments:

Post a Comment