Pediatric Thyroid Cancer Highest Among Teenage Girls

Thyroid cancer is the third most common tumor malignancy in children. This pediatric cancer shares several characteristics with adult thyroid cancer patients including common subtypes that include papillary, follicular and medullary; and a female to male ratio is approximately 6:1, among others.

While the long-term survival of pediatric thyroid cancer is purportedly excellent, there have been few large studies identifying clinical outcomes of this childhood malignancy. Most studies have been comprised of single-institution reviews. Multiple institutional studies have occurred but efforts to create a larger database may be limited by institutional or regional bias. The sample size limitations in these studies, coupled with the need for long-term follow-up of a disease with a slow rate of recidivism, have resulted in difficulties in assessing positive and negative predictive outcomes for treatment.

Two otolaryngologist—head and neck surgeons set out to identify such outcome variables through following large numbers of patients over a long period of time should be analyzed which avoid institutional and regional bias. They examined a large national database over a 12-year period in an effort to better understand long-term clinical outcomes of this indolent, although occasionally fatal, disease on a national level in the pediatric population. The length of this study avoided inherent biases in this type of research.

The authors of “Population-based Outcomes for Pediatric Thyroid Carcinoma,” are Nina L. Shapiro MD, Division of Head and Neck Surgery, UCLA School of Medicine, Los Angeles, CA; and Neil Bhattacharyya MD, at the Division of Otolaryngology, Brigham and Women’s Hospital, and the Department of Otology and Laryngology, Harvard Medical School, Cambridge, MA. Their findings are to be presented at the 19th Annual American Society of Pediatric Otolaryngology http://www.aspo.us meeting being held May 2-3, 2004, at the JW Marriott Desert Ridge Resort & Spa in Phoenix, AZ.

Methodology: The Surveillance, Epidemiology, and End Results (SEER) database (1988-2000) was reviewed, extracting all pediatric patients with thyroid carcinoma according to the following criteria: (1) Age at diagnosis ranging from birth to 18 years; (2) Primary extension of malignant thyroid tumor; (3) Well-differentiated thyroid carcinoma (papillary or follicular) and (4) Year of diagnosis between 1988 and 2000. Patients with alternative tumor types such as anaplastic or medullary carcinoma were excluded. Clinical and tumor-specific data extracted from the database included age at diagnosis, gender, tumor histology, tumor size, extent of primary site disease, extent of nodal disease, treatment with surgery and/or radioactive iodine, and survival statistics.

Data were tabulated and imported into SPSS version 10.0. From the of disease variables, the extent of primary site disease was staged as previously reported. Nodal disease was recorded as presence or absence of cervical nodes at the time of initial diagnosis. The extent of primary site surgical therapy was classified as biopsy only, lobectomy, subtotal thyroidectomy, or total thyroidectomy.

Results: The researchers identified 566 pediatric thyroid carcinomas in the 12-year period. The mean age at presentation was 16.0 years, with 84 percent of patients female. Tumor types consisted of 378 (66.8 percent) papillary carcinomas, 137 (24.2 percent) papillary carcinomas with follicular variant, and 51 (9.0 percent) follicular carcinomas. Overall, the average tumor size at presentation was 2.6 centimeters. With regard to primary disease site, the majority of patients (74.2 percent) had intrathyroidal disease alone. A small group had minor local extension (12.5 percent), and few had major or extravisceral extension (5.4 percent). Positive nodal disease in the neck was present in 37.1 percent of patients at initial diagnosis. The vast majority of patients were treated with total thyroidectomy (72.8 percent) followed by subtotal thyroidectomy (13.4 percent) followed by simple lobectomy (7.2 percent). Radioactive iodine treatment was administered to 51.4 percent of patients.