Well-differentiated thyroid carcinoma in Hong Kong Chinese patients under 21 years of age: a 35-year experience

Background: Sporadic well-differentiated thyroid cancer is an uncommon condition in children, adolescents, and young adults. It is associated with distinct clinicopathologic features and prognosis. The present study reviews our experience in management of this condition in ethnic Chinese in Hong Kong. Study Design: A retrospective study was performed to review the clinicopathologic features and outcomes of 34 patients less than 21 years of age with well-differentiated thyroid carcinoma over a 35-year period. Median followup was 15.2 years (range 1 to 32.5 years). Results: There were 27 girls and 7 boys with a median age of 19 years (range 10 to 21 years). None had previous history of irradiation. Twenty-eight patients had papillary and six had follicular carcinomas. Operative procedures included total thyroidectomy (n = 27) and unilateral lobectomy (n = 7) with concomitant neck dissection performed in nine patients. The median tumor size was 2 cm and extrathyroidal invasion was present in 19 tumors. Adjuvant radioactive iodine treatment was administered to 18 patients after total thyroidectomy. Disease progression or recurrence rate was 24% and 27% at 5 and 10 years, respectively. The presence of lymph node metastases was associated with a higher incidence of disease recurrence. One patient with advanced local disease died from tumor bed recurrence with anaplastic transformation 18 years after the initial operation. Conclusions: Well-differentiated thyroid carcinoma is a relatively indolent tumor associated with good prognosis in young patients. Although death from this condition is rare, recurrence is frequent and longterm followup is necessary.