Review of clinical and pathological features of 93 cases of well-differentiated thyroid carcinoma in pediatric age at the Lisbon Centre of the Portuguese Institute of Oncology between 1964 and 2006.

INTRODUCTION

Thyroid carcinoma is the most common endocrine malignancy. In childhood, thyroid carcinoma usually behaves aggressively and relapses frequently. Nevertheless, it has a favorable prognosis. Our aim is to present our experience with pediatric well-differentiated thyroid carcinoma (WDTC) treated at the Portuguese Institute of Oncology in Lisbon (L-PIO), between 1964 and 2006.

METHODS

Review of clinical files of WDTC in≤18-year-old patients selected from the databases of the Endocrinology Service of L-PIO and the South Portugal Regional Cancer Registry (SPCR).

RESULTS

93 cases of WDTC were found. Of these, 70 (75.3%) were girls. The median age was 15 years old (range 5-18) with a median follow-up time of 15.1 years (range 0.2-47.8). The most common histological diagnosis was papillary carcinoma of the classical variant (n=60, 64.5%). Initial staging showed locoregional dissemination in 27 (29.0%) patients and distant metastasis in 16 (17.2%) patients. Median age was lower in patients with distant disease than in patients with locoregional disease or with disease confined to the thyroid (P=0.007). After the initial treatment, 44 (47.3%) patients were in remission and 46 (49.5%) had persistent disease (lost follow-up in 3). Of the disease-free patients after initial treatment, 11 (25.0%) relapsed later. At the last observation, most patients (n=63, 67.7%) showed no evidence of disease.

CONCLUSION

Our study demonstrates that children with distant metastatic disease are younger than children with a less aggressive disease. However, in both groups the response to treatment is favorable and the prognosis is usually excellent.