Differentiated thyroid cancer

Objective: The retrospective analysis of the case files of children with differentiated thyroid carcinoma (DTC) was performed to define the disease by its presentation, clinical course and outcome of radioiodine therapy.Methods: Between 1967 to October 2002,1754 patients with thyroid cancer were treated in the Dept of Neuclear Medicine, AIIMS, out of which 122 (7%) were ≶ 20 years of age (71 girls and 51 boys). The mean age was 15.8 ± 3.6 years and the mean duration of follow-up was 90 ± 59.3 months. Mean tumor size was 4.4 cm. Histologically, 85% of the patients had papillary and rest follicular carcinoma. Cervical lymph node involvement was seen in 64%, and distant metastases, mainly pulmonary, in 23% of the patients. The presentation of the disease was very aggressive in the first decade of life with male preponderance. All but one patient in this age group had nodal and/or distant metastases; in 83.3% the disease had spread to the lymph nodes and 67% had metastases to the lungs. The post-surgery 48-hour mean radioiodine neck uptake was 10.5 ± 7.6%.Results: 94% of the residual thyroid, 88% of nodal metastases and 71% of pulmonary metastases were ablated requiring mean cumulative doses of 2.8 ± 2.7 GBq, 4.5 ± 2.7 GBq and 10.4 ± 7.9 GBq of131I, respectively. Average number of doses required for remnant, nodal and pulmonary metastases ablation were 1.3, 2.2 and 3.3, respectively. 80% of the patients with only remnant thyroid tissue and 50% with cervical lymph node metastases got ablated with a single dose of131I. Overall, 87% patients were currently free of disease. While, nine patients had nodal recurrence between surgery and radioiodine treatment, no recurrence was observed thereafter and 3 disease related deaths producing overall mortality of 2.5% (all in children ≶10 years of age) were seen in the mean follow-up of 7.5 years.Conclusion: Differentiated thyroid cancer in children and adolescents is rare but aggressive. The biological behavior differs from that in adults and is related to the age. Younger the age (≶10 years), more aggressive and widespread is the disease with male preponderance and high mortality. The Post-surgical radioiodine ablation/therapy is an important and effective adjuvant in the management of DTC in children and adolescents and even though they present with advance disease, long-term survival and overall prognosis is good.