Is radioiodine therapy necessary in small (≤ 1 cm) papillary and follicular thyroid carcinoma?

Abstract

49

Objectives: Papillary thyroid microcarcinomas have an excellent prognosis. According to the procedure guidelines of the German Society of Nuclear Medicine no radioiodine ablation is necessary in patients with papillary microcarcinomas in case of limited surgical resection. However, few data are available with respect to the optimal management of patients suffering from small follicular thyroid carcinomas. It was the aim to compare the risk-profile and therapeutic management of patients with small papillary and follicular thyroid carcinomas ≤ 1 cm. Methods: 1484 patients with thyroid cancer were treated at our department between 1995 and 2005. For the subgroup of 352 patients with small papillary and follicular carcinomas ≤ 1 cm a comparative correlation of multifocality, extrathyroidal growth, lymph node spread, distant metastasis and survival was performed. Patients were monitored for up to 27 years, with a mean follow-up time of 6 years. Results: A total of 332 (94%) patients had papillary and 20 (6%) follicular thyroid carcinomas ≤ 1 cm. At presentation the mean age of the 279 women and 22 men was 49 ± 13 years. High-dose radioiodine therapy was performed in 76% and 100% of patients with small papillary and follicular carcinomas, respectively. Multifocality (12% vs. 5%), extrathyroidal growth (10% vs. 0%), lymph node spread (14% vs. 5%) and distant metastasis (2% vs. 0%) were more common in patients with small papillary than follicular tumors; however, these figures did not reach statistical significance. Five patients with papillary microcarcinomas died because of extrathyroidal diseases. Conclusions: These data show that small papillary carcinomas ≤ 1 cm present with extrathyroidal growth and lymph node metastasis in a considerable number of patients. However, small follicular thyroid carcinomas ≤ 1 cm have a very low prevalence of extrathyroidal growth and lymph node metastasis. Therefore, the indication of radioiodine ablation in patients with small papillary and follicular carcinomas should be reconsidered in case of limited surgery.