Clinical characteristics of thyroid microcarcinomas with special reference to the prognostic factors

Lee, Junho; Lee, Sihoon; Rhee, Yumie; Ahn, Chul Woo; Cha, Bong Soo; Kim, Kyung Rae; Lee, Hyun Chul; Kim, Seung Il; Park, Cheong Soo; Lim, Sung Kil

Abstract

BACKGROUND: The incidence of thyroid microcarcinoma is increasing due to the more frequent use and improvement of ultrasonography and fine-needle aspiration biopsy. There are several prognostic factors for thyroid carcinomas. The patient's sex, age at diagnosis, muliplicity or bilaterality of tumor masses, extrathyroidal extensions, lymph node metastasis, and presence of distant metastases are considered the most important. Since the recent update of the TNM (Tumor, Node, Metastasis) staging system, the importance of lymph node metastasis is increased. There are, however, a paucity of studies on thyroid microcarcinomas in the Korean population.
METHODS
We reviewed and analyzed the records of 302 patients diagnosed with, and treated for, thyroid microcarcinomas from January through December 2004.
RESULTS
302 (50.2%) out of the 601 cases of thyroid cancers were microcarcinomas. Women comprised 275 (91.1%) of these cases. Eighty cases (26.5%) contained multiple tumor masses (> 2), and 50 (16.6%) cases exhibited bilaterality. Evaluation of the histology revealed that nearly all of the cases (300 of 302) were of the papillary type. There was only one case each of the follicular and medullary histological type. There were 85 (28.1%) cases of extrathyroidal extensions, and 91 cases (30.1%) of lymph node metastasis, but no cases of distant metastases.
CONCLUSIONS
Thyroid microcarcinomas have bad prognostic factors and appear to exist at relatively higher cancer stages. Therefore, it is important to treat them as early and as vigorously as possible with extensive surgery, radioactive iodine therapy, and thyroxine suppression.