Clinical presentations and predictive variables of thyroid microcarcinoma with distant metastasis

Background. Thyroid microcarcinoma is not an uncommon disorder. The purpose of this study is to analyze the clinical presentation and predictive factors for patients with thyroid microcarcinomas who have distant metastases. Methods. We retrospectively reviewed and analyzed the clinical variables of 97 patients with thyroid microcarcinoma during the period from 1977 to 1995. The patients were divided into 2 groups representing patients with and without distant metastases. These data were analyzed by the Mann-Whitney U, χ² and Fisher's exact tests. Results. Of the 97 patients with thyroid microcarcinomas, there were 6 (6.2%) cases (F/M = 5/1) with distant metastases. Among them, 3 cases were papillary carcinomas and 2 cases were follicular carcinomas. The parameters: age at diagnosis (P = 0.0137), one month postoperative serum thyroglobulin (Tg) level (P = 0.0215), cervical lymph node metastasis (P = 0.0097), and follicular cell type (P = 0.0079), were determined to be factors predictive for distant metastases by statistical analysis. There were no statistical differences between gender (P = 0.5781), postoperative ¹³¹I uptake (P = 0.1238), tumor size (P = 0.0571), preoperative thyroid function (P = 0.4425), fine-needle aspiration cytology (FNAC) (P = 0.9723), preoperative thyroid scan (P = 0.9765), and operative methods (P = 0.1060) between these two groups. Conclusions. Most thyroid microcarcinomas presented with relatively benign clinical courses, but patients with adverse predictive factors need more aggressive interventions to improve outcome.