Follicular Thyroid Carcinomas with Lung Metastases: A 23-Year Retrospective Study

Abstract

Limited clinical information is specified in the presentations, results of treatment and prognostic factors of follicular thyroid carcinoma with lung metastases. In order to better characterize the information, we retrospectively analyzed the data of 2,003 thyroid cancer patients who received treatment and follow-up at the Chang Gung Memorial Hospital during the period from January 1979 to December 2002. There were 1,516 cases of papillary and 272 cases of follicular thyroid carcinomas. In the study, lung metastases of the follicular thyroid carcinomas were defined as post-operative or follow-up chest X-ray, diagnostic or therapeutic ¹³¹I scan with positive finding of lung metastases. Serum thyroglobulin (Tg) levels under thyroxine treatment of patients with lung metastases had to be over 1.5 ng/mL. Of the follicular thyroid carcinomas, there were 70 (25.7%) with lung metastases including 50 females (mean age 54.1 ± 12.6 years old) and 20 males (mean age 59.4 ± 12.0 years old). Of the 70 patients, there were 53 patients (75.7%) who presented with lung metastases at the time of diagnosis. Of the 70 patients of follicular thyroid carcinoma with lung metastases, 30 patients (42.9%) died at the end of the follow-up, and only 4 patients improved to disease free status. The 5, 10, 15, and 20 year survival rates in these patients were 68.5%, 54.0%, 41.6%, 27.7%, respectively. Age, post-operative Tg level and tumor size are important prognostic factors which are demonstrated to be significantly different statistically between lung metastases group and the group of the patients without distant metastasis. Otherwise, only the tumor size and accumulative dose of ¹³¹I therapy demonstrate a significant difference between survival and mortality groups. Seventeen of the 70 patients developed lung metastases during the follow-up period. Mean period between diagnosis and recurrence of these patients was 3.6 ± 0.9 years. Over 75% of follicular thyroid carcinoma with lung metastases was diagnosed at the time of presentation. Forty percent (28/70 cases) of the follicular thyroid carcinoma with lung metastases had history of thyroid surgery in this study. If lung metastases are diagnosed in follicular thyroid carcinoma, it will be followed by a poor prognosis. Older patients, higher postoperative Tg, and larger tumor size in follicular thyroid carcinoma need aggressive postoperative treatment.