Follicular carcinoma of the thyroid

Background. Follicular carcinomas of the thyroid are less common than papillary carcinomas of the thyroid, and the available data on prognostic factors are relatively scant. A retrospective study covering four decades was undertaken to evaluate clinical and pathologic findings with regard to their effect on prognosis. Methods. In 195 cases of follicular carcinoma treated from 1954 to 1991 age, sex, histologic type (minimally invasive vs. widely invasive), tumor size, and local, regional, and distant spread as well as the contribution of treatment to survival were evaluated in relation to prognosis. Results. Age was a significant prognostic factor: there was 100% survival of patients younger than 20 years of age at diagnosis and only one death in the 20‐39 year age group. Sex was not a significant prognostic factor, although there was a tendency to a better prognosis in females. Tumor size was significant, more than 6 cm having a poor prognosis. Blood vessel invasion influenced prognosis for the first 10 years. The presence of distant metastases was significant regarding survival. Lymph node involvement had a negative effect on the outcome. Conclusions. The factors of age, tumor size, invasion of blood vessels, and distant metastases are significant predictors of survival for patients with follicular carcinoma, whereas sex is not; regional spread needs to be evaluated further. © 1994 John Wiley & Sons, Inc.