PROGNOSTIC FACTORS IN FOLLICULAR CARCINOMA OF THE THYROID - A STUDY OF 198 CASES

Background. Prognostic parameters for papillary carcinoma of the thyro id have been defined by several groups. However, no such study has bee n reported for follicular carcinoma. Methods. We undertook a retrospec tive study of well-differentiated carcinoma of the thyroid operated at the Tata Memorial Hospital during the period 1970-1985. In our series , follicular carcinoma formed 48% of the well-differentiated carcinoma s of the thyroid. The variables age, sex, size, extrathyroidal spread, distant metastases, and lymph node metastases were evaluated. The sur vival was plotted according to the Kaplan-Meier method, and graphs com pared by log-rank test. Univariate and multivariate analyses were perf ormed. Results. Based on our experience we stratified the cases into l ow-risk and high-risk groups. The low-risk group included: age below 4 0 years, tumor size less than 5 cm, and no extrathyroidal extension or metastases. This low risk group had 100% survival at 15 years, compar ed with 40% survival for the high-risk group (P < .001). Seventy-three percent (73%) of our cases were in the high-risk group. Conclusions. Based on our findings that the majority of our patients were in the hi gh-risk group, we advocate a total or near-total thyroidectomy in trea tment of follicular carcinoma of the thyroid. There is a need to arriv e at a universally acceptable classification of risk groups in follicu lar carcinoma of the thyroid gland. (C) 1996 John Wiley & Sons, Inc.