An estimate of risk of malignancy for a benign diagnosis in thyroid fine-needle aspirates

Abstract

Background: The risk of malignancy for a benign diagnosis in a thyroid fine-needle aspiration is controversial because of lack of histologic follow-up.

Methods: The author reviewed the results of all thyroid aspirations with surgical resection performed during the past 13 years at Baptist Hospital of Miami and Homestead Hospital, Homestead, Florida, combined these procedures with those in the literature, and correlated risk of malignancy with percentage of biopsies performed.

Results: A total of 7089 aspirations and 1331 resections were performed. In the literature, the percentage of all benign cases that underwent resection ranged from 3% to 41%. Risk of malignancy decreased with an increased percentage of resections. The risk of malignancy for series with <8% of all benign aspirates resected was significantly higher than the risk for series with >or=8% of cases biopsied (15.1% vs 5.9%, P = .02). Logarithmic and linear estimates of risk of malignancy if 100% of cases were biopsied were 3% and 2.5%.

Conclusions: The best estimate of the risk of malignancy for a benign diagnosis in a thyroid fine-needle aspiration is 2.5%-3%. This level of risk is affected by the percentage of benign cases that are resected.

(c) 2010 American Cancer Society.