To identify additional preoperative factors that could reliably be used to aid in determining the appropriate extent of thyroidectomy.
Retrospective chart review.
Tertiary care academic hospital.
Two hundred consecutively treated patients who underwent thyroid surgery after having a fine-needle aspiration biopsy procedure yielding a specimen that met the criteria for atypical cytologic features.
Main Outcome Measure
Final histopathologic diagnosis of malignant vs benign disease.
The final diagnosis was benign in 42.5% of patients and malignant in 57.5%. The presence of microcalcifications within the nodule on ultrasonography (US) was significantly associated with a higher risk of malignant disease (relative risk = 1.31, P = .04). When examined individually, age, sex, family history of thyroid malignant disease, exposure to head and neck irradiation, nodule size, rim enhancement on US, and intranodular vascularity on US were not significantly associated with an increased risk of malignant disease. Mulivariate stepwise logistic regression modeling was used to identify a model that could reliably predict a higher probability of malignant disease. The final model determined that patients with microcalcifications on US and a nodule of 2.0 cm or larger had a 74.3% risk of malignant disease vs a 47.5% risk in patients with no microcalcifications and a nodule smaller than 2.0 cm. This difference was statistically significant. When the predicted probabilities of malignant disease were compared with the observed probabilities, the goodness-of-fit test revealed no significant difference (P = .95).
Microcalcifications and nodule size can be used to risk-stratify patients with an atypical fine-needle aspiration biopsy result and aid in determining the appropriate extent of thyroidectomy.