Stratification of intermediate-risk fine-needle aspiration biopsies

Objective: The goal of our study was to identify factors in intermediate-risk fine-needle aspiration (FNA) results that are predictive of malignancy. Design: Retrospective chart review. Setting: Head and neck oncology clinic at the London Health Sciences Centre. Methods: A database of 665 patients who had received thyroid surgery between 2001 and 2007 was created. FNA biopsy data were collected for each patient, as well as pathologic, patient, and ultrasound data. Of the 665 patients, 302 FNA biopsies were considered intermediate risk, and these data were analyzed. Main Outcome Measure: Presence of malignancy. Results: Intermediate-risk patients were significantly more likely to have a benign nodule if the width to length (W/L) ratio of their nodule was < 0.6. The relative risk was 5.64 (95% confidence interval [CI] 0.81-39.65) (p < .05). As well, patients who were in the intermediate-risk category were significantly more likely to have a malignancy if they were < 40 years old compared to those patients who were ≥ 40 years old. Conclusions: Both age and W/L ratio of a nodule can be used to help predict whether a nodule in an intermediate-risk patient is malignant. An intermediate-risk patient who has a W/L ratio < 0.6 can be treated conservatively based on the extremely low risk of malignancy (2.86%).