Evaluation of indeterminate thyroid cytology by second-opinion diagnosis or repeat fine-needle aspiration: which is the best approach?

OBJECTIVE: This study investigated a published series evaluating the role of second-opinion diagnosis (SOD) or repeat fine-needle aspiration cytology (RFNA) for indeterminate thyroid aspirates. STUDY DESIGN: Twenty-three studies were selected and the following parameters were analyzed: disagreement between SOD or RFNA and the original diagnosis (OD), reclassification of OD according to the Bethesda system for reporting thyroid cytopathology, the rate of definitive diagnosis and the diagnostic performance of SOD and RFNA. RESULTS: 7,154 thyroid FNAs were retrieved from 9 studies that investigated the role of SOD, including 1,048 (14.6%) cases originally reported as indeterminate. The 14 studies that analyzed the role of thyroid RFNA comprised 67,581 FNAs and included 7,246 (10.7%) indeterminate cases. A definitive diagnosis was achieved by SOD in 450 cases (42.9%) and RFNA in 1,645 cases (57.2%, p=0.0001). Based on cases with histological follow-up, SOD demonstrated significantly higher rates of positive predictive value and accuracy than RFNA (55.8 vs. 37.7%, p=0.0001; 67.4 vs. 56.0%, p=0.0034, respectively). CONCLUSIONS: Both SOD and RFNA demonstrated an improvement in the diagnosis of initially indeterminate thyroid FNAs. RFNA achieved a definitive diagnosis for the majority of indeterminate cases. Regarding histological follow-up, SOD was shown to be more accurate than RFNA.