Accuracy of intraoperative consultation in thyroid nodules: analysis of 2,040 cases performed at Instituto Nacional de Câncer in 12 years

Introduction: The thyroid nodule is the most common clinical manifestation of thyroid diseases, and, among the procedures for its diagnosis, cytological examination is the most used. Due to the high accuracy of cytological examination, the value of intraoperative consultation (IOC) has become a matter of controversy. IOC is one of the most important and difficult procedures that a pathologist adopts, enabling the patient to be diagnosed, treated and staged in the same intervention. Objective: To evaluate the accuracy of IOC in thyroid at Instituto Nacional de Câncer (Inca). Methods: This study analyzed IOC in thyroid held in Inca from January 2001 to December 2012. The IOC diagnosis was compared with the histopathologic diagnosis, considered the gold standard, and was classified as concordant, discordant and indeterminate. From these data we calculated sensitivity, specificity and accuracy. Results: Among the 2,040 held IOCs, diagnoses were concordant in 1,770 cases (87%), discordant in 45 (2%) and indeterminate in 225 (11%). Among the 1,770 concordant cases, 1,252 (61%) were true negative, and 518 (25%), true positive. Among the 45 discordant cases, 38 (2%) were false negative, and seven (0,3%), false positive. The test sensitivity was 0.94%, specificity of 0.99% and accuracy of 0.97%. Conclusion: Our results indicate that IOC in thyroid is a highly accurate test, contributing to the surgical conduct.