Evaluating Thyroid Nodules: The Roles of Fine Needle Aspiration Cytology and Intraoperative Consultation:

Evidence-based evaluation of the risks of malignancy predicted by thyroid fine-needle aspiration biopsies

A National Cancer Institute (NCI) "Thyroid Fine-Needle Aspiration (FNA) State of the Science Conference" recently proposed standardized nomenclature and "risks of malignancies" associated with various diagnostic categories. We evaluated the evidence levels of the data used by NCI to predict malignancy risks and whether those estimates had clinical validity in our patient population.Eight hundred seventy-nine patients underwent thyroid FNA during 2006. FNA diagnoses were translated into NCI diagnostic categories, and 2-year follow-up retrospective information was obtained. Four percentages of malignancies were calculated for each diagnostic category using follow-up information from FNA, thyroidectomy, both, and all patients as denominators. 95% confidence intervals (CI) were estimated for all proportions, and results were analyzed with chi-square statistics. "Relative risk" calculations were performed using the percentage of malignancies in the entire population under study as a denominator.Most of the studies cited by the NCI provided incomplete and variable level III evidence based mainly on surgical follow-up. Among our patients, the percentages of malignancies calculated with follow-up data from all patients as the denominator were similar to the "risk estimates" proposed by the NCI, but estimates based on surgical follow-up overestimated the probability of thyroid malignancy for patients with FNA diagnosis of "benign" and "follicular lesions of undetermined significance" (FLUS). Relative risk and 95% CI calculations suggested that the NCI classification could be simplified into three categories: "benign," "FLUS + neoplasm," and "suspicious + malignant."

Diagnostic terminology and morphologic criteria for cytologic diagnosis of thyroid lesions: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine-needle Aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The two-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding diagnostic terminology/classification scheme for thyroid FNA interpretation and cytomorphologic criteria for the diagnosis of various benign and malignant thyroid lesions. (http://thyroidfna.cancer.gov/pages/info/agenda/).

Utility of intraoperative consultation touch preparations

Although intraoperative touch preparations (TPs) often are performed in conjunction with frozen sections, the comfort level of using TPs in actual practice and the effect of TP quality and cytologic experience on diagnostic accuracy have not been measured. To investigate the utility of intraoperative TPs and to compare them with that of frozen sections, five pathologists of differing levels of cytologic experience retrospectively reviewed 122 intraoperative TPs and frozen sections. Accuracy rates for individual pathologists were calculated and the accuracy using TPs was compared to that of frozen sections. TP accuracy was correlated with TP quality and cytologic experience. The mean rates of correct, incorrect, and atypical TP diagnoses were 88.5%, 4.1%, and 7.4%, respectively. The mean rates of correct, incorrect, and deferred frozen section diagnoses were 86.1%, 2.5%, and 11.9%, respectively. For the four pathologists with cytologic experience, both TP and frozen section diagnostic accuracy rates were similar; however, the pathologist who lacked cytologic experience had lower TP diagnostic accuracy. All pathologists who had cytologic experience requested a frozen section for cases with an atypical or incorrect TP diagnosis. In cases with a correct TP diagnosis a frozen section was requested 46.3% of the time. TPs of greater technical quality were associated with higher diagnostic accuracy. In conclusion, the use of performing TP and frozen section are complementary and result in increased diagnostic accuracy. For some pathologists, TPs may replace frozen sections in over 50% of cases.