A Different Perspective on Evaluating the Malignancy Rate of the Non-Diagnostic Category of the Bethesda System for Reporting Thyroid Cytopathology: A Single Institute Experience and Review of the Literature

Abstract

ObjectiveTo determine the malignancy rate in the non-diagnostic (ND) category of the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based on a different approach in relation to histopathology diagnoses.Study DesignAll ND fine needle aspirations (FNAs) that were performed under ultrasound guidance by an interventional radiologist with rapid on-site evaluation were included in the study. Slides were reevaluated to identify the cause of inadequacy as “qualitative” or “quantitative.” The malignancy rate of the ND category was assessed. Nodule/patient characteristics were compared between benign and malignant cases within the study cohort.ResultsThe study cohort consisted of 192 ND aspirations. Overall there were 156 (81.3%) women and 36 (18.7%) men with a mean age of 50.6 years (range 24–82 years). The malignancy rate was 4.7%. None of the nodules (size, consistency, and number) or patient characteristics (gender and age) were found to be predictive of malignancy.ConclusionThe malignancy rate of the ND category was high when compared to BSRTC predictions, but at the low end of the reported malignancy rates in the literature. Our results revealed that cyto-histopathologic correlation and method of malignancy rate estimation could have an effect on a wide range of reported malignancy rates. Furthermore, patient/nodule dependent factors were not statistically found to be predictive of malignancy.

The impact of rapid on‐site evaluation on thyroid fine‐needle aspiration biopsy: A 2‐year cancer center institutional experience

“…As a matter of fact, regardless of the somewhat high rate of AUS/FLUS, the AUS/FLUS:malignant ratio in the current study did not exceed 3 (417/149 = 2.8), thereby supporting the quality of our practice . Our reported ROMs for the ND and AUS/FLUS categories were greater than those proposed by the updated TBSRTC, but still comparable to previously reported experiences regarding what can be affected directly and biased by the selection of clinically suspicious nodules for surgery and a higher incidence of malignancies in a cancer center environment . The ROMs for the malignant category reported herein (92.6% in the non‐ROSE group and 93.8% in the ROSE group) were lower than those estimated by the first edition of TBSRTC (range, 97%‐99%) .…”

Malignancy Rates of Thyroid Cytology: Cyst Fluid Benign or Non-Diagnostic?

“…The rate of non-diagnostic specimens was found to be 22.6% in our study. This is higher than what has been reported in the literature [ 6 – 15 , 19 , 20 , 22 ]. Reasons for this difference might include that the daily number of patients per physician was higher in our hospital, physicians who perform aspirations in our hospital were allowed an average of four minutes for each patient and the aspirations were performed using a single needle.…”

“…In our study, the total number of benign and non-diagnostic categories accounted for 90.9% of cases. In the literature the rate has been reported to range from 59% to 84% [ 6 – 20 , 23 ]. Bongiovanni et al found in their meta-analysis that this rate was about 72% [ 22 ].…”

The Bethesda System for Reporting Thyroid Cytopathology: A Cytohistological Study

“…Nondiagnostic (ND) thyroid FNA result remains a major constraint in arriving at a definitive diagnosis and is the most common cause of false negative reports [4]. It is difficult to assess the risk of malignancy for the ND category because only a small subset of ND nodules undergoes resection.…”

“…Gunes et al stated that the clinical expertise of the person performing the FNA, ultrasound guidance, and rapid on-site evaluation for specimen adequacy were not uniform between studies which contributes to the wide range of malignancy rate. All these determinants make the comparison between studies cumbersome and should be taken into consideration while labelling a specimen as nondiagnostic and assessing the risk of malignancy [4]. Some of the studies stated that the operator experience and the number of passes made during FNA correlate with the nondiagnostic result [7,8].…”