‘Suspicious for Papillary Thyroid Carcinoma' before and after The Bethesda System for Reporting Thyroid Cytopathology: Impact of Standardized Terminology

Abstract

Background: The high-risk ‘suspicious for papillary thyroid carcinoma' (SPTC) is a clinically relevant diagnosis in the cytological interpretation of thyroid aspirates. While The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has provided invaluable terminology standardization, a performance comparison for this diagnostic category has not been performed. Therefore, this study evaluates the SPTC diagnosis before and after the introduction of TBSRTC in a large meta-analysis and at a single institution. Materials and Methods: The meta-analysis analyzed publications of SPTC or similar diagnoses before and after the introduction of TBSRTC. Similarly our own institutional experience was analyzed for the 8 years surrounding the introduction of TBSRTC. A correlation of the cytopathology and surgical pathology diagnoses was performed. Results: The introduction of TBSRTC coincided with a significant decrease in the fraction of cases called SPTC in the meta-analysis (4.5-3.1%, p < 0.00001) and in the institutional review (1.7-0.9%, p = 0.005). Meanwhile, the malignancy risk for those cases increased significantly in the meta-analysis from 62.5 to 80.5% (p < 0.00001) and trended upwards in the institutional review from 69 to 79% (p = 0.4). The follow-up rate was similar in both time periods in the meta-analysis and the institutional review. Conclusions: The introduction of TBSRTC coincided with a decrease in the fraction of cases called SPTC and an increase in the malignancy risk associated with that diagnosis.