Concordance and Discordance Between BI-RADS and The IAC Yokohama System for Reporting Breast FNAB Cytopathology for Diagnosis of Palpable Breast Lesions: An Institutional Study

Abstract Background: Breast cancer is one of the most prevalent cancers in women worldwide. Early diagnosis of breast lesions is indispensable, as this significantly decreases morbidity and mortality. Triple assessment (physical examination, radiology, and pathological examination-FNAC/core biopsy) is widely used for accurately diagnosing palpable breast lesions. Radiological discordancy poses challenges in precise pathological reporting and limits clinicians’ decision making with regards to pre-operative and post-operative patient management. Aim: To evaluate concordance & discordance rates between BI-RADS (Breast Imaging-Reporting and Data System) and the IAC Yokohama system for reporting breast FNAB cytopathology for diagnosis of palpable breast lesions. Methods: This retrospective observational study conducted over a period of 1 year (01/01/2023-31/12/2023); included 116 cases with both BI-RADS and cytopathological diagnosis available. Diagnosis of all cases was confirmed by histopathology. Further concordance and discordance rates were tabulated. Results: Data retrieved from 116 cases-age wise distribution of cases, mean size, laterality, quadrants involved, number of lumps and presenting complaints with duration. USG features included echogenicity, margins, type of lesion and BI-RADS score. Correlation of BI-RADS with cytopathology included concordant malignant (83.33%) and benign (98.8%) cases, discordant malignant (16.67%) and benign (1.2%) cases, sensitivity (83.33%), specificity (98.8%), positive predictive value (96.2%), negative predictive value (94.4%), accuracy (94.8%), concordance (94.8%) and discordance rate (5.2%) were tabulated. 6/116 cases were discordant. Conclusion: Detailed understanding with a robust multidisciplinary approach is required for definitive diagnosis, effective implementation of ameliorative strategies and long-term follow-up of patients. The purpose of FNAC is to confirm the diagnosis preoperatively in conjunct with BI-RADS, as both screening tools have their own limitations; and thus, avoid unnecessary surgery in specific benign conditions.