Validity of fine needle aspiration cytology of the palpable breast lesions: A teaching hospital experience

Abstract

Background and Objective: Fine needle aspiration cytology has assumed a great importance in the pre-operative diagnosis of palpable breast lesions in several hospital and clinical settings worldwide. This study aims to audit its diagnostic utility and validity in a tertiary hospital, and to review some of the diagnostic pitfalls in interpretation of breast cytology. Materials and Methods: The study comprised of breast cytology reports and their subsequent tissue biopsy diagnoses recorded over a 5-year period from January 2008 to December 2012. Results: A total of 1162 breast cytology reports were made over the review period out of which 200 had histological confirmation. Out of the 200 cases, 109 (54.5%) were benign (C2), 20 (10.0%) cases were suspicious probably benign (C3), 27 (13.5%) cases were suspicious probably malignant (C4) and 44 (22.0%) were malignant (C5). The cytology reports were correlated with subsequent histological diagnoses. Of the 109 benign C2 reports, 99 were confirmed on tissue histology as truly benign (true negatives) and the remaining 10 cases were malignant (false negatives). Forty-three of the 44 malignant (C5) cytology reports initially made were confirmed as malignant on tissue histology (true positives). The remaining malignant (C5) cytology case was, however, revealed to be benign (false positive). The overall suspicious rate (C3 and C4) was 23.5%. The absolute sensitivity was 81.0%, specificity was 99.0%, positive predictive value (PPV) (C5) of 97.7%, negative predictive value (NPV) (C2) of 90.8%. The false positive rate (FPR), false negative rate (FNR) and suspicious rates (SR) were 1.2%, 12.0% and 23.5%, respectively. Conclusion: Fine needle aspiration cytology of the breast has recorded high absolute sensitivity and specificity in our centre with a marginally high false positive rate. It has thus continued to have relevance as an important pre-operative diagnostic tool in the management of palpable breast lesions in our hospital.