IAC standardized reporting of breast fine-needle aspiration cytology, Yokohama 2016: A critical appraisal over a 2 year period.

Background: Breast cytology is a significant component of the "Triple approach" for pre-operative diagnosis of breast lumps, the other two being clinical assessment and radiological imaging. The role of Fine needle aspiration cytology (FNAC) as a first line investigation in diagnosing breast lesions is well documented, however histopathology is the gold standard. Cyto-histopathological correlation is of great relevance and also increases precision.AIMS \& OBJECTIVES:The present study was conducted with the aim to categorize breast lesions according to the latest standardized reporting system proposed by International academy of cytologists (IAC) in 2016. Evaluation of diagnostic accuracy, sensitivity and specificity of FNAC in diagnosing breast lesions and cyto-histopathological correlation was planned.

Materials And Methods: All FNAs of breast lesions over a period of 2 years were included in the study. The cases were grouped into five standardized categories proposed by the International academy of cytology: Category I (Insufficient material), Category II (Benign), Category III (Atypical, probably benign), Category IV (Suspicious, probably in situ or invasive) & Category V (Malignant) respectively. Specificity, sensitivity, diagnostic accuracy, negative and positive predictive value of FNAC were calculated and cyto-histopathological correlation assessed wherever possible.

Results: Out of 468 breast lesions reported on FNAC, the category wise distribution was - Category I, II, III, IV & V accounting for 23(4.9%), 342(73.07%), 7(1.5%), 11(2.35%) and 85(18.16%) respectively. Histopathology was performed in 331/468 cases with cyto histological concordance of 98.4% and a type agreement rate of 90.9%. The sensitivity, specificity, positive and negative predictive value and diagnostic accuracy was 98.90%, 99.16%, 97.82%, 99.58% and 99.09% respectively.

Conclusion: FNAC is a simple, reliable, cost effective, first line diagnostic procedure for all breast lumps. In collaboration with physical examination and imaging studies (triple approach), FNAC is a highly sensitive diagnostic tool. Adopting a universally acceptable standardized reporting system for breast cytology can enhance the diagnostic accuracy of FNAC.