Introduction

Breast cancer is a leading health concern among women due to its high mortality and morbidity rates. Recent GLOBOCAN 2018 data produced by the International Agency for Research on Cancer (IARC) from 185 countries reported 2.3 million new cases of breast cancer and a mortality rate of 6.9% [1,2].

Breast cancer has been ranked as the number one cancer among Indian females, with a mortality rate of 12.7 per 100,000 women [3]. Studies conducted in India and around the world have shown a marked rise in the incidence, morbidity, and cancer-related deaths on the Indian subcontinent [4,5].

A significant proportion of surgical cases involve breast diseases in both developed and developing countries; hence, the need arises to distinguish benign from malignant lesions prior to definitive treatment. With increasing awareness of breast cancer, there has been a parallel rise in anxiety and psychological stress among women, many of whom tend to interpret any breast-related symptom as suggestive of malignancy [6].

Fine-needle aspiration cytology (FNAC) is a minimally invasive, rapid, and cost-effective diagnostic procedure that is simple to perform and associated with minimal patient discomfort. It has been found to be a very reliable method for diagnosing breast lesions prior to surgery. It is considered the quickest and most reliable method for diagnosing breast lesions [7,8,9].

We use the terminology of the IAC Yokohama System for Reporting Breast Fine Needle Aspiration Cytopathology (IAC Yokohama System) to report cytology of all palpable breast lumps [10,11].

The system is designed to establish comprehensive best practice guidelines covering the indications and technical aspects of breast fine-needle aspiration biopsy (FNAB), including smear preparation [12]. Furthermore, it aims to develop structured checklists of essential cytological features to assist in the accurate diagnosis of specific breast lesions and to improve the overall interpretation of breast cytology smears [13].

Cytological grading of breast carcinoma was performed according to Robinson’s criteria, which incorporate six cytological parameters: cell dissociation, nuclear size, cell uniformity, nucleoli, nuclear margins, and chromatin pattern. Each parameter is scored on a scale of 1 to 3, and the aggregate score is used to derive the final cytological grade. Scores between 6 and 11 were assigned a grade of 1, scores between 12 and 14 were assigned a grade of 2, and scores between 15 and 18 were assigned a grade of 3 [14,15,16].

The IAC Yokohama System is employed to evaluate diagnostic and prognostic ancillary techniques and to offer evidence-based recommendations for their application [17,18]. Furthermore, it promotes standardized reporting by introducing well-defined categorical terminology, thereby ensuring international reproducibility and providing a structured format for reporting breast cytology findings [19].

Additionally, the integration of well-defined diagnostic categories with corresponding management recommendations and options strengthens training and quality assurance measures, thereby facilitating wider acceptance and utilization of the system among clinicians.

It includes five diagnostic categories: insufficient/inadequate (code 1), benign (code 2), atypical (code 3), suspicious of malignancy (code 4), and malignant (code 5). The risk of malignancy (ROM) for each category is calculated with the exact 95% binomial CIs [20,21,22]. This study was conducted to determine the profile of breast lesions on FNAC, classify them into the five diagnostic categories, and determine the diagnostic performance of FNAC, including its sensitivity and specificity in distinguishing benign from malignant lesions, through correlation with corresponding histopathological findings.