Objective: To evaluate the efficacy of ultrasound-guided fine-needle aspiration cytology for the diagnosis of breast solid masses.
Materials and method: It is a retrospective study with 705 patients carrying a solid breast mass who underwent ultrasound-guided fine-needle aspiration cytology for the diagnosis. The fine needle aspiration cytology (FNAC) was performed with ultrasound guidance and a 21 G gauge needle was used. The cytological results were classified as benign, suspicious, malignant or insufficient. The benign results were considered negative for malignancy and the malignant and suspect results were considered positive for malignancy. Insufficient results were not included in analysis of the accuracy of the study. In all cases the histological result of the masses was obtained and it was taken as reference test. The ultrasound-guided FNAC accuracy was evaluated for all cases and then specifically for the masses classified in the categories 3, 4 and 5 of BI-RADS.
Results: When all cases were included the results were the following: sensitivity 96%, specificity 92%, positive predictive value 97%, negative predictive value 89%, false positives 3%, false negatives 11% and overall accuracy 95%. For the BI-RADS category 3 the results were the following: sensitivity 100%, specificity 98%, positive predictive value 90%, negative predictive value 100%, false positives 10%, there were no false negatives and overall accuracy 98%.
For the BI-RADS category 4 the results were the following: sensitivity 92%, specificity 85%, positive predictive value 95%, negative predictive value 78%, false positives 5 %, false negatives 21% and overall accuracy 91%. For the BI-RADS category 5 the results were the following: sensitivity 99%, specificity 75%, positive predictive value 99.6%, negative predictive value 40%, false positives 0.4%, false negatives 60% and overall accuracy 99%.
Conclusion: Ultrasound-guided FNAC is a valuable diagnostic technique for breast solid masses. In the probably benign masses (BI-RADS 3) its objective is to rule out malignancy for safely avoid biopsy and planning an imaging follow-up. In the suspicious and highly suggestive of malignancy masses (BI-RADS 4 and 5) the objective is to confirm malignancy prior to definitive treatment, when neoadjuvant chemotherapy is not needed.