An audit of Fine Needle Aspiration (FNA) biopsy of palpable breast lesions at Kenyatta National Hospital (KNH)

Abstract

Objective: To audit the FNA biopsy in the diagnosis of palpable breast lesions and assessthe influence of the technique on patient management. Methods: This was a retrospective study of 215 FNA biopsy results of palpable breast lesionsin correlation with histology results of 202 patients screened between l " January 1998to 31st December 1999 by the Human Pathology Department at Kenyatta National Hospital. The method of analysis used in this study is adopted from the one commonly used for auditing statistical data and quality assurance of FNA biopsy by the National Breast Screening Programme in the United Kingdom. Results: The results show absolute sensitivity of 76.9%, complete sensitivity of 84.6%, specificity (biopsied cases only) of 83.7%, specificity (full) of 82.2%, positive predictive value of 100%, negative predictive value of 98.2%, false positive rate 0%, false negative rate of 2.6%, inadequate rate of 14.0%, inadequacy rate for cancer of 12.8% and suspicious rate of 5.6%, (confidence interval of 90%). All the accuracy parameters fall within the set standards with exception of inadequacy rate for cancer which is higher than the expected value ( <10%). The total number of patients diagnosed with breast carcinoma were 72 among which 71 were female and ] male. All the carcinomas were ductal carcinoma with the exception of one papillary adenocarcinoma and one intraductual carcinoma (non-invasive carcinoma). Preoperation therapeutic decision was made in 63 (87.5%) patients with breast carcinoma after considering cytology results while 9 (12.5%) of patients with breast carcinoma required confirmation of malignancy. Seventy seven patients with benign breast lesions underwent lumpectomy/excision/incision biopsy after considering cytology results while 34 patients had no histological confirmation of the benign breast lesion. Conclusion: This study demonstrates that FNA biopsy is an accurate, non-invasive diagnostic procedure for assessment of palpable breast lesions. However, due to the higher inadequacy rate for cancer than the set standard there is need to improve the technical accuracy of FNA biopsy at KNH. This could be done by microscopic assessment of specimen adequacy during sampling when required. The clinician may plan for appropriate therapy for each individual patient based on clinical history and unequivocalcytology report (without the need of excision/incision biopsy in the majority of the cases).