Prevalence and Acr Bi-rads Categorization of Mammographic Calcifications With Histopathological Correlation of the Suspicious Categories at the Kenyatta National Hospital

Abstract

Background: The incidence of breast cancer has been on the rise. Breast cancer causes the third highest number of deaths in relation to all cancers in Kenya. Mammography is currently the optimal screening and diagnostic imaging modality for identifying breast cancer and breast calcifications. Other imaging modalities such as breast ultrasound and MRI are suboptimal in detecting calcifications. Mammographic Calcifications, when present, are known indicators of benign and malignant breast diseases. Their distribution and morphology can determine the next course of action for diagnosis and management. Mammographic calcifications patterns have been utilized in western countries based on extensive studies done there. The breast calcification patterns in terms of morphologies and distribution guide further imaging and management. There is need for local studies to form a baseline for our breast imaging. Broad Objective: The objective of this study was to determine the prevalence and pattern of mammographic calcifications and to correlate the suspicious categories to histopathology in clients undergoing mammography at the radiology department at the Kenyatta National Hospital. Study design and site: Prospective descriptive study at the radiology department, mammography unit of Kenyatta National Hospital, serving the women in Nairobi county and as a national referral institution for other counties and East African region. Methodology: Ethical approval was sought from KNH-UoN ERC. The study enrolled 190 participants from the clients who required mammographic evaluation as per inclusion and exclusion criteria following informed consent obtained, between February and June 2021. Their demographic and relevant risk factors as well as mammographic characteristics were collected in a predesigned data collection tool. Mammographic images obtained were analyzed and reports prepared by the principal investigator and breast imaging specialists with a composite experience of 10 years. Participants whose mammograms had suspicious calcifications (BIRADS 3-5) underwent ultrasound guided core needle biopsy. Differential and inferential data analysis was done using SPSS Chicago Illinois version 21. Main outcomes: The mean age of the clients was 53.9(SD=10.8) years respectively. The median age was 53.0 (IQR=46.0-60.) years. They were all females. The ages of the clients ranged between 35-101years. Mammographic calcifications were detected in 40% of the participants. Macro calcifications were 45 (23.7%) while micro calcifications were 32 (16.8%) of the total population. The most frequent type of macro calcification was the vascular type,12 (15.6%) whereas for micro calcifications it was the punctate type, 12 (15.6%). Majority of calcifications were found at the upper outer quadrant of the breast, seen in 20 (26%). The most frequent categories were 1 and 2, accounting for 52 (67.5%) of all the calcifications. In the correlation of 25 suspicious calcifications (categorized as BIRADS 3 to 5) with their histopathological analysis, the sensitivity was 94.7%, specificity was 16.7%, positive predictive value was 78.3%, negative predictive value was 50%, diagnostic accuracy was 76.0%. xiii Conclusion and recommendations: The study has shown that mammographic calcifications are a common finding, with the benign category being commoner. Suspicious categories have a relatively significant diagnostic accuracy with histopathological analysis. Spot compression with magnification view and/or follow up in 6months is recommended for all suspicious categories (BIRADS 3) especially if there is low index of suspicion for malignancy. Biopsy is recommended for BIRADS 4 & 5 in cases of high suspicion for malignancy. Overall mammographic micro calcifications can help to identify breast malignancy.