First steps in optimizing breast screening in Mongolia: Understanding radiologists’ performance in reading mammograms and mammographic breast density

Advanced diagnoses of breast cancer have become a serious public health issue in Mongolia. Whilst mammography has been proven to be an effective screening approach for breast cancer and well established amongst developed countries, such program has not been introduced in Mongolia. In addition in Mongolia, a lack of research around breast cancer continues to exist. The purpose of this thesis is to understand mammographic diagnostic accuracy and mammographic breast density (MD) in Mongolia, both of which are important considerations, which will inform a future national screening program. To address this aim, three studies were conducted; the first two were radiologists’ performance studies in reading mammograms with different levels of difficulty. The mammographic detection of Mongolian radiologists (case sensitivity of 63% and lesion sensitivity of 34%) was substantially lower compared with that of Australian radiologists. The third study investigated the MD features of 1985 Mongolian women using the Breast Imaging Reporting and Data system (BI-RADS) density categories. The majority of women (58%) were found to have low-density categories (category A and B) and significant associations were observed between MD; age (OR = 6.8, 95% CI: 5.5, 8.0), weight (OR = 4.5, 95% CI: 3.4, 6.0) and BMI (OR=13.2, 95% CI: 8.6, 20.0). Findings from this research have demonstrated that mammographic diagnostic accuracy is sub-optimal in Mongolia. Moreover, images with different levels of difficulty did not alter the reading performance of Mongolian radiologists suggesting the need for improving breast cancer detection skills urgently. The output of this work also demonstrated that low density was predominant in Mongolia. The results will impact on health policy around screening in Mongolia. They will inform educational strategies that are needed to transform diagnostic efficacy and will provide a good basis for decision making around screening modality choices