Diagnostic Accuracy of Opportunistic Breast Cancer Screening Based on Mammography in Iran

Background: Although breast cancer is the most prevalent type of cancer among Iranian women, its screening is opportunistic in Iran. The available guidelines for breast cancer screening are based on mammography. A screening modality should have adequate diagnostic accuracy and be widely available at reasonable cost. Although mammography is highly accessible in Iran, its accuracy has not been investigated. Objectives: This study aimed to evaluate the accuracy of mammography in opportunistic screening regarding the current rate of patient attendance. Patients and Methods: A total of 491 women undergoing screening mammography were followed-up based on their medical records. They were divided into positive and negative screening groups, based on the breast imaging-reporting and data system (BI-RADS) categories and approaches. To evaluate the disease status of positive cases, pathology reports were investigated, and negative cases were followed-up for stability over time. Results: In the study sample, sensitivity was estimated at 73.08% (95% CI: 55.21 - 88.93), specificity was estimated at 94.41% (95% CI: 91.91 - 96.32), and accuracy was 93.28% (95% CI: 90.69 - 95.33). These test accuracy indices were not significantly different between the groups regarding age, family history, breast density, and history of breast interventions. Conclusion: The test’s sensitivity or ability to detect a disease was relatively low in opportunistic screening; it was found to be similar to the results of studies of first time implementation of screeninng. In both settings, a test needs to diagnose both incident and prevalent cases. The overall accuracy of mammography was acceptable, even in opportunistic screening.