RESUMO
BACKGROUND: Breast cancer is the most common cancer in females worldwide. Screening with mammography for early breast cancer detection is standard community practice in many countries. OBJECTIVE: Identify causes of missed breast cancers during screening. DESIGN: Retrospective, observational. SETTING: Department of radiology at a tertiary-care hospital mammographic screening facility. PATIENTS AND METHODS: All women who came with initial negative screens from July 2015 to July 2018 were retrospectively reviewed and followed-up for their second or subsequent mammographic screening. Missed breast cancer was defined as a cancer that was detected on a subsequent mammogram with an initial negative screen. Mammograms were interpreted by two radiologists as per BIRADS (Breast Imaging Reporting and Data System) lexicon. Causes of missed breast cancers were categorized as imaging acquisition (IA), imaging feature (IF) and imaging interpretation (II). True (occult) incident breast cancers were also documented. Percentage estimations for these causes were calculated. MAIN OUTCOME MEASURES: Breast cancer detection on follow-up screening. SAMPLE SIZE: 943 women. RESULTS: Of 15 (1.6%) screening-detected breast cancers, 7 cases (46.6%) were missed on the initial screen; 3 (43%) of these were II related, 2 (28.5%) of each were IA and IF. The remaining true (occult) cases were detected on either the second (5 cases) or third screens (3 cases). CONCLUSION: Improved screening facilities, quality mammographic acquisition and interpretation, double reading, and implementation of an organized screening program may help to avoid missed breast cancers. LIMITATIONS: Retrospective, small sample, single center, and short duration study. CONFLICT OF INTEREST: None.
