BI-RADS application for breast cancer screening in primary healthcare settings: assessing protocol adherence and diagnostic validity.

Background: The application performance of the Breast Imaging-Reporting and Data System (BI-RADS) in primary healthcare settings remains uncertain. The normativity of BI-RADS classification and the efficacy of breast cancer detection guided by BI-RADS classification were evaluated here. Methods: All data used in the current study were derived from a breast cancer screening cohort baseline database, which consists of 8,996 women aged 35-64 years from Central China. Participants aged 35-44 underwent automated breast ultrasound (ABUS) and handheld ultrasound (HHUS), while those aged 45-64 were screened with ABUS, HHUS, and mammography (MG). All imaging diagnoses were made by radiologists according to the BI-RADS 5 Results: Of individuals found with irregular morphology, 44%, 45.7% and 77.4% were classified as BI-RADS category 4 or higher for HHUS, ABUS and MG, respectively; For those with indistinct margins, the proportion was 81%, 77.5% and 40.8%, correspondingly; For grouped calcifications, they were 100% for HHUS and 85.7% for MG; Meanwhile, 72.7% and 88.9% not parallel (taller than wide) masses were categorized as BI-RADS category 4 for HHUS and ABUS. The concordance of BI-RADS classification was as high as 98.2% between HHUS and ABUS (Kappa = 0.726), whereas it was about 96% between ultrasound and MG (Kappa ranged from 0.21 to 0.25). The BI-RADS guided screening performance for breast cancer showed AUC values of 0.9935 for ABUS, 0.9529 for HHUS, 0.8983 for MG. If the BI-RADS diagnosis of MG was considered in ultrasound-negative women, only the HHUS's performance was boosted, achieving an AUC of 0.9920. Conclusions: Radiologists at primary hospitals can effectively apply BI-RADS based on the malignant features they found. BI-RADS can provide a reliable framework for guiding breast cancer screening in primary healthcare settings.