Jacky Luiten

50 | Chapter 4 December 31, 2016. Women aged 50‐75 years are invited to attend biennial screening mammography, which is provided free of charge. Details of our nationwide screening program have been published previously. 8 In summary, screen‐film mammography was replaced by full‐field digital mammography in 2009‐2010. A two‐view digital mammogram (mediolateral‐oblique view and craniocaudal view) of each breast is obtained by a certified radiographer, after which the examination is assessed by two screening radiologists. Previous screening mammograms are always available for comparison. Radiologists classify mammographic abnormalities in women needing further evaluation (i.e., recall) into one of the following categories: (I) suspicious mass; (II) suspicious calcifications; (III) suspicious mass with calcifications; (IV) asymmetry; (V) architectural distortion; (VI) other. Women with normal findings (BI‐RADS 1, Breast Imaging Reporting and Data System) or benign findings (BIRADS 2) are invited to reattend subsequent screening. 9,10 The BIRADS 3 classification is not used in the Dutch screening program. Women with BI‐RADS 0, 4 or 5 are recalled for further analysis at a breast unit of a hospital. BI‐RADS 0 lesions comprise sharply demarcated masses, architectural distortions visible at one projection only and asymmetries visible at either one or both views. Masses with indistinct margins, suspicious microcalcifications and architectural distortions visible at both views are categorized as BI‐RADS 4 lesions whereas BI‐RADS 5 lesions consist of spiculated masses and suspicious masses showing calcifications. Assessment after recall and follow‐up Twenty‐five hospitals were involved in the workup of the recalled women. The majority of these women (98.8%, 11,640/11,783) were analyzed in one of the seven hospitals centrally located in our screening region. Each of these seven hospitals has a dedicated surgical breast unit and state‐of‐the‐art breast imaging equipment, whereas a total of four pathology departments deliver their services to these hospitals. At the hospital, additional imaging and biopsy procedures may be performed to establish a final diagnosis for the abnormality detected at screening mammography. We used the term CNB to cover all percutaneous histologic biopsy methods; ultrasound‐guided CNB (CNB, 14‐18G) as well as stereotactic CNB (SCNB, 9‐11G). High‐risk lesions at CNB were categorized as follows: (I) papillary lesion (consisting of papillary lesions, papillomas and papillomatosis); (II) columnar cell lesion, flat epithelial atypia; (III) atypical ductal hyperplasia; (IV) radial scar, complex sclerosing lesion; (V) LCIS, atypical lobular hyperplasia; (VI) combination of high‐risk lesions; (VII) other (e.g., granular cell tumor, atypia without further specification at biopsy). In addition to the feedback that the hospitals gave to the