Jacky Luiten

Recall and outcome of screen‐detected microcalcifications of mammography screening | 67 5 Introduction Fine calcifications of the breast, so‐called microcalcifications, were first described by the German surgeon Salomon in 1913. 1 They are defined as tiny grouped calcareous deposits in terminal ductal lobular units of the breast and originate from intraluminal secretions or necrosis of epithelial cells. Microcalcifications visible at mammography may be an early sign‐and sometimes even the only sign‐of underlying early breast cancer or ductal carcinoma in situ (DCIS). 2‐4 Up to 90% of DCIS is not palpable and is diagnosed at the work‐up of suspicious microcalcifications seen at mammography. 5,6 Following the introduction of a nationwide biennial mammography screening program in the Netherlands in 1989, a considerable increase in the incidence of DCIS has been reported. 7,8 Moreover, the replacement of screen‐film mammography (SFM) by full‐field digital mammography (FFDM) in the Dutch mammography screening program between 2009 and 2010 (transition period) further contributed to this increase. 7‐9 Since 1995, data on all screened women in the southern region of the Netherlands have been recorded in a database. This database is used for quality assurance and improvement of the screening program. We have recently reported on the overall trends in incidence and tumor grade of screen‐detected DCIS and invasive carcinoma and the use of surgical excision biopsies during two decades of mammography screening. 9,10 Most DCIS lesions are detected at mammography screening by the presence of microcalcifications. However, not all microcalcifications found at screening are related to underlying DCIS. Little is known about the trends in the detection of microcalcifications at mammography screening and the yield of these findings after recall. Digital mammography has a higher sensitivity than SFM for the detection of microcalcifications, resulting in increased recall rates for calcifications during the transition from SFM to FFDM screening. 11 Furthermore, once microcalcification‐ associated DCIS is diagnosed, the potential for overdiagnosis and overtreatment, especially with low grade DCIS, is a serious concern. Therefore, the purpose of this study was to determine the trends in recall of suspicious microcalcifications and their outcomes during two decades of mammography screening. We analyzed the yield of microcalcifications, expressed as the cancer detection rate (CDR; the number of [pre]malignant abnormalities per 1000 screening examinations) and the histologic grade at current digital mammography screening compared with that in the era of SFM. More specifically, we determined to which degree the changes in recall of microcalcifications and the