Jacky Luiten

20 | Chapter 2 Results Trends in overall screening outcome This study comprised a total of 484,422 screening mammography examinations (52,613 initial screens and 431,809 subsequent screens), obtained between July 2005 and July 2015 (Table 2.1). During this 10‐year period the biennial number of screening examinations gradually increased from 66,750 (2005‐2007) to 131,224 (2013‐2015). In the same period, the recall rate increased from 1.3% (2005‐2007) to 3.3% (2013‐2015). A total of 12,965 women were recalled for further analysis of a screen‐detected abnormality (average recall rate 2.7%). Out of 3059 true positive recalls 623 patients were diagnosed with DCIS and 2436 patients with invasive carcinoma. The cancer detection rate (CDR) for the total period was 6.3 per 1000 women screened and gradually increased from 4.9 per 1000 (2005‐2007) to 7.0 per 1000 (2013‐2015, Table 2.1). The positive predictive value of recall was 23.6% for the total period and decreased from 36.9% (2005‐2007) to 21.3% (2013‐2015) during the 10‐year screening period. Table 2.1 Overall screening outcome at bi‐annual screening mammography. Year of screening 05/07 07/09 09/11 11/13 13/15 Total Screens 66,750 66,558 101,249 118,641 131,224 484,422 Recalls (%) 895 (1.3) 1020 (1.5) 2945 (2.9) 3737 (3.1) 4368 (3.3) 12,965 (2.7) Screen–film mammography (%) 895 (100) 979 (96.0) 204 (6.9) – – 2078 (16.0) Full–field digital (%) – 41 (4.0) 2741(93.1) 3737 (100) 4368 (100) 10,887 (84.0) True positive recalls 327 332 676 799 925 3059 DCIS (%) 65 (19.9) 56 (16.9) 157 (23.2) 181 (22.7) 164 (17.7) 623 (20.4) Invasive carcinoma (%) 262 (80.1) 276 (83.2) 519 (76.8) 618 (77.3) 761 (82.3) 2436 (79.6) Positive predictive value of recall, % 36.5 32.5 23.0 21.4 21.2 23.6 Cancer detection rate per 1000 screens 4.9 5.0 6.7 6.7 7.0 6.3 Initial versus subsequent screens At initial screening, 397 women (13.0% of all cancers diagnosed following recall) were diagnosed with either DCIS or invasive breast cancer (DCIS: 113 women, invasive carcinomas: 284 women) compared to 2662 women (87.0%) at subsequent screening (DCIS; 510 patients, invasive carcinomas; 2152 patients).