Jacky Luiten

100 | Chapter 7 Table 7.1 Baseline characteristics. Total (%) Missing data excluded (%) Period of diagnosis n =30,417 1989 ‐ 1990 379 (1,3) 1991 ‐ 1992 713 (2,5) 1993 ‐ 1994 968 (3,4) 1995 ‐ 1996 1.084 (3,8) 1997 ‐ 1998 1.270 (4,5) 1999 ‐ 2000 1.502 (5,3) 2001 ‐ 2002 1.555 (5,5) 2003 ‐ 2004 1.750 (6,2) 2005 ‐ 2006 1.872 (6,6) 2007 ‐ 2008 2.180 (7,7) 2009 ‐ 2010 2.818 (9,9) 2011 ‐ 2012 3.238 (11,4) 2013 ‐ 2014 3.690 (13,0) 2015 ‐ 2016 3.825 (13,5) 2017 ‐ 2018 3.573 (12,6) Screen detected^ n =14,326 Yes 10,444 (72.9) No 3,469 (24.9) Unknown 413 (2.9) Treatment # n =28,357 n =27,783 Mastectomy 9,790 (34.5) (35.2) BCS + radiotherapy 13,859 (48.9) (49.9) BCS only 3,760 (13.3) (13.5) No treatment 374 (1.3) (1.3) Unknown 574 (2.0) DCIS grade* n =24,501 n =23,065 Low 3,874 (15.8) (16.8) Intermediate 7,953 (32.5) (34.5) High 11,238 (45.9) (48.7) Unknown 1,436 (5.9) Axillary treatment ALND # n =28,357 n =27,920 Yes 872 (3.1) (3.1) No 27,048 (95.4) (96.9) Unknown 437 (1.5) SLNB ± n =21,196 n =19,971 Yes 11,340 (39.1) (56.8) No 8,631 (30.4) (43.2) Unknown 1,225 (4.3) ^ data available since 2011; # data available 1995; * data available since 2001; ± data available since 2005. Breast surgery and radiotherapy for DCIS Since 1995 type of surgery was not specified in 2.0% (574/28,357) of all women diagnosed with DCIS, resulting in 27,783 women for whom type of treatment was registered. A mastectomy was performed in 9,790 (35.2%) women, 17,619 (63,4%)