Breast cancer screening: evidence of benefit depends on the method used

Table 2 Summary of main incidence-based mortality studies on breast cancer screening.

Study	Country	Areas in study	Age of screened women	Data on treatments in screening and non-screening areas	Comparison areas where no screening existed during the entire screening period	Historical comparison areas^a	Effect of screening on the risk of BC death	Adjustment of results for:
								Self-selection	Incidence	Lead time
Tabár et al. 2003 [27]	Sweden	Dalarna and Kopparberg counties	40 to 69	No	No	No	-45%	Yes	Yes	No
Olsen et al. 2005 [28]	Denmark	Copenhagen where screening took place compared to the rest of the country	50 to 69	No	Yes	Yes	-25%	No	No	No
SOSSEG 2006 [29]	Sweden	About half of Swedish counties	40(50) to 69(74)	Yes, but only in non-participants	No	No	-27%	Yes	Yes	No
Jonsson 2007 [30]	Sweden	Four Swedish counties	40 to 74	No	Yes	No	-26%	Yes	No	Yes
Anttila et al. 2008 [31]	Finland	All the country	50 to 69	No	No	No	-11%	No	No	No
Hellquist et al. 2010 [32]	Sweden	All Swedish counties	40 to 49	No	Yes	No	-26%	Yes	No	Yes
Kalager et al. 2010 [33]	Norway	Four counties with pilot program plus comparison counties	50 to 69	No	Yes	Yes	-10% (NS)	No	No	No
Olsen et al. 2012 [34]	Norway	Four counties with pilot program plus comparison counties	50 to 69	No	Yes	Yes	-7 (NS)	No	No	No

BC: breast cancer; NS: statistically non-significant. ^aData on breast cancer death rates in historical comparison groups, that is, in screening areas and in comparison areas before screening started in screening areas.

ISSN: 1741-7015