Modelling the overdiagnosis of breast cancer due to mammography screening in womenaged 40 to 49 in the United Kingdom

Table 5 Comparison of the number of cancers detected for 1,000,000 women in annualscreening between ages 40 to 49 years versus no screening versus.

	Ages 40 to 49		Ages 50 to 54		Ages 40 to 54
	Group 1 Annual screening	Group 2 No screening	Group 1 No screening	Group 2 No screening	Group 1 Total	Group 2 Total
Base-case
Screen-detected
Invasive	7772	-	-	-	7772	-
Progressive in situ	1145	-	-	-	1145	-
Non-progressive in situ	874	-	-	-	874	-
Clinically detected
Invasive	5693	14 089	7680	8151	13 373	22 240
Non-progressive in situ	546	1336	658	728	1204	2064
*All cancers*	16 030	15 425	8338	8879	24 368	24 304
Overdiagnosis
Absolute number	605		-541		64
% of screen-detected	6.2				0.7
% of cancers diagnosed within ages 40 to 49	3.8				0.4

ISSN: 1465-542X