Overdiagnosis in the population-based organized breast cancer screening program estimated by a non-homogeneous multi-state model: a cohort study using individual data with long-term follow-up

Table 2 Number of person-years, invasive breast cancer cases by detection mode, interval cancer ratio, and breast cancer incidence by age group

Age at invitation	Person-years	PSD	SSD	IC	NP	IC ratio (%)^a	BCI (per 10⁵)^b
50–54	1,163,586.1	875	721	736	697	31.6	260
55–59	1,264,796.0	277	1507	955	793	34.9	279
60–64	1,098,407.1	316	2001	872	655	27.3	350
65–69^c	1,157,223.7	331	2277	975	660	27.2	367
Total	4,684,012.9	1799	6506	3538	2805	29.9	313

Abbreviations: BCI breast cancer incidence, IC interval cancer, NP non-participant, PSD prevalent screen-detected cases, SSD subsequent screen-detected cases
^aNumber of ICs divided by the sum of screen-detected and ICs
^bTotal number of breast cancers divided by person-years
^c9.65% of the women were also invited to screening at age 70–74 from 2012

ISSN: 1465-542X