Table 1. Definition of regularly, irregularly, and not screened depending on age at case diagnosis.

Age at diagnosis (years)	25–34	35–64	65+
Screening window under consideration	Age 25.5–28.5 years: screening 22.5–25.5 years Age 28.5–31.5 years: screening 22.5–28.5 years Age 31.5–35 years: screening 22.5–31.5 years	Screening 15 years before diagnosis	Screening at ages 50–64 years
Regularly screened	Age 25.5–28.5 years: screened 22.5–25.5 years Age 28.5–31.5 years: screened 22.5–25.5 and 25.5–28.5 years Age 31.4–35: screened 22.5–25.5, 25.5–28.5, and 28.5–31.5 years	Age 35–49 years: maximum interval between tests is ⩽3.5 years Age 50–64 years: maximum interval between tests is ⩽5.5 years	Maximum interval between tests is ⩽5.5 years
Irregularly screened	Age 28.5–31.5 years: screened 22.5–28.5 years, but not regularly Age 31.4–35 years: screened 22.5–31.5 years, but not regularly	Age 35–49 years: maximum interval is 3.5–7.5 years Age 50–64 years: maximum interval is 5.5–7.5 years	Maximum interval is 5.5–7.5 years
Very irregularly screened	NA	Maximum interval is 7.5–13 years	Maximum interval is 7.5–13 years
Not (or nearly never) screened	Age 25.5–28.5 years: not screened 22.5–25.5 years Age 28.5–31.5 years: not screened 22.5–28.5 years Age 31.5–35 years: not screened 22.5–31.5 years	No screen in window or maximum interval is >13 years	No screen in window or maximum interval is >13 years