Impact of invitation schemes on breast cancer screening coverage: a cohort study from Copenhagen, Denmark

Katja Kemp Jacobsen, My von Euler Chelpin, Ilse Vejborg, Elsebeth Lynge

Publikation: Bidrag til tidsskriftTidsskriftsartikelForskningpeer review


Background: The purpose of mammography screening is to decrease breast cancer mortality. To achieve this a high coverage
by examination is needed. Within an organized screening programme, we examined the impact of changes in the invitation
schedule on the interplay between coverage and participation.
Method: We studied nine cohorts aged 50–51 when first targeted by mammography screening in Copenhagen, Denmark.
Population data were retrieved from the Danish Civil Registration System; invitation and attendance data from the screening
programme database. Data were linked using unique personal identification numbers. Coverage by invitation was defined as
(number of invited women/number of targeted women), coverage by examination as (number of screened women/number of
targeted women), and participation rate as (number of screened women/number of invited women).
Results: Coverage by invitation was close to or above 95% for all newly recruited cohorts. In subsequent invitation rounds,
both technical errors and changes in the invitation scheme affected the coverage by invitation. Coverage by examination at first
invitation was 72.5% for the first cohort, but dropped to 64.2% for the latest cohort. Furthermore, coverage by examination
dropped by increasing invitation number and with omission of re-invitation of previous non-attenders. Participation rate closely
reflected changes in the invitation scheme.
Conclusion: Changes in the invitation schemes influenced coverage by invitation, coverage by examination, and participation
rate. We observed a considerable gap between coverage by examination and participation rate, strongly indicating that the
latter cannot without reservations, be taken as an indicator of the first.
TidsskriftJournal of Medical Screening
Udgave nummer1
Sider (fra-til)20-26
StatusUdgivet - 1 mar. 2017
Udgivet eksterntJa