Self-sampling versus reminder letter: effects on cervical cancer screening attendance and coverage in Finland

Optimizing attendance and coverage of organized screening is needed to reduce cervical cancer incidence to previous lower levels. In our study, all nonparticipants in organized cervical cancer screening in 2008 in Espoo, Finland were randomized to receive a self-sampling kit (1,130 women) or a reminder letter (3,030 women). Effects on screening coverage were assessed according to the self-reported previous Pap smear history of the participants. Participation rate in the self-sampling arm, 29.8%, was significantly higher than in the reminder letter arm, 26.2% (adjusted relative risk for participation 1.13). Total participation in Espoo in 2008 rose significantly after the two interventions from 64.0 to 75.4%. In both arms, similar to 20% of the participants after second intervention could be considered under screened (previous Pap smear >= 5 years ago) and thus increased screening coverage. Respectively, for 70-75%, the second intervention only provided overscreening. Participation was lowest among young age groups and immigrants, after primary invitation and after interventions. Our study shows that a second intervention for nonattendees after the first invitation is needed to optimize the attendance rates. Self-sampling might be slightly more successful in this, but the effects on screening coverage were similar in both groups.