Improving cervical cancer screening attendance in Finland.

High attendance is essential to cervical cancer screening results. Attendance in the Finnish program is currently at 70%, but extensive opportunistic screening occurs beside the organized. A shift from opportunistic to organized screening is imperative to optimize the costs and impact of screening and minimize potential harms. We evaluated the effect of reminder letters (1st reminder) and self-sampling test (2nd reminder) on program attendance. The study population consisted of 31,053 screening invitees in 31 Finnish municipalities. 8,284 non-attendees after one invitation received a reminder letter and 4,536 further non-attendees were offered a self-sampling option. Socioeconomic factors related to participation were clarified by combining screening data to data from Statistics Finland. Reminder letters increased participation from 72.6% (95% CI 72.1, 73.1) to 79.2% (95% CI 78.8, 79.7) and self-sampling further to 82.2% (95% CI 81.8, 82.7). Reminder letters with scheduled appointments resulted in higher increase than open invitations (10 vs. 6%). Screening of original non-attendees increased the yield of CIN3+ lesions by 24%. Non-attendance was associated with young age, immigrant background, lower education level and having never been married. We showed that a total attendance of well over 80% can be achieved within an organized program when the invitational protocol is carefully arranged.