Impact of organized and opportunistic Pap testing on the risk of cervical cancer in young women - A case-control study from Finland

Objective. Effectiveness of organized cervical cancer screening has been shown in several studies. However, screening among women aged <25 years has been suggested to have little or no impact on the risk of cervical cancer. Also the significance of opportunistic testing in preventing cervical cancer is unclear. The aim of this study was to clarify the effect of opportunistic testing and organized screening on the risk of cervical cancer among young Finnish women. Methods. In the Finnish Cancer Registry there were 284 cervical cancer cases diagnosed and tested below the age of 40 in 2004-2009. Screening histories and data on opportunistic testing for these women and their 1698 age-matched controls were derived from databases of the Mass Screening Registry and The National Institute for Health and Welfare from 1997 onward. OR's and 95% CI's for the association of cervical cancer diagnosis and participation in organized screening and opportunistic testing were estimated using unconditional logistic regression. Results were corrected for self-selection bias and attendance rate. Results. Among women aged under 25, OR of cervical cancer for any Pap test taken 0.5-5.5 years before diagnosis was 1.25 (95% CI 0.46-3.43). Attending only organized screening at age 25-39 resulted in OR 0.52 (0.36-0.77), attending only opportunistic testing in OR 0.86 (0.60-1.25) and attending both in OR 0.48 (0.29-0.79). Conclusion. Opportunistic testing showed no clear additional benefit on preventing cervical cancer. The study also supports findings on a smaller effect of screening in younger age groups. (C) 2017 The Authors. Published by Elsevier Inc.