On analyzing and predicting cervical cancer trends in Finland

Cervical cancer is largely preventable because its primary cause, a persistent infection with human papillomavirus (HPV), is well understood and can be addressed through HPV vaccination and effective screening. Despite substantial progress in many high-income countries, cervical cancer remains a major burden globally, motivating the World Health Organization’s (WHO) strategy to eliminate cervical cancer as a public health problem, defined by an incidence below 4 per 100 000 woman years. In this thesis, Finnish cervical cancer trends are examined using registry-based data on incidence and mortality, together with screening participation and HPV vaccination coverage data. The work combines descriptive analyses with statistical tests (proportion tests and correlation tests) and a simplified scenario-based forecast of future incidence under differing HPV vaccination coverage assumptions. Historically, the launch of Finland’s screening program led to a strong decline in cervical cancer incidence and mortality, yet recent patterns indicate an upward trend. Age-standardized incidence reached its lowest level in 2005 (4.7 per 100 000 person years) and has trended upward since; the increase is particularly visible in young to middle-aged cohorts. In contrast, mortality has remained low and stable over the past decade (∼1.5–2 per 100 000 person years). Screening invitation coverage is close to 100% nationally, but participation remains just above 70% (71.6% in 1991, 73.1% in 2023), with lower participation among younger invitees and regional variation. The forecast demonstrates that vaccination coverage supports long-term progress but implies a slow timeline to elimination at current levels: two-dose coverage among girls aged 13–20 is 73.8%, and full-dose coverage at age 15 (2010 cohort) is 75.7%, well below the WHO target of 90%. In the forecast, incidence declines meaningfully only after vaccinated cohorts age into high-risk groups; only the 90% vaccination scenario reaches the WHO elimination threshold within the projection period. Furthermore, there also seems to be a statistically significant negative association between cervical cancer incidence and screening participation ten years earlier (national Spearman = −0.578), with an even stronger association for incidence at ages 40–49 compared to participation ten years prior at ages 30–39 (Spearman = −0.780). As such, these findings reinforce the complementary need to sustain screening participation while accelerating vaccine uptake.