50 years of screening in the Nordic countries: quantifying the effects on cervical cancer incidence

TLDR

Cervical cancer incidence in the Nordic countries would have been comparable to the highest rates seen in low‑income countries, underscoring the need to evaluate long‑term screening benefits. Ad hoc‑refined age‑period‑cohort models were applied to 50‑year incidence data from Denmark, Finland, Norway and Sweden to project expected cervical cancer cases in a no‑screening scenario. The models predict that without screening, incidence would have been 3–5 times higher, with over 60,000 cases (41–49%) prevented, suggesting screening programmes averted an HPV‑driven cervical cancer epidemic in the Nordic countries.

Abstract

Nordic countries’ data offer a unique possibility to evaluate the long-term benefit of cervical cancer screening in a context of increasing risk of human papillomavirus infection. Ad hoc-refined age-period-cohort models were applied to the last 50-year incidence data from Denmark, Finland, Norway and Sweden to project expected cervical cancer cases in a no-screening scenario. In the absence of screening, projected incidence rates for 2006–2010 in Nordic countries would have been between 3 and 5 times higher than observed rates. Over 60 000 cases or between 41 and 49% of the expected cases of cervical cancer may have been prevented by the introduction of screening in the late 1960 s and early 1970 s. Our study suggests that screening programmes might have prevented a HPV-driven epidemic of cervical cancer in Nordic countries. According to extrapolations from cohort effects, cervical cancer incidence rates in the Nordic countries would have been otherwise comparable to the highest incidence rates currently detected in low-income countries.