Modeling the impact of screening policy and screening compliance on incidence and mortality of cervical cancer in the post-HPV vaccination era.

BACKGROUND: In Norway, pap smear screening target women aged 25-69 years on a triennial basis. The introduction of human papillomavirus (HPV) mass immunization in 2009 raises questions regarding the cost-saving future changes to current screening strategies.
METHODS: We calibrated a dynamic HPV transmission model to Norwegian data and assessed the impact of changing screening 20 or 30 years after vaccine introduction, assuming 60 or 90% vaccination coverage. Screening compliance among vaccinated women was assumed at 80 or 50%. Strategies considered: (i) 5-yearly screening of women of 25-69 years, (ii) 3-yearly screening of women of 30-69 years and (iii) 3-yearly screening of women of 25-59 years.
RESULTS: Greatest health gains were accomplished by ensuring a high vaccine uptake. In 2060, cervical cancer incidence was reduced by an estimated 36-57% compared with that of no vaccination. Stopping screening at the age of 60 years, excluding opportunistic screening, increased cervical cancer incidence by 3% (2060) compared with maintaining the current screening strategy, resulting in 1.0-2.4% extra cancers (2010-2060). The 5-yearly screening strategy elevated cervical cancer incidence by 30% resulting in 4.7-11.3% additional cancers.
CONCLUSION: High vaccine uptake in the years to come is of primary concern. Screening of young women <30 years remains important, even under the conditions of high vaccine coverage.