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.


CONCLUSIONS
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.
Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, PO Box 1122, Blindern 0317, Oslo, Norway. b.f.d.blasio@medisin.uio.no
Birgitte Freiesleben
BF
de Blasio
Aileen Rae
AR
Neilson
Marianne
M
Klemp
Finn Egil
FE
Skjeldestad
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001071:Appointments and Schedules; D017046:Cost Savings / Q000379:methods; D055088:Early Detection of Cancer / Q000191:economics / Q000592:standards; D005260:Female; D006291:Health Policy / Q000191:economics / Q000639:trends; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D008962:Models, Theoretical; D009664:Norway / Q000453:epidemiology; D017063:Outcome Assessment, Health Care; D065006:Papanicolaou Test; D030361:Papillomavirus Infections / Q000150:complications / Q000517:prevention & control* / Q000635:transmission; D053918:Papillomavirus Vaccines / Q000008:administration & dosage* / Q000592:standards; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D014626:Vaginal Smears / Q000191:economics / Q000592:standards* / Q000706:statistics & numerical data
D053918:Papillomavirus Vaccines