SS 03-08What can models tell us about screening in the post-nonavalent vaccine era?

29. Economics and modelling
K. Simms 1, M. Smith 2, J.B. Lew 3, H. Kitchener 4, P. Castle 5, K. Canfell 2.
1Cancer Research Division, Cancer Council NSW, 153 Dowling Street, Woolloomooloo, Sydney, NSW, 2011, Australia and Prince of Wales Clinical School, The University of New South Wales, Australia (UNSW is a previous affiliation for KS, MS and KC) (Australia), 2Cancer Research Division, Cancer Council NSW, 153 Dowling Street, Woolloomooloo, Sydney, NSW, 2011, Australia, Prince of Wales Clinical School, The University of New South Wales, Australia (UNSW is a previous affiliation for KS, MS and KC) and School of Public Health, University of Sydney, Australia (Australia), 3Cancer Research Division, Cancer Council NSW, 153 Dowling Street, Woolloomooloo, Sydney, NSW, 2011, Australia and Prince of Wales Clinical School, The University of New South Wales, Australia (Australia), 4Institute of Cancer Sciences, University of Manchester, UK (United Kingdom), 5Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY and Global Coalition against Cervical Cancer, Arlington, VA (United States)

Background / Objectives

Background: A next generation nonavalent vaccine (HPV9; Gardasil-9) is being introduced in several countries. The lifetime risk of cervical cancer in cohorts offered this vaccine will be substantially reduced but it is not known whether cervical screening in these cohorts will remain cost-effective. Models can be used to characterize the outcomes from progressively less intensive screening strategies and thus inform determination of the optimal number of cervical cancer screening tests in a woman’s lifetime for individuals or cohorts offered HPV9.

Objective: To evaluate whether cervical screening will remain cost-effective in cohorts offered nonavalent vaccines and if so, to characterize the optimal number of screening tests.


Methods

We performed a modelled evaluation using a dynamic model of HPV vaccination and cervical screening for four countries – the USA, New Zealand (NZ), Australia and England. For each country, we considered local factors including vaccine uptake rates (USA/NZ uptake ~50%; Australia/England uptake >70%);, attributable fractions of HPV9-included types, demographic factors, costs and indicative willingness-to-pay (WTP) thresholds. The most cost-effective screening strategy was assessed for cohorts offered HPV9.


Results

In the USA, four screens per lifetime was the most cost-effective option, with a 34% probability of being the optimal strategy at WTP US$50,000/LYS, and 84% probability at US$100,000/LYS. In New Zealand, five screens was the most cost-effective, with 100% probability of being optimal at NZ$42,000/LYS. In Australia, two screens was the most cost-effective option, with 62% probability of being optimal at AU$50,000/LYS. In England, four screens was the most cost-effective option, with 32% probability of being optimal at WTP of GB£20,000/QALY, increasing to 92% probability at GB£30,000/QALY


Conclusion

Some form of cervical screening is still likely to be cost-effective in cohorts of young females offered the nonavalent vaccine, even in countries with high vaccine uptake, but the optimal number of lifetime screens varies by country. 


References