Presentation (CTI)

OBJECTIVES: Cost estimation is vital to economic modelling, but data gaps can create methodological challenges. This study aims to conceptualise a framework to estimate costs for economic models in the absence of relevant data across different European countries using human papillomavirus (HPV)-related cancers as an example.
METHODS: A targeted literature review (TLR) highlighted a critical lack of evidence regarding the lifetime direct costs across 11 HPV-related cancers. A framework was developed to address data gaps using a literature-informed, proxy-based extrapolation approach by grouping countries by healthcare system archetypes, identifying appropriate proxies across country and cancer type, and approximating lifetime costs.
RESULTS: The TLR identified seven studies which reported lifetime costs for seven HPV cancers across nine European countries. A pragmatic search identified three key papers that grouped countries into European healthcare system archetypes (Bismarck, Beveridge, Nordic, Southern European). Countries without data were assigned to a proxy country, within the same archetype, with available data. Studies were ranked based upon whether results were disaggregated by cancer type and sex. All costs were converted to Euros and inflated to 2024 costs. All papers reported cervical cancer costs. The highest-ranking study contained reported lifetime costs for cervical, anal, oropharynx, vulva and penile cancers. Cervical cancer cost was used as a basis to derive cost ratios between cancer types. Where appropriate, a cost ratio informing sex-differences in lifetime costs was also derived. These were applied to proxy countries. Assumptions, proxy inputs and approach were refined through stakeholder feedback.
CONCLUSIONS: This framework systematically applies archetypes and proxies across cancer types and countries enhancing internal consistency and transparency versus an ad hoc approach of utilising neighbouring countries data. Although assumption-heavy, it provided a pragmatic and effective starting point in stakeholder discussions by bridging the data gap.