The OncoSim-Cervix cancer microsimulation model: Unveiling roll-out strategies for human papillomavirus primary testing.

Abstract

Background: Globally, cervical cancer is one of the most common cancers, yet it is largely preventable. Switching methods for primary screening from cytology testing, via Pap test, to human papillomavirus (HPV) testing is a component of that prevention. OncoSim-Cervix, a Canadian cervical cancer microsimulation model, assesses the long-term effects of HPV vaccination and screening interventions. This study projects the impact of differing roll-out strategies for HPV primary testing for cervical cancer screening in Canada.

Data and methods: OncoSim-Cervix simulates the progression from HPV infection to cervical cancer, incorporating Canadian data on incidence, mortality, HPV vaccination, screening, and costs. This analysis compared the effect of different roll-out strategies for switching from current practice to HPV primary screening every five years. Using OncoSim-Cervix, the study simulated one status quo scenario (cytology primary screening every three years) and three quinquennial HPV primary screening scenarios: (1) one-time roll-out, (2) population-based roll-out over two years, and (3) age-based roll-out over three years.

Results: All HPV screening roll-out strategies were found to improve clinical outcomes, with reductions of approximately 20% in cervical cancer cases and 18% in deaths, while screening less frequently, compared with cytology screening. The one-time roll-out scenario initially spiked colposcopy referrals by 60%, while phased implementation produced smaller peaks (35% to 40%) followed by declining referrals, compared with cytology screening.

Interpretation: Switching from three-year cytology to five-year HPV testing improves outcomes, with phased strategies mitigating the initial colposcopy surge. Modelling can help programs anticipate and manage colposcopy demand during the transition.