With an established UK school based HPV immunisation programme, the approach to cervical screening requires modification to optimise cancer prevention, but retain clinical and economic efficiency.
A Markov simulation model has been constructed for a cohort of 35,000 women who are followed from age 12 until age 75. The model considers possible acquisition of HPV and regression or progression of disease in a similar fashion to the natural history model of Choi, 2009. Women are assigned a risk level for sexual activity and a deprivation quintile. Current national data indicates these factors impact on risk of HPV infection, uptake of vaccination and attendance at screening.
The model estimates the rates of cervical cancer, rates of CIN, numbers of colposcopies per year and the relative costs of different screening strategies and subsequent treatments in the vaccinated cohort of women.
We will demonstrate results for alternate screening strategies for referral to colposcopy – primary HPV screening either alone, or triaged by cytology. These are compared to the current practice of cytology only with HPV test of cure. We consider variation of the age and frequency of screening and examine the impact on the burden of cervical disease.
Whilst there are uncertainties present in the modelling process, the results of these models allow us to consider various “what if” scenarios and help to instruct policy on the future of the cervical screening programme in Scotland.
Choi et al, (2009) Transmission dynamic modelling of the impact of human papillomavirus vaccination in the United Kingdom. Vaccine 28: 4091-4102