Prof. Matti Lehtinen (University of Tampere, Finland)
In most European countries, HPV vaccination has been integrated in the national immunization programmes since 2008. Soon, the first vaccinated women will reach screening age and there is an urgency to define the best screening practices among vaccinated women. Cancer risk will be significantly reduced in vaccinated women, and modelling studies have shown that the screening interval can be significantly lengthened among them. If screening programmes are not changed for vaccinated women – the number of unnecessary referrals will likely increase, leading to unnecessary costs.
Two studies will be implemented to evaluate screening strategies in vaccinated women.
In the first study, an already existing large cohort from a community-randomized HPV vaccination trial from Finland will be used. This vaccination trial was already started in 2007 and covers a large part of the entire adolescent population of Finland. The vaccinated birth cohorts are now entering screening ages. The current trial will evaluate whether considerably less-frequent cytological screening is cost-effective and yields the lowest disease burden and the highest quality of life for vaccinated women.
Women who were vaccinated (and screened) at the age of 18-year will be individually re-randomized into three arms for the current study:
- Arm 1: screening at the age of 22, 25 and 30 years (7,000 women)
- Arm 2: screening at the age of 30 years only (at least 7,000 women)
- Arm 3: screening at the age of 25, 30 years (1,000 women)
Safety of the trial setting is guaranteed by sampling all participants on every visit, and referring the study participants to diagnosis and treatment pertinent to the cytological results according to local standard of care, and further by a safety interim analysis.
In the second study, women aged 22-23 years will be randomized to be vaccinated or not at age 22/23 years and will be screened 2 years later in the framework of national screening programmes. Vaccinated women will enrol in HPV-based screening with HPV16/18 genotyping and unvaccinated women will enrol in cytology screening. The aims of the study are to verify if:
- vaccination 2 years in advance increases the proportion of HPV positive women with a (pre) cancerous lesion (and reducing unnecessary referral and anxiety)a vaccination plus screening approach reaches similar or higher positive predictive value than conventional cytology (PAP smear) in unvaccinated women, therefore yielding a reduction of both human and financial costs
The second study will be implemented in Sweden and Italy.