HPV-vaccination offers good protection against HPV-16/18 related high-grade cervical lesions in women vaccinated before sexual debut. In Denmark, vaccination of girls started with those born in 1993, and 80% received at least one dose. These women are about to enter screening age starting at 23 years in Denmark. The challenge now is to optimise screening for these women.
We combined screening data for a previous generation of unvaccinated women with data from vaccination trials (1) to estimate the expected screening outcome for vaccinated women (2). We furthermore searched the literature for data on expected outcome of various screening scenarios.
In the unvaccinated generation screened at age 23 years, 8.7% had ASCUS+ and 1.5% had CIN2+. In women vaccinated as girls these percentages were expected to decrease to 6.4% and 1.0%, respectively (2). On this background, we decided to undertake a public health trial where women turning 23 years will be randomised. The control arm will be the present screening programme with cytology testing every third year. The intervention arm will be primary HPV-testing; those testing negative will be reinvited after 6 years; those testing positive will have cytology triage. HPV+/cytology+ women will be followed up according to current guidelines in the Danish cytology-based screening programme. HPV+/cytology- women will be reinvited after 3 years.
Our expectation is that the intervention screening will provide HPV-vaccinated women with at least the same protection against CIN3+ as the present cytology screening; their burden of attending screening will be reduced; and the health care costs will be reduced.
(1) Munoz N, Kjaer SK, Sigurdsson K, Iversen OE, Hernandez-Avila M, Wheeler CM, et al. Impact of human papillomavirus (HPV)-6/11/16/18 vaccine on all HPV-associated genital diseases in young women. J Natl Cancer Inst 2010; 102:325-39.
(2) Hestbeck MS, Lynge E, Kragstrup J, Siersma V, Vazquez-Prada Baillet M, Brodersen J. HPV- vaccination and future cervical screening: The interplay between primary and secondary prophylaxis in primary care. BMJ Open. 2015 Aug 14;5(8):e007921. doi: 10.1136/bmjopen-2015-007921.