Primary HPV testing: a proposal for co-testing in initial rounds of screening to optimise sensitivity of cervical cancer screening.

As explained by Kitchener in a previous issue of Cytopathology (2015;26:4-6), primary human papillomavirus (HPV) testing is likely to be introduced in the UK for all women aged 25-64 years following pilot site studies already in place. This will be necessary when the prevalence of cervical cancer and its precursors declines when vaccination takes effect but there is a risk in abandoning cytology as a primary test: a risk that would be most apparent in the present unvaccinated population in which the prevalence of cervical cancer and its precursors is exceptionally high. HPV testing is more sensitive than cytology but has a significant false-negative rate that could be detrimental to a successful screening programme if introduced without cytology backup. Accurate cytology would be needed for triage and could be compromised if HPV-negative tests were excluded from examination. This article proposes a compromise: cytology and HPV co-testing for the first two screening tests to optimise the sensitivity of the test as a whole. Registrations of invasive and in situ carcinoma of the uterine cervix in England indicate that the prevalence of the disease is highest in young women in the early rounds of screening. Calculations of the likely impact on the workload of this proposal have been based on a service evaluation of 295 cytology tests received at St Thomas' Hospital, which suggests that the volume of cytology tests would be reduced by approximately 60% compared with 80% for primary HPV testing alone. This proposal should be debated openly before irrevocable changes are made to a skilled workforce.