Towards primary HPV screening in New Zealand: a service evaluation project

Over the next 12 months the Ministry of Health will be collaborating on an Australian initiative, led by the University of New South Wales and Victorian Cytology Service, to trial human papillomavirus (HPV) testing as the primary cervical screening test in place of cytology (cervical smear). 

The project will be undertaken in the Auckland region and will align with the testing technologies used in the Australian trial. The project is intending to recruit about 500 eligible women (25-64 years) presenting for routine cervical smears, from local primary care practices. Only women who are willing and able to provide informed consent will participate. The project will incorporate genotyping HPV 16/18 (+/-45) and dual stained cytology with p16/Ki67 to assist with the management of HPV positive women.

Many other countries are currently introducing or piloting primary HPV screening. This approach is also recommended for all countries by the World Health Organisation (International Agency for Research on Cancer).
A change in screening policy (from cytology screening to HPV screening) may become necessary over the medium term because of HPV immunisation.

As HPV immunised women reach screening age, the effectiveness of cytology as a screening test declines (cytology is less sensitive in immunised women), however screening will continue to be essential as not all HPV types are covered by the vaccine. The risk of the cervical screening programme failing to detect cases of pre-cancer may therefore increase, even if high coverage with HPV vaccine is achieved.

By contrast, HPV testing is considered to be more sensitive than cytology in HPV immunised women, decreasing the risk of false negative screens (missing an abnormal result).

Replacing cytology with HPV testing as the primary screening test could also reduce the number of women referred to colposcopy and may allow the screening interval to be increased from 3 to 5 years.

The Ministry of Health has also commissioned a modelling study to evaluate the cost effectiveness of various screening strategies in New Zealand involving HPV as the primary screening test. This modelling work will help determine the optimal age range for cervical screening as well as the optimal interval of screening in the New Zealand context, which will take into account predicted immunisation coverage and screening rates.

Both pieces of work will help to inform any proposed policy change to the existing NCSP, within the next 5 years. Depending on the outcomes of this work, the Ministry may proceed to develop options for a national rollout of primary HPV screening, in consultation with all stakeholders.