The combined impact of implementing HPV immunisation and primary HPV screening in New Zealand: Transitional and long-term benefits, costs and resource utilisation implications.

BACKGROUND

In response to emergent evidence, many countries are transitioning from cytology-based to HPV screening. We evaluated the impact of an upcoming transition on health outcomes and resource utilisation in New Zealand.

METHODS

An extensively validated model of HPV transmission, vaccination, natural history and cervical screening ('Policy1-Cervix') was utilised to simulate a transition from three-yearly cytology for women 20-69 years to five-yearly HPV screening with 16/18 genotyping for women 25-69 years, accounting for population growth and the impact of HPV immunisation. Cervical cancer rates, resources use (test volumes), costs, and test positivity rates from 2015 to 2035 were estimated.

FINDINGS

By 2035, the transition to HPV screening will result in declines in cervical cancer incidence and mortality rates by 32% and 25%, respectively, compared to 2018. A potentially detectable 5% increase in cervical cancer incidence due to earlier detection is predicted for the year of transition. Annual numbers of women screened will fluctuate with the five-year screening interval. Cytology volumes will reduce by over 80% but colposcopy volumes will be similar to pre-transition rates, and program costs will be reduced by 16%. A 9% HPV test positivity rate is expected in the first round of HPV screening (2019-2023), with 2.7% of women referred for colposcopy. Transitioning from cytology to primary HPV cervical screening could avert 149 cancer cases and 45 deaths by 2035.

CONCLUSION

Primary HPV screening and vaccination will reduce cervical cancer and resources use. A small transient apparent increase of invasive cancer rates due to earlier detection may be detectable at the population level, reflecting the introduction of a more sensitive screening test. These findings can be used to inform health services planning and public communications surrounding program implementation.