A comparative modelling analysis in 78 low-income and lower-middle-income countries (LMICs) suggest that high human papillomavirus (HPV) vaccination coverage of girls can lead to cervical cancer elimination in most LMICs by the end of the century. Screening with high uptake will expedite reductions and will be necessary to eliminate cervical cancer in countries with the highest burden. The findings are published online on 30 January 2020 in The Lancet.
In May 2018, Director-General of the World Health Organization (WHO) has issued a call for action to eliminate cervical cancer as a public health problem. To help inform global efforts, the experts from the WHO Cervical Cancer Elimination Modelling Consortium (CCEMC), modelled potential HPV vaccination and cervical screening scenarios in LMICs to examine the feasibility and timing of elimination at different thresholds, and to estimate the number of cervical cancer cases averted on the path to elimination.
The WHO CCEMC, which consists of three independent transmission-dynamic models identified by WHO according to predefined criteria, projected reductions in cervical cancer incidence over time in 78 LMICs for three standardised base-case scenarios: girls-only vaccination; girls-only vaccination and once-lifetime screening; and girls-only vaccination and twice-lifetime screening.
Girls were vaccinated at age 9 years with a catch-up to age 14 years, assuming 90% coverage and 100% lifetime protection against HPV types 16, 18, 31, 33, 45, 52, and 58. Cervical screening involved HPV testing once or twice per lifetime at ages 35 years and 45 years, with uptake increasing from 45% in 2023 to 90% from 2045 onwards.
The elimination thresholds examined were an average age-standardised cervical cancer incidence of four or fewer cases per 100 000 women-years and ten or fewer cases per 100 000 women-years, and an 85% or greater reduction in incidence. Sensitivity analyses were done, varying vaccination and screening strategies and assumptions. The study team summarised results using the median (range) of model predictions.
Girls-only HPV vaccination was predicted to reduce the median age-standardised cervical cancer incidence in LMICs from 19.8 (range 19.4–19.8) to 2.1 (2.0–2.6) cases per 100 000 women-years over the next century (89.4% [86.2–90.1] reduction), and to avert 61 million (60.5–63.0) cases during this period. Adding twice-lifetime screening reduced the incidence to 0.7 (0.6–1.6) cases per 100 000 women-years (96.7% [91.3–96.7] reduction) and averted an extra 12.1 million (9.5–13.7) cases.
Girls-only vaccination was predicted to result in elimination in 60% (58–65) of LMICs based on the threshold of four or fewer cases per 100 000 women-years, in 99% (89–100) of LMICs based on the threshold of ten or fewer cases per 100 000 women-years, and in 87% (37–99) of LMICs based on the 85% or greater reduction threshold. When adding twice-lifetime screening, 100% (71–100) of LMICs reached elimination for all three thresholds.
In regions in which all countries can achieve cervical cancer elimination with girls-only vaccination, elimination could occur between 2059 and 2102, depending on the threshold and region. Introducing twice-lifetime screening accelerated elimination by 11–31 years. Long-term vaccine protection was required for elimination.
The authors concluded that their comparative modelling analysis suggests that cervical cancer elimination as a public health problem is possible by the end of the century in LMICs. To achieve elimination across all LMICs under the proposed threshold, four or fewer cases per 100 000 women-years, both high HPV vaccination coverage and screening uptake will be necessary, particularly in countries with the highest burden.
Considerable international commitment will be required to achieve WHO’s triple-intervention targets (intensive scale-up of girls only HPV vaccination, twice-lifetime screening, and treatment of cancer and precancers), particularly in countries with the highest burden of cervical cancer, where scale-up of vaccination and screening resources are most urgently needed. These results are being used by WHO to inform its global strategy to accelerate cervical cancer elimination, which will be presented at the World Health Assembly in May 2020.
The study was funded by WHO, UNDP, UN Population Fund, UNICEF–WHO–World Bank Special Program of Research, Development and Research Training in Human Reproduction, Canadian Institute of Health Research, Fonds de recherche du Québec–Santé, Compute Canada, National Health and Medical Research Council Australia Centre for Research Excellence in Cervical Cancer Control.
Brisson M, Kim JJ, Canfell K, et al. Impact of HPV vaccination and cervical screening on cervical cancer elimination: a comparative modelling analysis in 78 low-income and lower-middle-income countries. The Lancet; Published online 30 January 2020. DOI: https://doi.org/10.1016/S0140-6736(20)30068-4.