The World Health Organization (WHO) has called for organized global action to eliminate cervical cancer as a public health threat, largely through increased vaccination for human papillomavirus (HPV). A modelling study, published in The Lancet, shows just how effective ramp-up of vaccination could be by 2069.
Data for the model were taken from cancer registries including the Cancer Incidence in Five Continents series from the International Agency for Research for Cancer. The authors assumed 100% efficacy of HPV vaccination against new infections and vaccination in men and women up to age 26. To predict incidence rates, they assumed that the population structure would remain unchanged from what it was worldwide in 2015. They then created a model to examine outcomes, given different scenarios for cervical screening and vaccination coverage.
With no further intervention, the authors project that there will be 44.4 million cervical cancer cases diagnosed globally between 2020 and 2069. The majority (approximately two-thirds) of these cases will occur in countries with low and medium Human Development Index (HDI) scores.
The model showed that 6.7 to 7.7 million cervical cancer cases could be averted if rapid, broad-spectrum HPV vaccination were implemented and global coverage increases up to 80% to 100% by 2020.
Implementing HPV-screening twice per lifetime (at ages 35 and 45) in all low- and middle-income countries with 70% coverage globally would boost the effects of prevention and avert approximately 12.5 to 13.4 million cases of cervical cancer. Combining rapid vaccination with screening would reduce the average number of annual cervical cancer cases to less than six per 100,000 by 2045 to 2049 for very-high-HDI countries, by 2055-2059 for high-HDI-countries, by 2065-2069 for medium-HDI-countries, and by 2085-2089 for low-HDI-countries.
The biggest takeaway from their study, the authors said, is that over 44 million women will be diagnosed with cervical cancer in the next 50 years if primary and secondary prevention programs are not implemented in low- and middle-income countries and vaccination rates and cancer screening do not improve. To reduce that number, both screening and vaccination should be increased. Scaling up screening will help reduce the short-term impact of cervical cancer while expansion of vaccination can help reduce the long-term impact.