Cervical cancer is the second most common cancer among women in lower- and middle-income countries, but universal human papillomavirus vaccination for girls would reduce new cervical cancer cases by about 90% over the next century, according to researchers.
Adding twice-lifetime cervical screening with human papillomavirus (HPV) testing would further reduce the incidence of cervical cancer, including in countries with the highest burden, the researchers reported in.
of Laval University, Quebec City, and colleagues conducted this study using three models identified by the World Health Organization. The models were used to project reductions in cervical cancer incidence for women in 78 low- and middle-income countries based on the following HPV vaccination and screening scenarios:
- Universal girls-only vaccination at age 9 years, assuming 90% of girls vaccinated and a vaccine that is perfectly effective
- Girls-only vaccination plus cervical screening with HPV testing at age 35 years
- Girls-only vaccination plus screening at ages 35 and 45.
All three scenarios modeled would result in the elimination of cervical cancer, Dr. Brisson and colleagues found. Elimination was defined as four or fewer new cases per 100,000 women-years.
The simplest scenario, universal girls-only vaccination, was predicted to reduce age-standardized cervical cancer incidence from 19.8 cases per 100,000 women-years to 2.1 cases per 100,000 women-years (89.4% reduction) by 2120. That amounts to about 61 million potential cases avoided, with elimination targets reached in 60% of the countries studied.
HPV vaccination plus one-time screening was predicted to reduce the incidence of cervical cancer to 1.0 case per 100,000 women-years (95.0% reduction), and HPV vaccination plus twice-lifetime screening was predicted to reduce the incidence to 0.7 cases per 100,000 women-years (96.7% reduction).
Dr. Brisson and colleagues reported that, for the countries with the highest burden of cervical cancer (more than 25 cases per 100,000 women-years), adding screening would be necessary to achieve elimination.
To meet the same targets across all 78 countries, “our models predict that scale-up of both girls-only HPV vaccination and twice-lifetime screening is necessary, with 90% HPV vaccination coverage, 90% screening uptake, and long-term protection against HPV types 16, 18, 31, 33, 45, 52, and 58,” the researchers wrote.
Dr. Brisson and colleagues claimed that a strength of this study is the modeling approach, which compared three models “that have been extensively peer reviewed and validated with postvaccination surveillance data.”
The researchers acknowledged, however, that their modeling could not account for variations in sexual behavior from country to country, and the study was not designed to anticipate behavioral or technological changes that could affect cervical cancer incidence in the decades to come.
The study was funded by the WHO, the United Nations, and the Canadian and Australian governments. The WHO contributed to the study design, data analysis and interpretation, and writing of the manuscript. Two study authors reported receiving indirect industry funding for a cervical screening trial in Australia.
SOURCE: Brisson M et al. Lancet. 2020 Jan 30.