Population-based registry
The new data come from a population-based cancer registry that shows the incidence of cervical cancer and noninvasive cervical carcinoma (CIN3) in England between January 2006 and June 2019.
The study included seven cohorts of women who were aged 20-64 years at the end of 2019. Three of these cohorts composed the vaccinated population.
The team reports that overall, from January 2006 to June 2019, there were 27,946 cases of cervical cancer and 318,058 cases of CIN3.
In the three vaccinated cohorts, there were around 450 fewer cases of cervical cancer and 17,200 fewer cases of CIN3 than would be expected in a nonvaccinated population.
The three vaccinated cohorts had been eligible to receive Cervarix when they were aged 12-13 years. A catch-up scheme aimed at 14- to 16-year-olds and 16- to 18-year-olds. Most of these persons were vaccinated through a school vaccination program.
The team analyzed the data for each of these cohorts.
Among the cohort eligible for vaccination at 12-13 years of age, 89% received at least one dose of the HPV vaccine; 85% received three shots and were fully vaccinated. Among these persons, the rate of cervical cancer was 87% lower than expected in a nonvaccinated population, and the rate of CIN3 was 97% lower than expected.
For the cohort that was eligible to be vaccinated between the ages of 14 and 16 years, the corresponding reductions were 62% for cervical cancer and 75% for CIN3.
For the cohort eligible for vaccination between the ages of 16 and 18 years (of whom 60% had received at least one dose and 45% were fully vaccinated), the corresponding reduction were 34% for cervical cancer and 39% for CIN3.
The authors acknowledge some limitations with the study, principally that cervical cancer is rare in young women, and these vaccinated populations are still young. The youngest would have been vaccinated at age 12 in 2008 and so would be only 23 years old in 2019, when the follow-up in this current study ended. The authors emphasize that because the vaccinated populations are still young, it is too early to assess the full impact of HPV vaccination on cervical cancer rates.
Editorial commentary
“The relative reductions in cervical cancer, expected as a result of the HPV vaccination program, support the anticipated vaccine effectiveness,” commented two authors of an accompanying editorial, Maggie Cruickshank, MD, University of Aberdeen (Scotland), and Mihaela Grigore, MD, University of Medicine and Pharmacy, Lasi, Romania.
“The scale of the HPV vaccination effect reported by this study should also stimulate vaccination programs in low-income and middle-income countries where the problem of cervical cancer is a far greater public health issue than in those with well established systems of vaccination and screening,” they comment.
“The most important issue, besides the availability of the vaccine ... is the education of the population to accept the vaccination because a high rate of immunization is a key element of success,” they emphasize. “Even in a wealthy country, such as England with free access to HPV immunization, uptake has not reached the 90% vaccination target of girls aged 15 years set by WHO [World Health Organization].”
The authors and editorialists disclosed no relevant financial relationships. Dr. Markman is a regular contributor to Medscape Oncology. He has received income of $250 or more from Genentech, AstraZeneca, Celgene, Clovis, and Amgen.
A version of this article first appeared on Medscape.com.