Human papillomavirus vaccination is changing the epidemiology of high-grade cervical lesions in Australia Julia M. L. Brotherton, A. Marion Saville, Cathryn L. May, Genevieve Chappell & Dorota M. Gertig Cancer Causes & Control An International Journal of Studies of Cancer in Human Populations ISSN 0957-5243 Volume 26 Number 6 Cancer Causes Control (2015) 26:953-954 DOI 10.1007/s10552-015-0568-6
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Author's personal copy Cancer Causes Control (2015) 26:953–954 DOI 10.1007/s10552-015-0568-6
LETTER TO THE EDITOR
Human papillomavirus vaccination is changing the epidemiology of high-grade cervical lesions in Australia Julia M. L. Brotherton1 • A. Marion Saville1 • Cathryn L. May1 Genevieve Chappell1 • Dorota M. Gertig1
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Received: 29 October 2014 / Accepted: 18 March 2015 / Published online: 25 March 2015 Ó Springer International Publishing Switzerland 2015
Dear Editor, In 2011, we reported the world’s first observation of a decline in high-grade cervical intra-epithelial neoplasia/ adenocarcinoma in situ (CIN) in a population following the implementation of a national human papillomavirus (HPV) vaccination program [1]. As measured using the population-based histopathology records held on the Victorian Cervical Cytology Registry, a dramatic decline was evident in very young women in Victoria, Australia, (aged \18 years) by the third year of Australia’s large-scale HPV vaccination program. Between 2007 and 2009, free vaccination was offered to women in the age range of 12–26 years using the quadrivalent HPV vaccine. Onequarter of Australia’s female population live in Victoria. Coverage achieved in the initial catch-up program was 83, 78, and 70 % for dose 1, 2, and 3 in 12- to 17-years-olds [2] and at least 55, 45, and 32 % in 18- to 26-year-old women (with some incomplete reporting of doses to the National HPV Vaccination Program Register) [3]. A subsequent retrospective cohort study, using data linked between the National HPV Vaccination Program Register and the Victorian Cervical Cytology Registry, confirmed that highgrade CIN is occurring at a lower rate in vaccinated than unvaccinated women [4], thus supporting the contention from the ecological level registry data that HPV vaccination was responsible for the observed decline in incidence in the post-vaccination period. Here, we report upon the changes in the prevalence of high-grade CIN in Victoria
& Julia M. L. Brotherton
[email protected] 1
Victorian Cytology Service Registries, Victorian Cytology Service, East Melbourne, VIC, Australia
that have occurred in the 7 years following the implementation of HPV vaccination. We extracted data from the Victorian Cervical Cytology Registry, as held on 20 May 2014, at which time the registry held 8,130,567 Pap test records for women screened between 2000 and 2013. Throughout this period, the recommended screening interval was every 2 years for women from the age of 18 years or 2 years after sexual activity, whichever was later. Histopathology records which included a report of high-grade CIN were identified for women aged \20, 20–24, 25–29, or 30 years and over at the time of diagnosis. High-grade cervical abnormalities (CIN) were defined as those including the histology-reporting categories of the National Cervical Screening Program HS03 and HE03. These include: high-grade squamous abnormality, CINII, CINIII, or CIN not otherwise specified; high-grade endocervical abnormality, endocervical dysplasia; and high-grade endocervical abnormality, adenocarcinoma in situ. Rates per year were calculated by age group as CIN per 1,000 women screened and plotted over time. Comparisons use Chi-squared tests. As shown in Fig. 1, substantial changes in the prevalence of high-grade CIN have occurred among young women in Victoria since HPV vaccination commenced in 2007. Rates of high-grade CIN are declining among young women, while continuing to slowly rise in older age groups. In women aged \20 years, rates have fallen from 10.9 per 1,000 screened women in 2006 (the year prior to vaccination) to 5.0 in 2013 (p \ 0.0001). In 2013, the rate in this age group was equal to the rate for women aged 30 and over (5.2 per 1,000, p = 0.9). Since 2009, rates in 20- to 24-year-old women (historically the age group with the highest rates) have also declined, with rates lower than those aged 25–29, and are falling year on year from a high of 21.5 per 1,000 screened women in 2008 (this peak
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Cancer Causes Control (2015) 26:953–954
Fig. 1 Trends in high-grade cervical abnormalities (histologically confirmed) by age group, 2000–2013, Victorian Cervical Cytology Registry (Data as held on 20 May 2014. The National HPV Vaccination Program commenced in April 2007)
coincided with the vaccination campaign and a marked increase in screening activity) to 13.5 in 2013 (p \ 0.0001). To summarize, these descriptive registry data support the contention that the quadrivalent HPV vaccination program has resulted in significant reductions in the incidence of screen-detected high-grade cervical lesions in young women in Australia. Although these data are subject to the limitations of ecological level data, they are time- and age group-specific trends and supported by data analyses linked to vaccination registry data which have shown that the vaccination is effective. Over time in Australia, the median age of sexual debut has fallen and the mean number of partners has risen, suggesting increasing rather than decreasing HPV exposure in younger cohorts over time. We expect these reductions in high-grade disease to continue as the youngest cohorts vaccinated at school commence screening. Australia is reviewing its National Cervical Screening Program, partly in response to the lower highgrade CIN prevalence environment in which screening will now operate. It is proposed that primary HPV testing, with partial genotyping and reflex cytology, will be used for screening from the age of 25 with an anticipated start date during 2017 [5].
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References 1. Brotherton JML, Fridman M, May C, Chappell G, Saville AM, Gertig DM (2011) Early effect of the HPV vaccination program on cervical abnormalities in Victoria, Australia: an ecological study. Lancet 377:2085–2092. doi:10.1016/S0140-6736(11)60551-5 2. Brotherton JML, Murray SL, Hall MA, Andrewartha LK, Banks CA, Meijer D, Pitcher HC, Scully MM, Molchanoff L (2013) Human papillomavirus vaccine coverage among female Australian adolescents: success of the school-based approach. Med J Aust 199:614–617. doi:10.5694/mja13.10272 3. Brotherton JML, Liu B, Donovan B, Kaldor JM, Saville M (2014) Human papillomavirus (HPV) vaccination coverage in young Australian women is higher than previously estimated: independent estimates from a nationally representative mobile phone survey. Vaccine 32:592–597. doi:10.1016/j.vaccine.2013.11.075 4. Gertig DM, Brotherton JML, Budd AC, Drennan K, Chappell G, Saville AM (2013) Impact of a population–based HPV vaccination program on cervical abnormalities: a data linkage study. BMC Med 11:227. doi:10.1186/1741-7015-11-227 5. Australian Government (2014) Medical Services Advisory Committee (MSAC) recommendations. Australian Government, Department of Health, National Cervical Screening Program http://www.cancerscreening.gov.au/internet/screening/publishing. nsf/Content/ncsp-renewal. Accessed 22 July 2014
