Trends of cervical cancer mortality in the member states of the European Union
Introduction
According to recent estimates for the year 2004, approximately 34,300 women in the European Union (EU) developed cervical cancer and about 16,300 died from the disease.1 The main etiologic factor for cervical cancer is persistent infection with sexually transmittable high-risk human papillomaviruses.2 By well organised screening and treatment of screen-detected high-grade cervical intraepithelial neoplasia (CIN) invasive cancer can be avoided.3 Therefore, trends in incidence of cervical cancer largely reflect coverage and quality of screening, as well as changes in exposure to risk factors which are mainly related to sexual habits of successive cohorts.4, 5
Mortality trends are determined by the incidence and case fatality rate. Survival (the complement of case fatality) is influenced by stage and age of diagnosis, and access to and effectiveness of cancer treatment.4, 5, 6, 7 Screening also plays a role in detecting invasive cancer at an early curable stage.8 The study of incidence trends would be more pertinent to assess the impact of cervical cancer screening. However, incidence data reported by cancer registries are less comprehensive than mortality statistics, which have been compiled from nearly all European countries for several decades by the World Health Organisation (WHO). Furthermore, cancer incidence statistics from early periods in certain registries are inflated by inclusion of pre-invasive lesions, and cancer registries often do not separate micro-invasive (easily curable) from fully invasive cancer cases (resulting in substantial mortality).9
Trend analyses of cervical cancer mortality are often hampered by inaccuracies in certification of cause of death, since, in many countries, a substantial fraction of uterine cancer deaths are coded as cancer from the uterus not otherwise specified (NOS) where it is not determined whether the cancer originated form the cervix or the corpus uteri.10, 11 Moreover, in the 8th International Codification of Diseases, cancer of the corpus uteri or of the uterus NOS were grouped in one 3-digit code. In a previous special issue dedicated to cervical cancer screening in Europe, Levi et al. analysed the trend of mortality from cervical cancer in Europe.12 No attempt was made to correct for inaccuracies in the certification of death by uterine cancers. As a proxy for cervical cancer mortality, cancer of all uterus cancers combined was studied among women aged younger than 45 years, since in this age group the large majority of uterine cancers originate from the cervix.13 However, this age group may not enable assessment of the full population impact of screening, as the majority of deaths from cervix cancer occur after the age of 45 years. In the current study, an algorithm was developed to reallocate deaths from the uterus NOS or combined groups, building further on previously published methods.10, 11 Finally, the trends of the corrected rates are tentatively explained as a result of secondary prevention taking into account changes in exposure to risk factors and the impact of oncologic treatment on survival.
Section snippets
Source of data
Data on number of deaths from uterine cancers and the size of the female population, aggregated by calendar year, 5-year age group (with the last category being ⩾85 years) and country (current member states of the EU) was obtained from the WHO mortality database (http://www.who.int/whosis/mort/download/en/). We distinguished the 15 old (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Portugal, Spain, Sweden, The Netherlands and the United Kingdom) from
Results
Fig. 1 shows the joinpoint regression plots for the age-standardised cervical cancer mortality corrected according to the three reallocation rules for all countries. The Y-axis is scaled equally in all graphs facilitating visual interpretation and comparison. Table 2 identifies the joinpoints and the annual percentage of change in each linear segment.
In Eastern Europe, standardised trends were localised above those observed in most other parts of Europe. The trends were decreasing in the Czech
Discussion
The current trend analyses confirm previous reports revealing the large contrasts in the burden of cervical mortality between the old and new member states of the EU.1, 25 Moreover, our study indicates that these contrasts will increase in the future since mortality rates continue to decrease in the western part of Europe, whereas in Eastern Europe and in the Baltic states they are either decreasing at a lower intensity (Czech Republic, Poland), remaining constant at a high rate (Estonia,
Conflict of interest statement
None declared.
Acknowledgements
Financial support was received from (1) the European Commission (Directorate of SANCO, Luxembourg, Grand-Duchy of Luxembourg), through the European Network for Information on Cancer (IARC, Lyon, France) and through the EUROCHIP-3 Network (Istituto Nazionale dei Tumori, Milan, Italy); (2) IWT (Institute for the Promotion of Innovation by Science and Technology in Flanders, project number 060081); (3) National Cancer Plan, through the National Health Insurance Institute (Brussels, Belgium); (4)
References (42)
- et al.
Trends in mortality from cervical cancer in the Nordic countries: association with organised screening programmes
Lancet
(1987) - et al.
Recent trends of cancer in Europe: A combined approach of incidence, survival and mortality for 17 cancer sites since the 1990s
Eur J Cancer
(2008) - et al.
Sheep and goats: separating cervix and corpus uteri from imprecisely coded uterine cancer deaths, for studies of geographical and temporal variations in mortality
Eur J Cancer
(2004) - et al.
Cervical cancer mortality among young women in Europe: patterns and trends
Eur J Cancer
(2000) Cancer of the cervix: a sexually transmitted infection?
Lancet
(1974)- et al.
Burden of cervical cancer in Europe: estimates for 2004
Ann Oncol
(2007) - et al.
Cervical cancer mortality is increasing in Spanish women younger than 50
Cancer Letters
(2006) - et al.
Cancer burden in the year 2000. The global picture
Eur J Cancer
(2001) - et al.
HPV infection in Europe
Eur J Cancer
(2009) - et al.
The challenges of organising cervical screening programmes in the 15 old member states of the European Union
Eur J Cancer
(2009)