EU Science Hub

Epidemiology of bladder cancer in Europe

Abstract: 
The European Commission has recently extended its capability of connecting up research and policy conceiving at the Joint Research Centre in Ispra (Italy), with its recently established activity aimed at the set-up of an integrated and comprehensive cancer information system for Europe. The goal is to ease access and availability at European level of updated and reliable information on cancer burden – both for primary and recurrent cases, and on geographical patterns and temporal trends of incidence, mortality, prevalence and survival indicators, in order to drive health interventions and at a later stage enable evaluation of their effectiveness. To achieve the purpose a strong collaboration has been established between the JRC and the population-based cancer registries (CR) spread all over Europe, in their invaluable role of row data collectors; since 2013, the JRC is hosting the Secretariat of the European Network of Cancer Registries (ENCR), that is the scientific association embracing the over 150 European registries. In the European Union (EU-28), according to the estimates of the International Agency for Research on Cancer (IARC), bladder cancer ranks fifth among the most frequently diagnosed cancers with about 124,000 new cases predicted in 2012 for both sexes, representing around 5% of all the incident cases. Among men, with 97,000 new diagnoses estimated for 2012 bladder cancer represents around 7% of all new cancers cases, ranking fourth after prostate, lung, and colorectal cancers. Among women, it is the thirteenth most frequently diagnosed tumour, with 27,000 new cases per year, and representing around 2% of all new cancer cases. For 2015, the overall number of estimated new cases is about 131,000 (103,000 men and 28,000 women), and it is expected to grow up to 141,000 in 2020. Within the European Union there is a huge variability in incidence rates, either among men – going from the age-adjusted rate (on the World standard population, ASR) of 31.0 for Belgium to the lower level of 9.2 for UK , as well as for women – ranging from 7.4 for Hungary to 2.5 for Cyprus. The epidemiology of bladder cancer is strictly related to that of its main risk factor: smoking. Therefore, the temporal trend of age standardized incidence rates has followed the changes in the prevalence of smokers of the populations. Indeed, in many countries there was a long standing increasing tendency (especially among men) in the past years, followed by a more recent decrease and/or a flattening of trends. As regards cancer mortality, in European Union bladder cancer represents the ninth cause of death, with around 40,000 deaths (3% of all the total cancer deaths) estimated in 2012 and nearly 43,000 estimated for 2015. Mortality for bladder cancer decreases over time throughout in Europe among men, while it is stable or decreases among women. Approximately 324,000 EU-28 citizens are estimated with a bladder cancer diagnosis in the last five years (five-year prevalence); in other words, around 9% (around 3,700,000) of all European citizens alive with a previous (5-year) cancer diagnosis were having bladder cancer. They represent the burden for clinical follow-up and assistance for the European urologists and the EU-28 health systems. As regards survival measures, the Eurocare project has compared cancer survival data among European countries since decades, and currently its 6th edition benefits from a fruitful collaboration and coordination with the ENCR-JRC project. The most recent data of the Eurocare project (Eurocare-5) showed that the 5-year relative survival for bladder cancers diagnosed in 2000-2007 is on average around 69% (Marcos-Gracera et al. Eur J Cancer 2015), varying from 75% in Northern to 65% in Eastern Europe. Some of the differences are presumably related to the stage at diagnosis. In fact, after one year since diagnosis the probability to survive additional 5 years not only improves substantially – it is on average 81%, but also geographical differences decrease from 85% in Southern to 80% in Central Europe, because the death of more advanced cases made the case series more homogeneous. Finally, and differently from many other tumors, bladder cancer survival is higher for men (European age-standardized 5-year relative survival 69%) than for women (66%). Bladder cancer registration represents a challenge for CR staff due to its complex biology that includes both non-invasive and invasive tumors, the use of different grade and stage definitions; moreover, this cancer is typically characterized by multifocal onsets and recurrences. Therefore, comparable and reliable information at EU-28 level implies availability and correct application of common classifications and rules, in order to to assure throughout the collection of data on equivalent lesions. Indeed, the inclusion or exclusion of non-invasive papillary or flat tumors may sensibly affect either incidence and survival estimates, making comparisons unreliable, and actually ENCR recommendations to European cancer registries claim for a full registration (all histological type and stages) of bladder tumors. In this action of support and harmonization to registries the ongoing collaboration between the Joint Research Centre and the European Network of Cancer Registries is vital as well as good coordination with urologists and oncologists, to translate all those relevant scientific innovations possibly affecting data collection.