Data and statistics
Cancer is the uncontrolled growth and spread of cells that arises from a change in one single cell. The change may be started by external agents and inherited genetic factors and can affect almost any part of the body. The transformation from a normal cell into a tumour cell is a multistage process where growths often invade surrounding tissue and can metastasize to distant sites. These changes result from the interaction between a person's genetic factors and any of three categories of external agents:
- physical carcinogens, such as ultraviolet and ionizing radiation or asbestos;
- chemical carcinogens, such as vinyl chloride, or betnapthylamine (both rated by the International Agency for Research into Cancer as carcinogenic), components of tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking-water contaminant); and
- biological carcinogens, such as infections from certain viruses, bacteria or parasites.
Most chemicals to which people are exposed in everyday life have not been tested for their long-term impact on human health.
Many cancers can be prevented by avoiding exposure to common risk factors, such as tobacco smoke. In addition, a significant proportion of cancers can be cured, by surgery, radiotherapy or chemotherapy, especially if they are detected early.
Quick facts and figures
- Tobacco consumption and excessive alcohol consumption cause about 40% of the total cancer burden. The precise figures vary from country to country.
- If the consequences of inappropriate diet, obesity and insufficient physical activity are added, the percentage of cancers due to an unhealthy lifestyle rises to 60%.
- Although more than 40% of cancer deaths can be prevented, cancer is a leading cause of death, causing 20% of the total in the European Region.
- With more than 3 million new cases and 1.7 million deaths each year, cancer represents the second most important cause of death and morbidity in Europe. On a global scale, cancer accounted for 7.4 million deaths (around 13% of the total) in 2004.
- Europe comprises only one eighth of the total world population but has around one quarter of the global total of cancer cases: some 3.2 million new patients per year.
- Lung, stomach, liver, colon and breast cancer cause the most cancer deaths each year.
- Tobacco use is the single most important risk factor for cancer.
- The STEPwise Approach to Chronic Disease Risk Factor Surveillance was developed by WHO to promote the use of standardized methods and tools. It enables countries to strengthen their capacity to collect the core data required for policy and programme development, implementation and evaluation. The approach has been undertaken in low- and middle income countries throughout the world.
- The WHO Global InfoBase is an online tool created to improve access by public-health professionals to country-level data on chronic diseases and risk factors. It brings together survey data collected from all WHO Member States and provides users with full traceability and access to survey methods.