Overview: Causes of Cancer
The causes of cancer are not fully understood, but years of research have brought to light risk factors that increase people's chances of getting particular types of cancer. Some of these risk factors are inevitable, while others can be avoided by choosing to live a healthy lifestyle. For example, smoking cigarettes is an avoidable risk factor. Changing your lifestyle to get rid of unhealthy choices such as smoking can be difficult to accomplish (tobacco is an addictive drug and stopping smoking means beating that addiction), but the rewards are real. Stopping smoking and similar healthy lifestyle changes will not ensure that you never get cancer, but they will reduce your cancer risk. This is true whether you have never had cancer before, or if you have previously beaten cancer and are wondering what you can do to reduce your chances of relapse.
It is important to note that cancer is not a uniform illness, but rather has many forms. Each specific type of cancer is different and consequently has a different set of associated risk factors. Detailed information on specific risk factors for specific types of cancer are found in our cancer subtype documents.