There were attempts to link various cancer-related risk factors to one another. It is estimated that 43 per cent of all new cancer cases could be avoided by modifying the risk factors for cancer that individuals can affect through their own actions. Smoking is the largest single cause, accounting for up to 20 per cent of all new cases of cancer. It should be noted that the influence of the different population-level variables would vary depending on regional conditions and population health and socio-economic behavior.

Categorizing Risk factors of Cancer

Cancer risk factors can be roughly divided into the following categories:

• Internal factors, such as age, sex, metabolism of substances foreign to the body, inherited genetic defects and non-inherited gene disorders, as well as the type of skin.
• Lifestyle-related factors,
• Occupational exposures, e.g., many chemicals, radioactive materials and asbestos,
• Environmental exposure, e.g., radon and UV radiation, as well as small particles.

Key points

• The majority of cancers are related to ageing. The longer a person lives, the more likely it is that these cells develop cancer that causes lesions.
• It is projected that by adjusting the risk factors that people can affect, more than 40 per cent of all new cancer cases may be prevented.
• Tobacco is the single largest risk factor, accounting for up to 20 per cent of all new cancer cases.
• Cancer is a complex disease that develops over time as healthy cells undergo genetic changes, transforming into abnormal tissue that grows independently. The causes, development, symptoms, and treatment of cancer can vary widely between different types of cancer.
• The creation of most cancers includes human factors related to behavior and living conditions. While individual susceptibility can be a factor associated with some cancers, for a cancer to develop, external factors are necessary almost always.