Reducing cancer risk: the well-established basics

What the evidence supports

The World Health Organization (WHO) lists the following ways to reduce cancer risk (WHO cancer fact sheet):

• Avoid tobacco - the leading preventable cause of cancer. The US National Institutes of Health (NIH) states that tobacco use, primarily smoking, is the leading preventable cause of cancer and of death from cancer (NIH: Tobacco), and the US Centers for Disease Control and Prevention (CDC) uses the same wording (CDC Vital Signs: Cancer and Tobacco Use). WHO puts not using tobacco first in its list of ways to reduce cancer risk. The US National Cancer Institute (NCI) says there is no safe level of tobacco use, that secondhand smoke also raises risk, and that tobacco smoke contains many chemicals that damage DNA (NCI: Tobacco). NCI adds that quitting lowers the risk of developing and dying from cancer, and that it is never too late to benefit.
• Avoid or reduce alcohol. WHO includes avoiding or cutting down on alcohol among its cancer risk-reduction measures.
• Protect your skin from ultraviolet (UV) radiation from the sun and from artificial tanning devices such as sunbeds, and use sun protection.
• Keep a healthy body weight and do physical activity regularly.
• Eat a healthy diet, including fruit and vegetables. WHO's cancer research agency has classified processed meat as carcinogenic to humans (linked to bowel cancer) and red meat as probably carcinogenic, and many national dietary guidelines recommend limiting both (WHO Q&A on red and processed meat).
• Get vaccinated against HPV and hepatitis B if you belong to a group for which vaccination is recommended. WHO notes that some types of HPV raise the risk of cervical cancer and that hepatitis B and C raise the risk of liver cancer.
• Reduce exposure to air pollution, including indoor radon, a natural radioactive gas that can build up in buildings, and limit unnecessary exposure to radiation.

Screening and early detection

Screening is mainly about finding problems early rather than preventing them. WHO describes screening as looking for findings suggestive of a specific cancer or pre-cancer before symptoms develop, and notes it works for some cancer types but not all. Whether and when you should be screened depends on your age, history and country - see cancer screening explained and ask your doctor.

Two screening programmes link closely to the risks above. WHO says cervical cancer is largely preventable through HPV vaccination and regular screening (WHO: Cervical cancer fact sheet) - see what is a Pap smear? And for some people with a long smoking history, the US Preventive Services Task Force recommends yearly low-dose CT scans - see lung cancer screening. Screening does not replace quitting tobacco.

Factors you cannot change

NCI lists age and family history among the risk factors people cannot control. WHO notes that cancer becomes much more common with age. A family history of certain cancers can sometimes point to an inherited gene change; if that applies to you, read is cancer hereditary? and mention it to your doctor (NCI: Risk Factors for Cancer).

A note on headlines

NCI points out that a single study linking a food or habit to cancer cannot, on its own, prove cause and effect, and that such findings can create wrong ideas about cancer. Scientists become more confident when many studies point the same way. Be cautious with products or websites that claim to "prevent" or "cure" cancer.

Sources

• World Health Organization: Cancer fact sheet (Prevention)
• National Cancer Institute: Risk Factors for Cancer
• National Cancer Institute: Tobacco
• National Cancer Institute: Harms of Cigarette Smoking and Health Benefits of Quitting
• National Institutes of Health: Tobacco
• CDC Vital Signs: Cancer and Tobacco Use (archived page)
• World Health Organization: Carcinogenicity of red and processed meat
• World Health Organization: Cervical cancer fact sheet
• US Preventive Services Task Force: Lung Cancer Screening

Last reviewed: 21 October 2026.