Prevention of Cancer

ByRobert Peter Gale, MD, PhD, DSC(hc), Imperial College London
Reviewed/Revised Sep 2022 | Modified Nov 2023

Although there are many different types of cancer, which have different causes and risk factors, doctors estimate that about 40% of cancers are preventable. Also, individual people have different risks for developing different cancers. Therefore, no set of prevention strategies is effective in every person. However, some general strategies do reduce the risk of cancer or cancer complications in many people. These general strategies fall into 3 categories:

  • Primary prevention: Steps people can take to lessen their chance of developing certain types of cancer

  • Secondary prevention: Directed at people who may already have some kind of cancer but have not developed symptoms

  • Tertiary prevention: Measures aimed at slowing down the effects of a cancer to prevent complications

Screening is part of secondary prevention of certain cancers. It involves using information about a person, particularly their risk factors for cancer and results of their physical examination, to guide testing to look for unrecognized cancer. Early detection of cancerous or precancerous growths can save lives. So it is important that people get recommended screening tests for cancer. For example, Papanicolaou (Pap) tests are a way to screen for cervical cancers by detecting precancerous changes in cells of the cervix. Colonoscopy is one of the screening tests for colorectal cancer. Removing precancerous colon polyps found during screening can decrease the chance of developing colorectal cancer.

Lifestyle factors

Lifestyle factors are the main reducible risk factors. The main factors include tobacco exposure, alcohol consumption, obesity, and preventable or avoidable infections (hepatitis B,hepatitis C, and-, human papilloma viruses). Reducing the risk of certain cancers may be possible through dietary and other lifestyle changes. How much risk can be reduced depends on the specific cancer.

Dietary changes reduce the risk of some types of cancer:

  • Decreasing alcohol intake can reduce the risk of head and neck, liver, and esophageal cancer.

  • Decreasing fat intake appears to reduce the risk of breast and colon cancers.

  • Limiting the intake of processed meat and increasing the intake of whole grains and fruits and vegetables may decrease risk of some types of cancer.

The way meat is cooked may also increase the risk of cancer. Grilling, broiling, or frying meats creates certain chemicals that have been linked to colon cancer. Using other cooking methods reduces the formation of these chemicals and may reduce the risk of colon cancer.

Tobacco use is directly associated with one third of all cancers. Not smoking and avoiding exposure to tobacco smoke can greatly reduce the risk of lung, kidney, bladder, head and neck, and several other cancer types. People who quit smoking can also reduce their risk of cancer, and the risks decrease over time. People who avoid the use of smokeless tobacco (snuff or chew) decrease their risk of cancer of the mouth and tongue. Current smokers or people who have smoked within the past 15 years are candidates for lung cancer screening.

Being overweight or obese increases cancer risk, especially breast cancer, colon cancer, endometrial cancer, esophageal cancer, kidney cancer and pancreatic cancer. People should try to maintain a healthy weight through both diet and exercise. Physical activity itself may reduce the risk of breast, endometrial, and prostate cancers.

Environmental factors

Carcinogens are substances that increase the risk of cancer. Some carcinogens, such as asbestos,benzene, and diesel engine exhaust may be present in the workplace, and workers in industries that use known carcinogens should take appropriate precautions to avoid or minimize exposure. Other carcinogens occur in the home or the environment. For example, radioactive elements that naturally occur in the earth decay into radioactive radon gas, which can collect inside the homes of people living in certain areas. Exposure to radon increases the risk of lung cancer, especially in people who smoke.

Avoiding sun exposure (especially during the middle of the day) can reduce the risk of skin cancers. Covering exposed skin and using sunscreens with a sun protection factor (SPF) of at least 30 that protect against both ultraviolet A and ultraviolet B light also help reduce the risk of skin cancer.

Vaccines against cancer

Vaccines can prevent certain types of cancer that are caused by viruses. For example, certain strains of sexually transmitted human papillomavirus (HPV) cause cervical cancer, anal cancer, and some forms of head and neck cancer. Vaccination against HPV before the first sexual encounter can largely prevent many cases of these cancers.

As another example, infection with hepatitis B virus increases the risk of liver cancer. Vaccination against hepatitis B virus can help prevent liver cancer.

Other factors

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. American Cancer Society: Information to help people reduce the risk of cancer

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