Reducing the risk of certain cancers may be possible through dietary (see Diet and Cancer) and other lifestyle changes. How risk can be reduced depends on the specific 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, and head and neck cancer. Avoiding the use of smokeless tobacco (snuff or chew) decreases the risk of cancer of the mouth and tongue.
Other lifestyle changes reduce the risk of several types of cancer. Decreasing alcohol intake can reduce the risk of head and neck, liver, and esophageal cancer. A reduced intake of fat in the diet appears to decrease the risk of breast and colon cancer. Avoiding sun exposure (especially during the middle of the day) can reduce the risk of skin cancer. Covering exposed skin and using sunscreen lotion with a sun protection factor (SPF) of at least 15 that protects against both ultraviolet A and ultraviolet B light also help reduce the risk of skin cancer. Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) reduces the risk of colorectal cancer. Papanicolaou (Pap) tests can help prevent cervical cancers by detecting precancerous changes in cells of the cervix.
Vaccination can prevent certain types of cancer that are caused by viruses. Cervical cancer is caused by infections with certain strains of sexually transmitted human papillomavirus (HPV). Vaccination against HPV before the first sexual encounter (see Human Papillomavirus Vaccine) can largely prevent cervical cancer. HPV infection also increases the risk of anal cancer and some forms of head and neck cancer. As another example, infection with hepatitis B virus increases the risk of liver cancer. Vaccination against hepatitis B virus can help prevent this type of cancer.
Early detection of cancerous or precancerous growths can save lives. For women 40 years of age or older, having yearly mammograms can help detect breast cancers while they are still curable. For people 50 years of age or older, having a colonoscopy (inspection of the large intestine through a flexible viewing tube) every few years can detect polyps and early cancers of the colon.