Cancer Prevention

Mortality rates of cancer have begun to decrease in the past 2 years; part of this decrease results from reductions in tobacco use, since cigarette smoking is the most important preventable cause of cancer. Primary prevention of skin cancer consists of restricting exposure to ultraviolet light by wearing appropriate clothing and use of sunscreens. In the past 2 decades, there has been a threefold increase in the incidence of squamous cell carcinoma and a fourfold
increase in melanoma in the United States. Persons who engage in regular physical exercise and avoid obesity have lower rates of breast and colon cancer. Prevention of occupationally induced cancers involves minimizing exposure to carcinogenic substances such as asbestos, ionizing radiation, and benzene compounds. Chemoprevention has been widely studied for primary cancer prevention, but large trials in women taking aspirin, vitamin E, or calcium and vitamin D did not find reductions in cancer incidence or mortality. Use of tamoxifen, raloxifene, and aromatase inhibitors for breast cancer prevention. Hepatitis B vaccination can prevent hepatocellular carcinoma, and the development of an HPV vaccine holds promise for prevention of cervical cancer.