1-08: Cancer Prevention

PRIMARY PREVENTION

Cancer mortality rates continue to decrease in the United States; 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. 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 (see earlier Chemoprevention section and Chapter 39). Use of tamoxifen, raloxifene, and aromatase inhibitors for breast cancer prevention is discussed in Chapters 17 and 39. Hepatitis B vaccination can prevent hepatocellular carcinoma (HCC). Screening and treatment of hepatitis C is another strategy to prevent HCC (see Chapter 16); new recommendations have extended the population eligible for screening. The use of HPV vaccine to prevent cervical and possibly anal cancer is discussed earlier in this chapter. HPV vaccines may also have a role in the prevention of HPV-related head and neck cancers. The USPSTF recommends genetic counseling and, if indicated after counseling, genetic testing for women whose family or personal history is associated with an increased risk of harmful mutations in the BRCA 1/2 gene. Guidelines for optimal cancer screening in adults over the age of 75 are unsettled; thus, an individualized approach that considers differences in disease risk rather than chronological age alone is recommended.

SCREENING & EARLY DETECTION

Screening prevents death from cancers of the breast, colon, and cervix. Current cancer screening recommendations from the USPSTF are available online at https://www.uspreventiveservicestaskforce.org/BrowseRec/Index/browse-recommendations. Despite an increase in rates of screening for breast, cervical, and colon cancer over the last decade, overall screening for these cancers is suboptimal. Interventions effective in promoting recommended cancer screening include group education, one-on-one education, patient reminders, reduction of structural barriers, reduction of out-of-pocket costs, and provider assessment and feedback. Multi-component interventions are generally more effective than single component ones.

Though breast cancer mortality is reduced with mammography screening, screening mammography has both benefits and downsides. Clinicians should discuss the risks and benefits with each patient and consider individual patient preferences when deciding when to begin screening (see Chapters 17 and e6).

Digital breast tomosynthesis (three-dimensional mammography) integrated with digital mammography increases cancer detection rates compared to digital mammography alone; however, the extent of improved detection and impact on assessment outcomes need further ...