Chapter 004. Screening and Prevention of Disease (Kỳ 4) a Screening is performed earlier and more frequently when there is a strong family history. Randomized, controlled trials have documented that fecal occult blood testing (FOBT) confers a 15 to 30% red uction in colon cancer mortality. Although randomized trials have not been performed for sigmoidoscopy or colonoscopy, well-designed case- control studies suggest similar or greater efficacy relative to FOBT. b In the future, Pap smear frequency may be influ enced by HPV testing and the HPV vaccine. Note: Prostate- specific antigen (PSA) testing is capable of enhancing the detection of early- stage prostate cancer, but evidence is inconclusive that it improves health outcomes. PSA testing is recommended by sever al professional organizations and is widely used in clinical practice, but it is not currently recommended by the U.S. Preventive Services Task Force (Chap. 81). Source: Adapted from the U.S. Preventive Services Task Force, 2005. Guide to Clinical Prevention Services , 3d ed. http://www.ahrq.gov/clinic/uspstfix.htm Cost-Effectiveness Screening techniques must be cost-effective if they are to be applied to large populations. Costs include not only the expense of testing but also time away from work and potential risks. When the risk-to-benefit ratio is less favorable, it is useful to provide information to patients and factor their perspectives into the decision-making process. For example, many expert groups, including the USPSTF, recommend an individualized discussion about prostate cancer screening, as the decision-making process is complex and relies heavily on personal issues. Although the early detection of prostate cancer may intuitively seem desirable, risks include false-positive results that can lead to anxiety and unnecessary surgery. Potential complications from surgery and radiation treatment include erectile dysfunction, urinary incontinence, and bowel dysfunction. Some men may decline screening, while others may be more willing to accept the risks of an early-detection strategy. Another example of shared decision-making is the choice of colon cancer screening techniques (Chap. 78). In controlled studies, the use of annual FOBT reduces colon cancer deaths by 15–30%. Flexible sigmoidoscopy reduces colon cancer deaths by ~60%. Colonoscopy offers the same, or greater, benefit than flexible sigmoidoscopy, but its use incurs additional costs and risks. These screening procedures have not been directly compared in the same population, but the estimated cost to society is similar: $10,000–25,000 per year of life saved. Thus, while one patient may prefer the ease of preparation, less time disruption, and the lower risk of flexible sigmoidoscopy, others may prefer the sedation and thoroughness of colonoscopy. When considering the impact of screening tests, it is important to recognize that tobacco and alcohol use, diet, and exercise comprise the vast majority of factors that influence preventable deaths in developed countries. Perhaps the single greatest preventive health care measure is to help patients quit smoking (Chap. 390). Commonly Encountered Issues Despite compelling evidence that prevention strategies can have major health care benefits, implementation of these services is challenging because of competing demands on physician and patient time and because of gaps in health care reimbursement. Moreover, efforts to reduce disease risk frequently involve behavior changes (e.g., weight loss, exercise, seatbelts) or managing addictive conditions (e.g., tobacco and alcohol use) that are often recalcitrant to intervention. Public education and economic incentives are often useful, in addition to counseling by health care providers (Table 4-4). Table 4-4 Counseling to Prevent Disease Topic Chapter Reference Tobacco cessation 390 Drug and alcohol use 387, 388 Nutrition to maintain caloric balance and vitamin intake 54 Calcium intake in women >18 years 318 Folic acid: Women of childbearing age 71 Oral health 24 Aspirin use to prevent cardiovascular disease in selected men >40 years and women >50 years 235 Chemoprevention of breast cancer in women at high risk 65 STDs and HIV prevention 124, 182 Physical activity Sun exposure 57 Injury prevention (loaded handgun, seat belts, bicycle helmet) Issues in the elderly 9 Polypharmacy Fall prevention Hot water heater <120° Vision, hearing, dental evaluations Immunizations (pneumococcal, influenza) Note: STDs, sexually transmitted diseases. . Chapter 004. Screening and Prevention of Disease (Kỳ 4) a Screening is performed earlier and more frequently when there is a strong family history. Randomized, controlled. that prevention strategies can have major health care benefits, implementation of these services is challenging because of competing demands on physician and patient time and because of gaps. thoroughness of colonoscopy. When considering the impact of screening tests, it is important to recognize that tobacco and alcohol use, diet, and exercise comprise the vast majority of factors