Methods of Measuring Health Benefits It is not practical to perform all possible screening procedures. For example, screening for laryngeal cancer in smokers is not currently recommended. It is necessary to examine the strength of evidence in favor of screening measures relative to the cost and risk of false-positive tests. For example, should ultrasound be used to screen for ovarian cancer in average-risk women? It is currently estimated that the unnecessary laparotomies triggered by finding benign ovarian masses would actually cause more harm than the benefit derived from detecting the occasional curable ovarian cancer. . | Chapter 004. Screening and Prevention of Disease Ky 2 Methods of Measuring Health Benefits It is not practical to perform all possible screening procedures. For example screening for laryngeal cancer in smokers is not currently recommended. It is necessary to examine the strength of evidence in favor of screening measures relative to the cost and risk of false-positive tests. For example should ultrasound be used to screen for ovarian cancer in average-risk women It is currently estimated that the unnecessary laparotomies triggered by finding benign ovarian masses would actually cause more harm than the benefit derived from detecting the occasional curable ovarian cancer. A variety of endpoints are used to assess the potential gain from screening and prevention interventions 1. The number of subjects screened to alter the outcome in one individual. It is estimated for example that 731 women ages 65-69 would need to be screened by dual-energy x-ray absorptiometry DEXA and then treated appropriately to prevent one hip fracture from osteoporosis. 2. The absolute and relative impact of screening on disease outcome. A meta-analysis of Swedish mammography trials ages 40-70 found that fewer women per thousand would die from breast cancer if they were screened over a 12-year period. By comparison 3 lives per 1000 might be saved from colon cancer in a population ages 50-75 screened with annual FOBT over a 13-year period. Based on this analysis colon cancer screening may actually save more women s lives than mammography. The impact of FOBT 1000 versus 1000 might be stated either as 3 lives per 1000 or as a 30 reduction in colon cancer death thus it is important to consider both the relative and absolute impact on numbers of lives saved. 3. The cost per year of life saved is used to assess the effectiveness of many screening and prevention strategies. Typically strategies that cost 30 00050 000 per year of life saved are considered cost-effective Chap. 3 . For .
