Byers T, Gorsky R
Division of Nutrition, Centers for Disease Control, Atlanta, Georgia 30333.
Cancer. 1992 Sep 1;70(5 Suppl):1288-95. doi: 10.1002/1097-0142(19920901)70:3+<1288::aid-cncr2820701515>3.0.co;2-1.
In many ways, colorectal cancer might be an excellent candidate for mass screening because of the following: (1) it is the second leading cause of cancer mortality in the United States; (2) it develops slowly from a precursor lesion; and (3) methods of early detection are available. Barriers to screening include unproven efficacy of the procedure and high costs.
Cost analyses are derived from two mathematic models that estimate screening costs and effects based on expert opinion and data from uncontrolled screening studies.
One screening option that follows the guidelines of the American Cancer Society and the National Cancer Institute (annual testing for occult fecal blood and sigmoidoscopy every 5 years) could result in a 40% decrease in colon cancer mortality for American adults between the ages of 50 and 75 years if they comply with screening. This model, developed by David Eddy, projects an average of 44 days of extra life per person screened, at a net cost of $57 per day of life gained. Using assumptions much less favorable to screening, the Office of Technology Assessment modeled this same screening strategy for those aged 65 years and older. This model predicted a similar benefit of extra life per person at a cost of $118 per day of life gained. This doubling of the predicted cost was caused by the inclusion of subsequent colonoscopic surveillance costs for those found to have polyps. Direct costs of screening annually for fecal occult blood and every 5 years by sigmoidoscopy would cost an average of approximately $48 per person per year for screening and follow-up testing of all positive results. Fecal occult blood testing alone, although less effective, costs only $20 per person per year, including follow-up testing of all positive findings.
The results from randomized trials of fecal occult blood screening will be known in the next 5 years, but trials of screening with sigmoidoscopy will not be complete for 10-15 years. Because mass screening programs will be difficult to fund without better data on their efficacy, colorectal cancer screening will continue to be a matter of individual decision making in the clinical setting for years to come. Clearer presentations of costs and benefits that can be understood by both patients and physicians are needed.
在许多方面，由于以下原因，结直肠癌可能是大规模筛查的理想对象：（1）它是美国癌症死亡的第二大主要原因；（2）它从前期病变缓慢发展而来；（3）有早期检测方法。筛查的障碍包括该程序未经证实的疗效和高成本。
成本分析源自两个数学模型，这些模型基于专家意见和非对照筛查研究的数据来估计筛查成本和效果。
一种遵循美国癌症协会和美国国立癌症研究所指南的筛查方案（每年检测潜血并每5年进行一次乙状结肠镜检查），如果50至75岁的美国成年人遵守筛查，可使结肠癌死亡率降低40%。由大卫·埃迪开发的这个模型预测，每筛查一人平均可延长44天寿命，每获得一天生命的净成本为57美元。技术评估办公室采用对筛查更为不利的假设，为65岁及以上人群模拟了相同的筛查策略。该模型预测每人有类似的额外寿命收益，每获得一天生命的成本为118美元。预测成本翻倍是因为对发现有息肉的人纳入了后续结肠镜监测成本。每年进行潜血筛查以及每5年进行一次乙状结肠镜检查的直接成本，包括对所有阳性结果的筛查和后续检测，每人每年平均约为48美元。仅进行潜血检测，尽管效果较差，但每人每年仅花费20美元，包括对所有阳性结果的后续检测。
潜血筛查的随机试验结果将在未来5年内知晓，但乙状结肠镜检查筛查试验在10至15年内都不会完成。由于没有关于其疗效的更好数据，大规模筛查项目将难以获得资金支持，在未来几年，结直肠癌筛查在临床环境中仍将是个人决策的问题。需要更清晰地呈现患者和医生都能理解的成本和收益情况。
