Effectiveness of Screening Colonoscopy in Reducing Deaths from Colorectal Cancer

描述(申请人提供)：结肠癌和直肠癌(CRC)是美国第二大癌症死亡原因，可以在早期、更可治愈的阶段被发现，甚至可以使用现有的筛查技术进行预防。尽管美国的一些专家小组认为结肠镜检查是标准，但目前只有有限的直接证据支持结肠镜检查在中等风险成年人中越来越多地使用。结肠镜检查比其他筛查检查有更高的风险和成本。最近的研究报告称，结肠镜检查并不能降低右半结肠癌的死亡率，右半结肠癌是乙状结肠镜检查无法触及的部分。然而，这些发现是有争议的，因为该研究无法区分筛查和诊断用途，也无法准确评估结肠镜检查的完整性。该项目的目标是通过提供证据来显示结肠镜检查声称的好处是否在实践中实现，从而为临床和政策决策提供信息。主要的具体目的是评估筛查结肠镜检查在降低平均风险成人结直肠癌死亡率方面的有效性，与没有筛查的相比，分别对右侧和左侧的癌症进行筛查。我们的次要目标是：1)确定结肠镜检查的完整性对其有效性的影响；2)比较筛查结肠镜检查与乙状结肠镜检查的有效性。我们将使用病例对照设计，嵌套在参与研究联盟癌症研究网络(CRN)的3个地点接受护理的历史队列中。这些网站为其成员提供从筛查到临终关怀的完整的癌症护理，并提供有关CRC筛查的信息，这些信息可与大量种族和社会经济不同的人的诊断和特定原因死亡数据联系起来。我们将在诊断日期为52岁或以上的参保者中确定2007至2014年间至少1,200例CRC死亡病例，每个病例在每个健康计划中都与根据年龄、性别和参保史随机选择的两个对照组相匹配。我们将确定癌症诊断前至少10年的筛查历史，将筛查与诊断程序区分开来，使用标准化的有针对性的图表审查和其他来源。样本量将为单独评估位于右半结肠的肿瘤提供足够的能量。该项目将由一个代表流行病学、病例控制方法学、生物统计学、胃肠病学和初级保健的经验丰富的跨学科小组执行。团队成员是国家在儿童疾病筛查研究和政策方面的领导者。该项目与现有的NCI和CRN目标协同：1)开发提供临床、政策相关信息的方法和途径；2)告知临床和公共卫生关于结直肠癌筛查的决定。这项应用也响应了NCI的优先事项，即提高对用于筛查CRC的测试的有效性和相对有效性的了解，CRC是一种“健康差距状况”，并解决了健康人2010年减少癌症死亡的目标。

DESCRIPTION (provided by applicant): Cancers of the colon and rectum (CRC), the second leading cause of cancer death in the US, can be detected at an early, more curable, stage or even prevented using available screening techniques. Although some expert groups in the US consider colonoscopy to be the standard, there is currently only limited direct evidence to support its increasing use for screening in average risk adults. Colonoscopy has higher risks and costs than other screening tests. Recent studies reported that colonoscopy did not reduce mortality from right-sided colon cancers, the part of the colon that is beyond the reach of sigmoidoscopy. However, those findings were controversial because that study was unable to distinguish screening from diagnostic uses or accurately assess the completeness of colonoscopies. This project's goal is to inform clinical and policy decisions by providing evidence to show whether the purported benefits of colonoscopy are realized in practice. The primary specific aim is to estimate the effectiveness of screening colonoscopy in reducing death from CRC among average-risk adults when compared to no screening, overall and separately for right- and left-sided cancers. Our secondary aims are to: 1) determine the impact of the completeness of colonoscopy examinations on its effectiveness; and 2) compare the effectiveness of screening colonoscopy relative to sigmoidoscopy. We will use a case-control design nested in an historical cohort of persons receiving care at 3 sites participating in a research consortium, Cancer Research Network (CRN). These sites provide the full continuum of cancer care to their members ranging from screening through end of life care, and provide access to information on CRC screening that can be linked to diagnosis and cause-specific mortality data on large numbers of racially and socioeconomically diverse persons. We will identify at least 1,200 cases of CRC deaths between 2007 and 2014 among enrollees who were 52 years or older at the date of the diagnosis, each matched within each health plan to two randomly selected controls based on age, sex and enrollment history. We will identify screening history for a minimum of 10 years prior to cancer diagnosis, differentiating screening from diagnostic procedures, using standardized targeted chart reviews and other sources. The sample size will provide sufficient power for separate evaluations of tumors located in the right colon. This project will be carried out by an experienced interdisciplinary team representing epidemiology, case-control methodology, biostatistics, gastroenterology and primary care. Team members are national leaders in CRC screening research and policy. This project is in synergy with existing NCI and the CRN goals to: 1) develop methods and approaches to provide clinical, policy-relevant information; and 2) inform clinical and public health decisions on CRC screening. This application is also responsive to the NCI's priority to improve understanding of the effectiveness and comparative effectiveness of tests used in screening for CRC, a "health disparity condition", and addresses Healthy People 2010 goals to reduce cancer death.