Rabeneck Linda, Horton Susan, Zauber Ann G, Earle Craig
Adenocarcinoma of the colon and rectum (colorectal cancer, CRC) is the third most common cancer, the fourth most common cause of cancer death, and the second most common cancer in terms of the number of individuals living with cancer five years after diagnosis worldwide. An estimated 1,361,000 people are diagnosed with CRC annually; approximately 694,000 people die from CRC annually; and 3,544,000 individuals are living with CRC (Ferlay and others 2013). Randomized controlled trials (RCT) have shown that screening is associated with a reduction in CRC mortality; in several high-income countries (HICs), organized, population-based screening programs have been introduced, starting in 2006. Some screening tests detect cancer at an early stage when treatment is less arduous and more often results in cure. Other screening tests have the ability to detect adenomas as well as cancer. Screening provides the opportunity to identify and remove adenomas and thereby to prevent the development of the disease (Lieberman and others 2012). In general, the burden of disease, as measured by incidence and mortality rates, tracks the World Bank grouping of countries into low-, lower-middle, upper-middle, and high-income: the lowest-income countries have the lowest burden of disease. The ability to intervene to introduce screening and offer access to high-quality treatment is a function of resource availability, which is associated with income level. The ability of countries to develop interventions increases with income, suggesting a progression in policy options as country income increases. The focus of this chapter is on those who are at average risk for CRC. In our discussion of policy options, we use a slightly different typology than income for resource availability, following chapter 3 in this volume (Anderson and others 2015). The resources available at a health facility can be described as basic, limited, enhanced, and maximal. The basic level corresponds approximately to the situation in low-income countries (LICs), the limited level to the situation in rural areas of lower-middle-income countries and upper-middle-income countries, the enhanced level to the situation in urban areas of lower-middle-income and upper-middle-income countries, and the maximal level to the situation in HICs. We provide suggestions for appropriate screening and treatment strategies that correspond to these resource levels for policy makers to consider.
结肠直肠癌（结直肠癌，CRC）是全球第三大常见癌症、第四大致癌死亡原因，且就确诊后存活五年的癌症患者数量而言是第二大常见癌症。据估计，每年有136.1万人被诊断为结直肠癌；每年约有69.4万人死于结直肠癌；有354.4万人患有结直肠癌（费雷等人，2013年）。随机对照试验（RCT）表明，筛查与结直肠癌死亡率降低相关；在一些高收入国家（HICs），从2006年开始推行了有组织的、基于人群的筛查项目。一些筛查测试能在癌症早期进行检测，此时治疗难度较小且更常能治愈。其他筛查测试则有能力检测腺瘤以及癌症。筛查提供了识别并切除腺瘤的机会，从而预防疾病的发展（利伯曼等人，2012年）。一般来说，以发病率和死亡率衡量的疾病负担与世界银行将国家分为低收入、中低收入、中高收入和高收入国家的分类情况相符：收入最低的国家疾病负担最低。进行筛查并提供高质量治疗的干预能力取决于资源可用性，而资源可用性与收入水平相关。各国开展干预措施的能力随收入增加而增强，这表明随着国家收入增加，政策选择也在逐步推进。本章重点关注结直肠癌平均风险人群。在讨论政策选择时，我们采用了一种与收入不同的资源可用性分类方法，遵循本卷第3章（安德森等人，2015年）。医疗机构可用资源可描述为基本、有限、增强和最大。基本水平大致对应低收入国家（LICs）的情况，有限水平对应中低收入国家和中高收入国家农村地区的情况，增强水平对应中低收入和中高收入国家城市地区的情况，最大水平对应高收入国家的情况。我们为政策制定者提供了与这些资源水平相对应的适当筛查和治疗策略建议以供参考。
