Interval for colon cancer screening by sigmoidoscopy

描述（由申请人提供）： 通过乙状结肠镜检查筛查结直肠癌（CRC）， 识别和切除癌前病变（腺瘤性息肉），因此 预防癌症的发生。目前的指南建议筛查 对于50岁及以上的平均风险成年人，每3至5年一次。几乎没有 然而，有证据支持这样的间隔，事实上， 有证据表明，这种间隔是不必要的频繁。 拟议研究的目的是确定适当的 通过乙状结肠镜检查筛查CRC的间隔。所述结肠直肠癌 北方加州Kaiser Permanente的CoCaP项目 （KPNC）已定期输入其乙状结肠镜检查筛查项目的结果 输入电脑数据库利用这一独特资源的数据， 大约100，000名50岁及以上的人处于低风险， CRC，并且在基线时腺瘤性息肉筛查阴性 1994年至1996年期间，将进行审查。信息 筛查程序、病史和人口统计学变量可用 的电子档案，而CRC的事故个案将使用 人口登记处。该人群中CRC的发病率将为 计算筛选后连续1年的间隔;所有发生率 将通过直接标准化根据年龄进行调整。CRC的相对风险 筛选后的后期（与第一年相比 筛选后）将用于确定筛选间隔， 与最大的风险降低相关，同时最大限度地提高 连续筛选检查之间的时间。 将使用类似的方法来建议第二次筛查间隔 CoCaP项目中约15，000名患有腺瘤性乳腺癌的个体的队列 在基线时诊断和治疗的息肉。这将提供有用的信息 关于筛查阳性个体的筛查间隔。 这项研究将为解决以下问题提供一个合理的基础： 乙状结肠镜检查CRC的适当筛查间隔。这些信息将 允许降低CRC发病率和死亡率，同时最大限度地减少 与乙状结肠镜检查筛查项目相关的费用。

DESCRIPTION (provided by applicant): Screening for colorectal cancer (CRC) by sigmoidoscopy results in the identification and removal of pre-cancerous lesions (adenomatous polyps), thus preventing incident cases of cancer. Current guidelines recommend screening for average-risk adults aged 50 and above every 3 to 5 years. There is little evidence supporting such an interval, however, and in fact there is some evidence suggesting that this interval is unnecessarily frequent. The objective of the proposed research is to determine an appropriate interval for screening for CRC by sigmoidoscopy. The Colorectal Cancer Prevention (CoCaP) program of Kaiser Permanente of Northern California (KPNC) has routinely entered results of their sigmoidoscopy screening program into a computer database. Using data from this unique resource, a cohort of approximately 100,000 individuals aged 50 and older who are at low risk for CRC, and who screened negative for adenomatous polyps at a baseline examination between 1994 and 1996, will be identified. Information regarding screening procedures, medical history, and demographic variables is available in electronic files, and incident cases of CRC will be identified using a population registry. Incidence rates of CRC in this population will then be calculated for successive one-year intervals following screening; all rates will be adjusted for age by direct standardization. Relative risks of CRC for later time periods following screening (as compared to the first year post-screen) will then be used to determine the screening interval that is associated with the greatest risk reduction, while maximizing the amount of time between successive screening examinations. Similar methods will be used to suggest a screening interval for a second cohort of about 15,000 individuals in the CoCaP program who had adenomatous polyps diagnosed and treated at baseline. This will provide useful information regarding screening interval in screen-positive individuals. This study will provide a rational basis to address the question of appropriate screening interval for CRC by sigmoidoscopy. Such information will allow for the reduction in CRC incidence and mortality, while minimizing the costs associated with a sigmoidoscopy screening program.