Abnormal Fecal Test Results Associated with Colorectal Cancer Incidence and Mortality

项目概要/摘要 结直肠癌（CRC）是美国癌症相关死亡的第二大常见原因 （US）.美国预防服务工作队已经制定了几种筛查模式，以早期发现 CRC，如粪便免疫化学试验（FIT）和粪便潜血试验（FOBT）。FIT和FOBT是 在美国使用的常用筛选工具。FIT/FOBT异常时，必须进行诊断性结肠镜检查 以评估癌前病变和癌性结直肠病变。文献稀少，结果各异 关于如何快速完成随访时间的建议。研究表明， 诊断随访的建议在FIT/FOBT异常后6个月至24个月不等。 此外，研究主要来自台湾和以色列的国际人群。目前，只有 一项美国研究检查了诊断性结肠镜检查时间和结直肠结局的影响。这项研究只 关注CRC发病率和诊断阶段，而不是CRC死亡率。此外，研究人群为 仅限于加州。总的来说，未能完成诊断性结肠镜检查与 FIT/FOBT异常后对CRC预后的影响尚未得到广泛研究。我们的研究将使用国家 退伍军人事务部（VA）的电子健康记录和基于索赔的数据， 通过评价诊断性结肠镜检查和多个CRC终点之间的关系，来填补文献中的空白。 首先，我们将研究暴露与未暴露个体之间发生和致命CRC癌症的风险 FIT/FOBT异常后的诊断性结肠镜检查（目的1）。接下来，我们将确定时间的影响， 结肠镜检查，在暴露于诊断性结肠镜检查的个体中，对CRC发病率，诊断时的分期， 致命的癌症（目标2）。最后，我们将描述社会人口统计学和临床 FIT/FOBT异常后影响诊断完成的变量（如Charlson合并症、年龄、人种） 筛选试验（目标3）。

PROJECT SUMMARY/ABSTRACT Colorectal cancer (CRC) is the second most common cause of cancer-related mortality in the United States (US). The US Preventive Services Task Force has instituted several modes of screening for early detection of CRC, such as the fecal immunochemical test (FIT) and fecal occult blood tests (FOBT). FIT and FOBT are common screening tool used in the US. FIT/FOBT must be followed by diagnostic colonoscopy when abnormal to evaluate for precancerous and cancerous colorectal lesions. The literature is scarce and has varied results on recommendations for how quickly to complete follow-up time. Studies suggesting an optimal window for diagnostic follow-up vary their recommendations from 6 months to 24 months after abnormal FIT/FOBT. Additionally, studies mainly came from international populations in Taiwan and Israel. Currently, there was only one US study examining the effect of time to diagnostic colonoscopy and colorectal outcomes. This study only looked at CRC incidence and stage of diagnosis, and not CRC mortality. Additionally, the study population was limited to the state of California. Overall, the relationship between failure to complete diagnostic colonoscopy after an abnormal FIT/FOBT on CRC outcomes has not been widely studied. Our study will use national electronic health records and claims-based data from the Department of Veterans Affairs (VA) to address key gaps in the literature by evaluating the relationship between diagnostic coloscopy and multiple CRC endpoints. First, we will examine the risk for incident and fatal CRC cancer among individuals exposed versus unexposed to diagnostic colonoscopy after abnormal FIT/FOBT (Aim 1). Next, we will determine the effect of time to colonoscopy, among individuals exposed to diagnostic colonoscopy, on CRC incidence, stage at diagnosis, and fatal cancer (Aim 2). Lastly, we will characterize the extent to which sociodemographic and clinical variables (e.g. Charlson comorbidity, age, race) impact diagnostic completion after an abnormal FIT/FOBT screening test (Aim 3).