Post-polypectomy Surveillance for Reducing Colon Cancer Incidence and Mortality

项目总结 结直肠癌(CRC)是美国癌症死亡的第二大原因。研究表明， 一贯表明，筛查可以降低结直肠癌的发病率和死亡率。筛查的有效性 通常被归因于检测和切除癌前息肉和可治愈的癌症。和往常一样 在实践中，许多息肉患者的常规随访包括重复监测 结肠镜检查以发现和切除更多的息肉和癌症。然而，增加的好处 监测结肠镜检查与基线结肠镜检查息肉摘除相比尚不清楚。事实上，之前的研究已经 没有注重监测的有效性，也没有具体确定是否有一项临床战略 基线息肉切除术后的系统监测可降低发生或死于结直肠的风险 癌症，与没有监控相比。尽管在知识上存在这样的差距，但目前的指南建议 监视结肠镜检查对大多数息肉患者的影响。由于结肠镜检查是患者的负担， 与出血和代价高昂的风险相关，确定监测是否会减少 CRC风险。我们的具体目标是确定息肉切除术后监测结肠镜检查是否减少 结直肠癌发病率(目标1)和死亡率(目标2)。为了实现这些目标，我们将利用以前建立的 退伍军人事务部内接受结肠镜检查并切除息肉的40多万人的队列 事务(VA)。使用病例队列设计，所有由退伍军人事务部中央癌症识别的事件CRC患者 登记，所有由国家死亡指数确定的致命结直肠癌患者，以及随机抽样的 那些在基线时切除了息肉的人将被选为研究对象。我们将使用病历 审查以确定暴露于监视结肠镜检查并测量可能影响结直肠癌的其他因素 风险。观察到的监测结肠镜检查的发生和时间将用一个时间总结- 息肉切除术后监测指南的依从性暴露变量。CRC 将比较暴露于与未暴露于空气中的个体的发病率以及结直肠癌死亡率。 监视结肠镜检查，考虑可能影响结直肠癌风险的其他因素。

PROJECT SUMMARY Colorectal cancer (CRC) is the 2nd leading cause of cancer death in the United States. Research has consistently shown that screening reduces risks for CRC incidence and mortality. Effectiveness of screening has generally been attributed to detection and removal of precancerous polyps and curable cancers. In usual practice, routine follow up for many patients with polyps removed at baseline includes repeat surveillance colonoscopy to detect and resect additional polyps and cancer. However, the incremental benefit of surveillance colonoscopy over baseline colonoscopy with polyp removal is unclear. Indeed, prior research has not focused on effectiveness of surveillance and has not specifically determined whether a clinical strategy of systematic surveillance after baseline polypectomy reduces the risk of developing or dying from colorectal cancer, compared to no surveillance. Despite this gap in knowledge, current guidelines recommend routine surveillance colonoscopy for the majority of patients with polyps. Since colonoscopy is a burden on patients, associated with risks such as bleeding, and costly, it is imperative to establish whether surveillance reduces CRC risk. Our Specific Aims are to determine whether post polypectomy surveillance colonoscopy reduces CRC incidence (Aim 1) and mortality (Aim 2). To accomplish these aims, we will utilize a previously established cohort of over 400,000 individuals who had colonoscopy with polyp removal within the Department of Veterans Affairs (VA). Using a case-cohort design, all individuals with incident CRC identified by the VA Central Cancer Registry, all individuals with fatal CRC identified by the National Death Index, as well as a random sample of those who had polyps removed at baseline will be selected for study inclusion. We will use medical record review to determine exposure to surveillance colonoscopy and measure other factors that may influence CRC risk. Observed occurrence and timing of surveillance colonoscopy delivered will be summarized using a time- dependent exposure variable that characterizes adherence to post-polypectomy surveillance guidelines. CRC incidence, as well as CRC mortality will be compared among individuals exposed versus unexposed to surveillance colonoscopy, taking into account other factors that may influence CRC risk.