Colonoscopy in young onset colorectal cancer

项目总结 在中国，结直肠癌(CRC)占癌症发病率的8%，占癌症相关死亡的8% 美国。虽然近年来结直肠癌风险和结直肠癌相关死亡率总体上有所下降，但 在50岁以上的成年人中，结直肠癌病例的比例--即年轻发病的结直肠癌-- 增加了。建议早期发现YCRC的一种临床策略是成人结肠镜检查 有可能增加YCRC风险的情况，如缺铁性贫血(IDA)或便血(可见 粪便中有血)。在这些病例中，结肠镜检查排除了CRC，并已被证明是特别 对老年人有效。然而，几乎没有证据表明成年人之间的相对益处。 &lt；50。鉴于YCRC发病率的增加，美国癌症协会推荐的第二种临床策略 社会涉及将结直肠癌筛查开始年龄从50岁降低到45岁，尽管缺乏证据表明 早期筛查可改善50岁成人的结直肠癌相关预后。虽然之前的指导方针 建议仅在50岁之前对有结直肠癌家族史的成年人进行结直肠癌筛查，这代表 仅占所有CRC病例的30%，这意味着确定最有可能从YCRC受益的50岁成年人- 相关的结肠镜检查仍不清楚。此外，还没有即将到来的RCT提供像这样的干预 结肠镜检查结直肠癌相关疾病或筛查无症状成年人，突出紧急 需要了解YCRC相关结肠镜检查有益于50岁的成年人。我们的研究将使用国家 退伍军人事务部(VA)企业数据仓库中的电子健康记录和基于索赔的数据 (CDW)通过评估这两种结肠镜摄取的临床策略来解决文献中的关键空白 以解决YCRC的发病率和死亡率。首先，我们将研究结肠镜检查的好处 50岁的退伍军人患有可能增加CRC风险的条件(缺铁性贫血或便血)，通过比较CRC风险 在暴露于IDA或便血(目标1a)的成年人中，检查及时结肠镜检查的比例 ≤60天缺铁性贫血或便血鉴定(目标1b)，并比较年轻结直肠癌发病率、检测阶段 以及患有缺铁性贫血或便血的退伍军人的结肠镜检查死亡率(目标1c)。接下来，我们将 比较所有18-49岁退伍军人接受结肠镜检查对YCRC益处的影响(目标2)。 我们的研究将是迄今为止美国对早期接受结肠镜检查的最全面的检查 将对当前的临床指南和当前的结直肠癌筛查政策产生重要影响。 主要优势包括：(1)使用来自最大的集成医疗保健系统的电子病历和基于索赔的数据 在美国；(2)VA研究在美国临床实践的变化中发挥了关键作用；以及(3)最大的 到目前为止，50岁成年人对结肠镜检查的评估。最后，本研究提供了一个高质量的 博士后培训机会，了解目前使用结肠镜检查结直肠癌的方法，并 培养癌症流行病学和生物统计学的关键技能，成为一名合格的独立调查员。

PROJECT SUMMARY Colorectal cancer (CRC) accounts for 8% of cancer incidence and 8% of cancer-related mortality in the United States. While CRC risk and CRC-related mortality overall have decreased in recent years, the proportion of CRC cases among adults ages <50—known as young onset colorectal cancer (YCRC)—has increased. One clinical strategy recommended to detect YCRC earlier is colonoscopy for adults presenting with conditions that might increase YCRC risk, such as iron deficiency anemia (IDA) or hematochezia (visible blood in stool). Colonoscopy in these cases is conducted rule out CRC and has been proven to be particularly effective among elderly adults. However, little evidence exists about the relative benefit among adults ages <50. In light of increased YCRC incidence, a second clinical strategy recommended by the American Cancer Society involves lowering the age of CRC screening initiation from 50 to 45, despite a paucity of evidence that early screening initiation improves CRC-related outcomes in adults ages <50. While previous guidelines advised CRC screening prior to age 50 only among adults with reported family history of CRC, this represents only 30% of all CRC cases, meaning that identification of adults ages <50 most likely to benefit from YCRC- related colonoscopy remains unclear. Furthermore, there are no imminent RCTs offering interventions like colonoscopy for work-up of CRC-related conditions or screening asymptomatic adults, highlighting an urgent need to learn about YCRC-related colonoscopy benefit among adults ages <50. Our study will use national electronic health records and claims-based data from the Veterans Affairs (VA) Corporate Data Warehouse (CDW) to address key gaps in the literature by evaluating these two clinical strategies for colonoscopy uptake to address YCRC incidence and mortality. First, we will examine the benefits of colonoscopy uptake among Veterans ages <50 with conditions (IDA or hematochezia) that may increase CRC risk by comparing CRC risk among adults exposed to IDA or hematochezia (Aim 1a), examining proportion of timely colonoscopy uptake ≤60 days of IDA or hematochezia identification (Aim 1b), and comparing YCRC incidence, stage at detection and mortality by colonoscopy uptake among Veterans with IDA or hematochezia (Aim 1c). Next, we will compare the impact of exposure to colonoscopy on YCRC benefits among all Veterans ages 18-49 (Aim 2). Our study will be the most comprehensive examination of early exposure to colonoscopy in the US to date and will have important implications on current clinical guidelines and contextualize current CRC screening policy. Major strengths include: (1) use of EHR and claims-based data from the largest integrated healthcare system in the US; (2) VA studies have played critical roles in US clinical practice changes; and (3) the largest assessment of colonoscopy uptake among adults ages <50 to date. Finally, this study offers a high-quality postdoctoral training opportunity to understand current methods of CRC detection using colonoscopy, and to develop key skills in cancer epidemiology and biostatistics to become a qualified independent investigator.