目标:在缺乏随机对照试验(RCT)数据的情况下,从队列研究推断结肠镜检查降低结直肠癌(CRC)死亡率的有效性。而柔性乙状结肠镜检查得到RCT数据的支持,在实践中可能更容易实施.我们对CRC的解剖分布进行了表征,以确定乙状结肠镜检查可见的比例。方法:在监测中确定了初次诊断为结直肠腺癌的患者,流行病学,和最终结果计划(2000-2020年)。从直肠到降结肠的肿瘤被归类为通过乙状结肠镜检查可见,而更多的近端肿瘤需要结肠镜检查。肿瘤位置之间的差异预后,按年龄组和阶段分层,使用2年、5年和10年的总体限制平均生存时间(RMST)进行评估。结果:在309,466例患者中,58%的肿瘤通过乙状结肠镜检查可见,包括73%的50岁以下人群(OR2.10,95%CI2.03-2.16年龄<45,OR2.20,95%CI2.13-2.27年龄45-49与年龄≥50)。男性(OR1.54,95%CI1.51-1.56)和亚洲或太平洋岛民种族(OR1.60,95%CI1.56-1.64)也与乙状结肠镜检查可见的肿瘤呈正相关。跨年龄组,对于当地疾病,对于乙状结肠镜检查中可见的肿瘤与不可见的肿瘤,RMST具有可比性。对于区域和转移性癌症,乙状结肠镜检查可见肿瘤的患者与近端肿瘤较多的患者相比,RMST有所改善.结论:58%的CRC发生在柔性乙状结肠镜检查可见的位置。软式乙状结肠镜检查应被视为CRC筛查的可行选择。特别是在不愿意或不能进行结肠镜检查的年轻患者中。
Objectives: The effectiveness of colonoscopy to reduce colorectal cancer (CRC) mortality is extrapolated from cohort studies in the absence of randomized controlled trial (RCT) data, whereas flexible sigmoidoscopy is supported by RCT data and may be easier to implement in practice. We characterized the anatomic distribution of CRC to determine the proportion that is visible with sigmoidoscopy. Methods: Patients with a primary diagnosis of colorectal adenocarcinoma were identified in the Surveillance, Epidemiology, and End Results program (2000-2020). Tumors from the rectum to the descending colon were categorized as visible by sigmoidoscopy, whereas more proximal tumors required colonoscopy. Differential prognosis between tumor locations, stratified by age groups and stage, was assessed using the overall restricted mean survival time (RMST) at 2, 5, and 10 years. Results: Among 309,466 patients, 58% had tumors visible by sigmoidoscopy, including 73% of those under age 50 (OR 2.10, 95% CI 2.03-2.16 age < 45, OR 2.20, 95% CI 2.13-2.27 age 45-49 versus age ≥ 50). Male sex (OR 1.54, 95% CI 1.51-1.56) and Asian or Pacific Islander race (OR 1.60, 95% CI 1.56-1.64) were also positively associated with tumors visualizable by sigmoidoscopy. Across age groups, for local disease, RMST was comparable for tumors visible versus not visible on sigmoidoscopy. For regional and metastatic cancer, patients with tumors visible by sigmoidoscopy had improved RMST versus those with more proximal tumors. Conclusions: 58% of CRC arises in locations visible by flexible sigmoidoscopy. Flexible sigmoidoscopy should be considered as a viable option for CRC screening, particularly in younger patients unwilling or unable to undergo colonoscopy.