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.
目的：在缺乏随机对照试验数据的情况下，结肠镜检查降低结直肠癌死亡率的效果主要基于队列研究的外推，而软式乙状结肠镜检查已有随机对照试验数据支持，且临床实践中可能更易实施。本研究通过分析结直肠癌的解剖分布特征，以明确乙状结肠镜可检出的肿瘤比例。 方法：通过美国国家癌症研究所监测、流行病学和最终结果数据库（2000–2020年）筛选原发性结直肠腺癌患者。将直肠至降结肠的肿瘤归类为乙状结肠镜可检范围，更近端肿瘤则需结肠镜检查。按年龄组和分期分层，采用2年、5年和10年限制性平均生存时间评估不同肿瘤部位的预后差异。 结果：在309,466例患者中，58%的肿瘤位于乙状结肠镜可检范围，其中50岁以下患者比例达73%（年龄<45岁：OR 2.10，95% CI 2.03–2.16；45–49岁：OR 2.20，95% CI 2.13–2.27；均以≥50岁为参照）。男性（OR 1.54，95% CI 1.51–1.56）及亚裔或太平洋岛民种族（OR 1.60，95% CI 1.56–1.64）也与乙状结肠镜可检肿瘤呈正相关。各年龄组中，局部病变患者无论肿瘤是否位于乙状结肠镜可检范围，其限制性平均生存时间均无显著差异；而对于区域性和转移性癌症，乙状结肠镜可检肿瘤患者的限制性平均生存时间优于近端肿瘤患者。 结论：58%的结直肠癌发生于软式乙状结肠镜可检部位。对于不愿或无法接受结肠镜检查的人群，特别是年轻患者，应考虑将软式乙状结肠镜作为结直肠癌筛查的可行方案。
肿瘤(癌症)患者之家