Singh Harminder, Turner Donna, Xue Lin, Targownik Laura E, Bernstein Charles N
Department of Internal Medicine, Cancer Care Manitoba, University of Manitoba, Winnipeg.
JAMA. 2006 May 24;295(20):2366-73. doi: 10.1001/jama.295.20.2366.
Limited evidence exists to guide the optimal frequency of repeat endoscopic examination for colorectal cancer screening after a negative colonoscopy.
To determine the duration and magnitude of the risk of developing colorectal cancer following performance of a negative colonoscopy.
DESIGN, SETTING, AND PATIENTS: Population-based retrospective analysis of individuals whose colonoscopy evaluations did not result in a diagnosis of colorectal neoplasia. Patients who had been evaluated between April 1, 1989, and December 31, 2003, were identified using Manitoba Health's physician billing claims database (N = 35 975). Standardized incidence ratios (SIRs) were calculated to compare colorectal cancer incidence in our cohort with colorectal cancer incidence in the provincial population. Stratified analysis was performed to determine the duration of the reduced risk. Patients with a history of colorectal cancer prior to the index colonoscopy, inflammatory bowel disease, resective colorectal surgery, and lower gastrointestinal endoscopy within the 5 years before the index colonoscopy were excluded. Cohort members were followed up from the time of the index colonoscopy until diagnosis of colorectal cancer, death, out-migration from Manitoba, or end of the study period on December 31, 2003.
Incidence of colorectal cancer.
A negative colonoscopy was associated with SIRs of 0.69 (95% confidence interval [CI], 0.59-0.81) at 6 months, 0.66 (95% CI, 0.56-0.78) at 1 year, 0.59 (95% CI, 0.48-0.72) at 2 years, 0.55 (95% CI, 0.41-0.73) at 5 years, and 0.28 (95% CI, 0.09-0.65) at 10 years. The proportion of colorectal cancer located in the right side of the colon was significantly higher in the colonoscopy cohort than the rate in the Manitoba population (47% vs 28%; P<.001).
The risk of developing colorectal cancer remains decreased for more than 10 years following the performance of a negative colonoscopy. There is a need to improve the early detection rate of right-sided colorectal neoplasia in usual clinical practice.
关于结肠镜检查结果为阴性后进行重复结肠镜检查的最佳频率，目前可用于指导的证据有限。
确定结肠镜检查结果为阴性后发生结直肠癌的风险持续时间和风险程度。
设计、地点和患者：基于人群的回顾性分析，纳入结肠镜检查未诊断为结直肠肿瘤的个体。利用曼尼托巴省卫生部门的医生计费索赔数据库，确定了1989年4月1日至2003年12月31日期间接受评估的患者（N = 35975）。计算标准化发病率比（SIR），以比较我们队列中的结直肠癌发病率与该省人群的结直肠癌发病率。进行分层分析以确定风险降低的持续时间。排除在首次结肠镜检查前有结直肠癌病史、炎症性肠病、结直肠切除手术以及在首次结肠镜检查前5年内进行过下消化道内镜检查的患者。对队列成员从首次结肠镜检查时开始随访，直至诊断为结直肠癌、死亡、从曼尼托巴省迁出或2003年12月31日研究期结束。
结直肠癌发病率。
阴性结肠镜检查后6个月的SIR为0.69（95%置信区间[CI]，0.59 - 0.81），1年时为0.66（95%CI，0.56 - 0.78），2年时为0.59（95%CI，0.48 - 0.72），5年时为0.55（95%CI，0.41 - 0.73），10年时为0.28（95%CI，0.09 - 0.65）。结肠镜检查队列中位于结肠右侧的结直肠癌比例显著高于曼尼托巴省人群中的比例（47%对28%；P <.001）。
阴性结肠镜检查后10多年内发生结直肠癌的风险仍然降低。在常规临床实践中，需要提高右侧结直肠肿瘤的早期检出率。
