ImportanceFor individuals without a family history of colorectal cancer (CRC), colonoscopy screening every 10 years is recommended to reduce CRC incidence and mortality. However, debate exists about whether and for how long this 10-year interval could be safely expanded.ObjectiveTo assess how many years after a first colonoscopy with findings negative for CRC a second colonoscopy can be performed.Design, Setting, and ParticipantsThis cohort study leveraged Swedish nationwide register-based data to examine CRC diagnoses and CRC-specific mortality among individuals without a family history of CRC. The exposed group included individuals who had a first colonoscopy with findings negative for CRC at age 45 to 69 years between 1990 and 2016. The control group included individuals matched by sex, birth year, and baseline age (ie, the age of their matched exposed individual when the exposed individual’s first colonoscopy with findings negative for CRC was performed). Individuals in the control group either did not have a colonoscopy during the follow-up or underwent colonoscopy that resulted in a CRC diagnosis. Up to 18 controls were matched with each exposed individual. Individuals were followed up from 1990 to 2018, and data were analyzed from November 2022 to November 2023.ExposureA first colonoscopy with findings negative for CRC, defined as a first colonoscopy without a diagnosis of colorectal polyp, adenoma, carcinoma in situ, or CRC before or within 6 months after screening.Main Outcomes and MeasuresThe primary outcomes were CRC diagnosis and CRC-specific death. The 10-year standardized incidence ratio and standardized mortality ratio were calculated to compare risks of CRC and CRC-specific death in the exposed and control groups based on different follow-up screening intervals.ResultsThe sample included 110 074 individuals (65 147 females [59.2%]) in the exposed group and 1 981 332 (1 172 646 females [59.2%]) in the control group. The median (IQR) age for individuals in both groups was 59 (52-64) years. During up to 29 years of follow-up of individuals with a first colonoscopy with findings negative for CRC, 484 incident CRCs and 112 CRC-specific deaths occurred. After a first colonoscopy with findings negative for CRC, the risks of CRC and CRC-specific death in the exposed group were significantly lower than those in their matched controls for 15 years. At 15 years after a first colonoscopy with findings negative for CRC, the 10-year standardized incidence ratio was 0.72 (95% CI, 0.54-0.94) and the 10-year standardized mortality ratio was 0.55 (95% CI, 0.29-0.94). In other words, the 10-year cumulative risk of CRC in year 15 in the exposed group was 72% that of the 10-year cumulative risk of CRC in the control group. Extending the colonoscopy screening interval from 10 to 15 years in individuals with a first colonoscopy with findings negative for CRC could miss the early detection of only 2 CRC cases and the prevention of 1 CRC-specific death per 1000 individuals, while potentially avoiding 1000 colonoscopies.Conclusions and RelevanceThis cohort study found that for the population without a family history of CRC, the 10-year interval between colonoscopy screenings for individuals with a first colonoscopy with findings negative for CRC could potentially be extended to 15 years. A longer interval between colonoscopy screenings could be beneficial in avoiding unnecessary invasive examinations.

中文翻译：

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首次结肠镜检查结果呈阴性结直肠癌与再次结肠镜检查之间的间隔较长

重要性对于没有结直肠癌 (CRC) 家族史的个人，建议每 10 年进行一次结肠镜检查，以降低结直肠癌的发病率和死亡率。然而，对于是否可以安全地延长这一 10 年间隔以及延长多长时间，仍存在争议。目的评估第一次结肠镜检查结果呈阴性，CRC 阴性后多少年可以进行第二次结肠镜检查。设计、设置和参与者本队列研究利用了瑞典全国登记数据用于检查无 CRC 家族史的个体的 CRC 诊断和 CRC 特异性死亡率。暴露组包括 1990 年至 2016 年间 45 岁至 69 岁期间首次接受结肠镜检查且结直肠癌结果呈阴性的个体。对照组包括按性别、出生年份和基线年龄（即与其匹配的暴露者的年龄）相匹配的个体。当暴露个体进行第一次结肠镜检查且结果呈结直肠癌阴性时）。对照组的个体要么在随访期间没有进行结肠镜检查，要么接受结肠镜检查后诊断为结直肠癌。每个暴露个体与多达 18 个对照相匹配。从 1990 年至 2018 年对个体进行随访，并从 2022 年 11 月至 2023 年 11 月对数据进行分析。 首次结肠镜检查结果显示 CRC 阴性，定义为首次结肠镜检查之前未诊断出结直肠息肉、腺瘤、原位癌或 CRC或筛查后6个月内。 主要结果和措施主要结果是CRC诊断和CRC特异性死亡。计算10年标准化发病率和标准化死亡率，以根据不同的随访筛查间隔比较暴露组和对照组的CRC和CRC特异性死亡风险。结果样本包括110 074人（65 147名女性[59.2 %]）在暴露组中，1 981 332（1 172 646 名女性 [59.2%]）在对照组中。两组中个体的中位年龄 (IQR) 均为 59 (52-64) 岁。在对首次结肠镜检查结果为 CRC 阴性的个体进行长达 29 年的随访期间，发生了 484 例 CRC 事件和 112 例 CRC 特异性死亡。第一次结肠镜检查结果显示结直肠癌呈阴性后，暴露组的结直肠癌和结直肠癌特异性死亡风险在 15 年内显着低于匹配对照组。首次结肠镜检查结果呈阴性 CRC 后 15 年，10 年标准化发病率为 0.72（95% CI，0.54-0.94），10 年标准化死亡率为 0.55（95% CI，0.29-0.94） 。换句话说，暴露组第15年的10年累积CRC风险是对照组10年累积CRC风险的72%。对于首次结肠镜检查且结直肠癌阴性的个体，将结肠镜检查筛查间隔从 10 年延长至 15 年，可能会错过仅 2 例结直肠癌病例的早期发现，并防止每 1000 人中 1 例结直肠癌特异性死亡，同时可能避免 1000 次结肠镜检查。结论和相关性这项队列研究发现，对于没有 CRC 家族史的人群，首次结肠镜检查结果为 CRC 阴性的个体的结肠镜检查之间的 10 年间隔可能会延长至 15 年。结肠镜检查之间较长的间隔可能有利于避免不必要的侵入性检查。