Background & Aims

Screening colonoscopies are of uncertain benefit for persons with negative results from a fecal immunochemical test (FIT). We investigated detection of CRC by colonoscopy in asymptomatic, average-risk, FIT-negative subjects.

Methods

We conducted a retrospective, population-based cohort study of 96,804 subjects with an initial negative result from a FIT at ages 50–75 years, from 2008 through 2014, who then underwent colonoscopy, using the Kaiser Permanente California databases. We identified participants diagnosed with CRC from January 1, 2008 through December 31, 2015 from a cancer registry. Subjects were followed until initial colonoscopy, health plan disenrollment, death, or December 31, 2015. We reviewed records from 400 randomly selected persons without CRC (controls) for risk features to estimate the proportion who underwent screening colonoscopy. We performed logistic regression to identify variables associated with CRC detection.

Results

Of 257 subjects with a diagnosis of CRC, 102 did not have a record of CRC risk factors; 86 of these patients (84.3%) had non-advanced-stage CRC (no regional node spread/distant metastases). Of the 400 controls, 299 (74.75%; 95% CI, 70.49%–79.01%) lacked CRC risk features, enabling estimation that 72,263 (mean age, 57.5 ± 7.0 y; 54.5% female) had undergone screening colonoscopy. CRC was detected in 1.4 per 1000 persons after 1 FIT, without association with increasing FITs (P = .97). CRC was detected in 1.3 per 1000 persons in 2 y or less after the last FIT and in 4.4 per 1000 persons more than 2 y after the last FIT (P < .001). When the last FIT was 2 y earlier or less, CRC increased from 0.7 per 1000 persons age 50–59 y to 3.1 per 1000 persons older than 70 y. Age and time from the last FIT were associated with CRC, with adjusted odds ratios of 1.08 (95% CI, 1.05–1.11) and 2.76 (95% CI, 1.28–5.95), respectively.

Conclusions

In asymptomatic, average-risk persons with a negative result from a FIT, CRC is infrequent within 2 y after the last FIT (especially for persons younger than 60 y), usually non-advanced, and unrelated to the number of FITs performed.

中文翻译：

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在粪便免疫化学测试结果为阴性的无症状、平均风险受试者中，结肠镜检查的癌症检测率较低。

背景与目标

对于粪便免疫化学测试 (FIT) 阴性结果的人，结肠镜筛查的益处不确定。我们调查了无症状、平均风险、FIT 阴性受试者通过结肠镜检查发现 CRC。

方法

我们对 96,804 名受试者进行了一项回顾性、基于人群的队列研究，这些受试者在 2008 年至 2014 年期间从 50-75 岁的 FIT 中获得初始阴性结果，然后使用 Kaiser Permanente California 数据库进行结肠镜检查。我们从癌症登记处确定了 2008 年 1 月 1 日至 2015 年 12 月 31 日期间诊断为 CRC 的参与者。受试者被随访至初始结肠镜检查、健康计划退出、死亡或 2015 年 12 月 31 日。我们审查了 400 名随机选择的无 CRC 患者（对照）的风险特征记录，以估计接受结肠镜筛查的比例。我们执行逻辑回归来识别与 CRC 检测相关的变量。

结果

在 257 名被诊断为 CRC 的受试者中，102 名没有 CRC 危险因素的记录；这些患者中有 86 名 (84.3%) 患有非晚期 CRC（无区域淋巴结扩散/远处转移）。在 400 名对照中，299 名（74.75%；95% CI，70.49%–79.01%）缺乏 CRC 风险特征，因此估计有 72,263 名（平均年龄，57.5 ± 7.0 岁；54.5% 女性）接受了结肠镜筛查。1 次 FIT 后每 1000 人中检测到 1.4 例 CRC，与增加的 FIT 无关 ( P = .97)。在最后一次 FIT 后 2 年或更短的时间内每 1000 人中检测到 1.3 例 CRC，在最后一次 FIT 后超过 2 年每 1000 人中检测到 4.4 例（P< .001）。当最后一次 FIT 提前 2 年或更短时，CRC 从 50-59 岁的每 1000 人中的 0.7 增加到每 70 岁以上的 1000 人中的 3.1。上次 FIT 的年龄和时间与 CRC 相关，调整后的优势比分别为 1.08（95% CI，1.05-1.11）和 2.76（95% CI，1.28-5.95）。

结论

在 FIT 结果为阴性的无症状、平均风险人群中，CRC 在最后一次 FIT 后 2 年内很少见（尤其是对于 60 岁以下的人），通常是非晚期的，并且与执行的 FIT 次数无关。