新数据支持现行指南的息肉切除后监测建议

根据美国结直肠癌多学会工作组(MSTF)更新的监测指南，基线时结肠镜检查无息肉但结直肠癌(CRC)风险为中度的成人可在10年后进行下一次结肠镜检查。该指南将于9月份的《胃肠病学》(Gastroenterology)杂志上发表。

 
David A. Lieberman博士

第一作者波兰Oregon医科大学的David A. Lieberman博士及其同事说，新的问题(如间隔CRC的风险、近端CRC风险以及锯齿状息肉在癌症发生中的作用等)促使他们对指南进行更新，指南的上一次更新时间为2006年。

工作组由来自美国胃肠病学会(ACG)、美国胃肠协会研究所(AGAI)和美国胃肠内镜学会(ASGE)的专家组成。总体而言，建议并无显著变化，但工作组回顾了最近期的文献，并发现了一些证据，支持目前对于基线筛查时为中度CRC风险的成人进行监测和筛查的时间间隔。

新证据支持的建议包括：对无息肉者的监测间隔为10年，对于有1~2个10 mm以下管状腺瘤患者的监测间隔为5~10年；对于3~10个任意大小管状腺瘤患者的监测间隔为3年；对于有1个或多个10 mm或更大管状腺瘤患者的监测间隔也为3年。并且，自2006年以来报告的数据支持对于有1个或多个绒毛状腺瘤患者的监测间隔为3年。

因无新证据而保持不变的建议为：对于直肠或乙状结肠增生性腺瘤个体的监测间隔为10年，对于有10个以上腺瘤患者的监测间隔应少于3年，对于高分级发育不良腺瘤病例的监测间隔为3年。并且，对于在基线结肠镜检查发现锯齿状病变的患者，也应纳入监测计划。对于有1个或多个不足10 mm且无发育不良的无蒂锯齿状腺瘤个体，应在5年后行再次筛查。对于有1个或多个10 mm或10 mm以上无蒂锯齿状腺瘤、任何伴有发育不良的无蒂锯齿状腺瘤或经典锯齿状腺瘤个体，应于3年后再次筛查。对于有锯齿状息肉病综合征(SPS)的个体，应于1年后进行再次筛查。SPS定义为符合以下3项标准中的1项(与世界卫生组织的定义一致)：在乙状结肠近端有至少5个锯齿状息肉，其中至少有2个不小于10 mm；有SPS家族史的患者在乙状结肠近端发现任何锯齿状息肉；在整个结肠部分有20个以上任意大小的锯齿状息肉。

作者指出，当前指南证据的质量较低，并且需要更新。“关于切除后的监测间隔，尚无纵向研究作为依据。”此外，指南中指出，鉴于新的证据提示结肠镜风险随年龄增长而增高，当风险超过获益时，应停止监测和筛查。工作组指出：“美国预防服务工作组确定，当患者年龄高于85岁时，应不再进行筛查，因为此时筛查的风险将超过潜在获益。MSTF的观点为，应基于对获益、风险和合并疾病的个体化评估，决定是否继续进行监测。”

David Lieberman博士任职于Given影像与精密仪器公司的顾问委员会。

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By: HEIDI SPLETE, Internal Medicine News Digital Network

Adults with no polyps at baseline colonoscopy and average risk for colorectal cancer can still wait 10 years until their next colonoscopy, according to updated surveillance guidelines from the U.S. Multi-Society Task Force on Colorectal Cancer. The guidelines were published in the September issue of Gastroenterology.

New concerns, including the risk of interval colorectal cancer (CRC), the risk of proximal colorectal cancer, and the role of serrated polyps in carcinogenesis prompted an update to the guidelines, which were last revised in 2006, according to lead author Dr. David A. Lieberman of Oregon Health and Science University, Portland, and his colleagues.
 
The task force is composed of GI specialists representing the three major GI professional organizations: American College of Gastroenterology (ACG), American Gastroenterological Association Institute (AGAI), and American Society for Gastrointestinal Endoscopy (ASGE).

Overall, the recommendations have not changed, but the task force reviewed the most recent literature and found additional evidence to support several categories of surveillance and screening intervals for adults with average risk of CRC at the time of a baseline screening.

Recommendations supported by new evidence include a 10-year interval for individuals with no polyps, and a 5- to 10-year interval for those with one or two tubular adenomas less than 10 mm in size. New evidence also supports a 3-year interval for patients with 3-10 tubular adenomas of any size, and also 3 years for patients with one or more tubular adenomas 10 mm or larger. In addition, data reported since 2006 support a 3-year surveillance interval for patients with one or more villous adenomas.

Recommendations that remain unchanged without additional evidence are a 10-year surveillance interval for individuals with hyperplastic polyps in the rectum or sigmoid, an interval of less than 3 years for those with more than 10 adenomas, and an interval of 3 years in cases of an adenoma with high-grade dysplasia.

In addition, serrated lesions are now included as part of the surveillance schedule after a baseline colonoscopy. Individuals with one or more sessile serrated polyps less than 10 mm in size and no dysplasia should be rescreened after 5 years. Those with one or more sessile serrated polyps 10 mm or larger, or any sessile serrated polyp with dysplasia, or a traditional serrated adenoma should be rescreened after 3 years.

Individuals with serrated polyposis syndrome (SPS) should be rescreened after 1 year. Serrated polyposis syndrome is defined as meeting one of three criteria (in agreement with the World Health Organization definition): at least five serrated polyps proximal to the sigmoid, with at least two measuring 10 mm or larger; any serrated polyps proximal to the sigmoid in patients with a family history of SPS; and more than 20 serrated polyps of any size throughout the colon.

The authors noted that the quality of the evidence supporting the current guidelines is low, and will require updates. "There are no longitudinal studies available on which to base surveillance intervals after resection," they said.

In addition, given new evidence about the increased risk of colonoscopy with advancing age, surveillance and screening should be discontinued when the risks outweigh the benefits, according to the guidelines. "The United States Preventive Services Task Forces determined that screening should not be continued after age 85 years because risk could exceed potential benefit," the task force noted. "It is the opinion of the MSTF that the decision to continue surveillance should be individualized, based on an assessment of benefit, risk, and co-morbidities."

However, "the guidelines are dynamic, and will be revised in the future, based on new evidence. This new evidence should include information about the quality of the baseline examinations," the authors said. "The task force recommends that all endoscopists monitor key quality indicators as part of a colonoscopy screening and surveillance program," they noted.

Lead author Dr. David Lieberman has served on the advisory boards of Given Imaging and Exact Sciences.