慢性便秘可能增加结直肠癌风险

根据对一个美国大型回顾性索赔数据库资料的分析，慢性便秘可能使患者更易发生结直肠癌和良性肿瘤。

澳大利亚新南威尔士州纽卡斯尔大学的Nicholas Talley博士报告，该研究纳入1999年1月~2011年9月期间至少2次被诊断为慢性便秘(间隔60~365天)的年龄≥18岁的成年患者。排除肠易激综合征或腹泻患者，以及在首次诊断为便秘后至少12个月未继续参与健康计划的患者。对照受试者为观察期内从未被诊断为便秘且从未接受处方泻药治疗者，基于出生年份、性别和居住地区与病例进行匹配，病例与对照人数比例为1:3。慢性便秘患者和对照者的平均年龄为61.9岁，其中1/3为男性。平均观察期接近4年。

结果显示，在这项研究中，慢性便秘患者的结直肠癌患病率为2.7%，对照者为1.7%；慢性便秘患者的良性肿瘤患病率为24.8%，对照者为11.9%。28,854例慢性便秘成年患者发生结直肠癌的风险为86,562例无慢性便秘对照者的1.78倍，并且慢性便秘患者发生良性肿瘤的风险为对照者的2.7倍。经校正潜在混淆因素，包括年龄、性别、恶性疾病家族史和其他非胃肠道疾病后，慢性便秘患者的结直肠癌和良性肿瘤风险仍保持增高。尽管上述结果未能证实慢性便秘与结直肠癌或良性肿瘤之间存在因果关系，但提示具有很强的相关性。

研究者总结认为，临床医生应注意慢性便秘与结直肠癌、良性肿瘤之间的潜在关系，并对患者进行相应的监测和治疗。

该研究由武田制药公司资助，Talley博士接受了该公司提供的研究支持。合著者为武田或Analysis Group公司雇员，Analysis Group公司接受了武田公司提供的咨询费。

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By: SHARON WORCESTER, Internal Medicine News Digital Network

Chronic constipation may predispose affected patients to developing colorectal cancer and benign neoplasms, according to an analysis of data from a large retrospective U.S. claims database.

The risk of developing colorectal cancer was 1.78 times higher among 28,854 adults with chronic constipation than among 86,562 controls without chronic constipation, and the risk of developing benign neoplasms was 2.7 times higher in those with chronic constipation, Dr. Nicholas Talley reported in a poster at the annual meeting of the American College of Gastroenterology.

The risk of colorectal cancer and benign neoplasms among those with chronic constipation remained "consistently high" after researchers controlled for potential confounding factors, including age, gender, family history of malignancies, and other nongastrointestinal morbidities, said Dr. Talley of the University of Newcastle, Callaghan, New South Wales, Australia.

Patients included adults aged older than 18 years who received at least two diagnoses of chronic constipation 60-365 days apart between January 1999 and September 2011. Those with irritable bowel syndrome or diarrhea were excluded, as were those who did not remain enrolled in their health plans for at least 12 months from the date of their first eligible diagnosis of constipation.

The investigators matched control subjects, who had never been diagnosed with constipation and never had a prescription filled for a laxative during the observation period, with case patients in a 1:3 ratio based on year of birth, sex, and region of residence.

Patients and controls had a mean age of 61.9 years, and one-third were men. The mean observation period was nearly 4 years.

The prevalence of colorectal cancer in this study was 2.7% in the patients and 1.7% in the controls; the prevalence of benign neoplasms was 24.8% in the patients and 11.9% in the controls, Dr. Talley said.

Although the findings do not prove a causal link between chronic constipation and colorectal cancer or benign neoplasms, they do suggest a strong association, he said in a press statement.

"The postulated causal link is that longer transit times increase the duration of contact between the colonic mucosa and concentrated carcinogens such as bile acids in the lumen," he said.

This association deserves further investigation to more thoroughly explore and to better understand possible causal elements, he added.

This is particularly important because prospective cohort studies have failed to identify a similar association to that seen in this retrospective review, suggesting that those findings are affected by recall bias, he said.

While further study is needed, practitioners should be aware of the potential relationship between chronic constipation and development of colorectal cancer and benign neoplasms, and should monitor and treat patients accordingly, he concluded.

Dr. Talley received research support from Takeda Pharmaceuticals International, which supported the study. Coauthors were employed by Takeda or by Analysis Group Inc., which has received consulting fees from Takeda.