结肠直肠癌 指的是结肠癌和直肠癌, and is currently the second leading cause of cancer death in the United States. 然而，如果发现得早，许多结肠和 直肠癌 可以成功治疗. The best way to decrease your risk of serious cancer is to get tested for it.

Because colon and rectum are both parts of the large intestine, 这些地区的癌症筛查是相似的. These tests can also help your doctor identify non-cancer causes of problems you might be experiencing, 比如慢性腹泻, 便秘, stomach pain and signs of intestinal bleeding (blood in the stool or low iron).

Who Should Get Screened and When: 结肠癌 Screening Guidelines

The timeline for colorectal cancer screening differs and depends on which risk category you are in. 结直肠癌的危险因素 包括年龄, 种族, 生活方式, 家族史和基因, 以及某些健康状况的个人病史. Discuss with your primary care provider how to assess your risk, and plan screenings accordingly.

对于处于平均风险的人来说 美国癌症协会 recommends starting colorectal cancer screenings (typically colonoscopies) at age 45 and continuing them until age 75, 当评估筛查的必要性时. 结肠直肠癌 screening is no longer needed for people 85 and older.

第一次结肠镜检查之后, the endoscopist will determine when your next 结肠镜检查 should be, depending on the findings of the most recent 结肠镜检查 and your family history.

如果检查发现息肉怎么办?

大多数类型的结肠癌发展缓慢. 在结肠内壁，生长的小细胞. 被称为 息肉，可以发展. Polyps can be flat or look like tiny mushrooms emerging from stalks.

A polyp isn’t cancer, but if not detected and removed, it can become cancerous. The transition is slow — a polyp typically grows for about 10 years before it becomes cancerous and starts to spread. Regular screening for colorectal cancer can interrupt the process.

如果结直肠癌筛查发现息肉, 你的医生可能会建议增加筛查频率.

结肠癌检查

There are several tests that can pick up signs of colorectal cancer. 两种主要类型是:

• Visual tests that allow the doctor to see the inside of the colon and rectum
• Fecal tests that examine the stool for blood or DNA markers of cancer

你的医生会为你推荐最好的筛查方法, 根据你的症状, 癌症风险和其他因素.

结肠镜检查

A 结肠镜检查 is the gold standard of colon cancer screening and the most effective way to identify this cancer. It enables the doctor to see the entire length of the lower intestine by using a flexible tube with a camera inserted through the anus. 看屏幕的时候, the doctor directs the camera through the rectum and colon to identify 息肉 and other areas of concern. Suspicious growths can be removed during the 结肠镜检查 and investigated with a biopsy.

You and your doctor may decide that a test other than a 结肠镜检查 is sufficient if you have few risk factors for colon cancer. 然而, 其他测试需要更频繁地执行, 如果结果是积极的, 你可能还需要进行结肠镜检查, 切除息肉或治疗可疑部位.

乙状结肠镜检查

就像结肠镜检查一样 乙状结肠镜检查 is a test during which a tube with a light and camera is used to view the interior of the intestine. 乙状结肠镜检查, the area examined is not the entire colon but only the sigmoid colon — the bottom third, 60%的结肠癌发生在哪里. 因为乙状结肠镜只能看到结肠的一部分, 准备工作更简单, 而且可能不需要镇静, 就像结肠镜检查一样.

乙状结肠镜检查在美国并不常见.S. 结肠镜检查, because 息肉 or colon cancer in the right colon and transverse colon can be missed during a 乙状结肠镜检查. But if a doctor believes that a patient’s symptoms are due to a problem in the lower colon alone, 他或她可能会决定乙状结肠镜检查是一个更好的检查.

钡灌肠

在一次 钡灌肠, the technologist fills the colon with barium liquid through an enema, 然后进行x光或透视(运动x光)检查. The barium helps the doctor see the inner surface of the colon and rectum, 并可能有助于识别息肉或癌变区域. A 双重对比钡灌肠 使用两种钡来获得更详细的图像. 

虚拟结肠镜检查

A 虚拟结肠镜检查 是三维的 CT扫描 that takes a detailed picture of the colon after it has been filled with air. Virtual 结肠镜检查 may be an option for people who cannot have a conventional 结肠镜检查 due to breathing difficulty, 结肠扭曲或狭窄的结肠, 出血性疾病或其他医疗问题.

This test is less invasive, does not require sedation, and takes only 15 or 20 minutes to complete. 然而，在这个测试中可能会遗漏小息肉. And if 息肉 or suspicious areas are found, a regular 结肠镜检查 可能需要 to remove them.

To guard against colon cancer, your doctor will recommend a 虚拟结肠镜检查 every five years.

粪便样本测试

The benefit of stool sample tests is that they can be performed in the comfort of your home and mailed to a laboratory for analysis. 然而，这些测试提供的信息是有限的. Stool sample tests are usually used to catch warning signs of colorectal cancer, 比如出血和某些癌症DNA标记. More testing is needed to explore the causes of 便血 or DNA abnormalities. Also, negative DNA tests don’t always prove absence of colorectal cancer. 他们可能错过8%的结直肠癌, 30% of 息肉 that will soon be cancer and 57% of 息肉 that may become cancer. 

• A 粪便隐血试验 寻找隐藏(神秘) 便血. 收集并分析了三次肠道运动的样本. Hidden 便血 can indicate colon or rectal cancer, or another problem. The tests are simple: Your doctor gives you supplies, including one or more small paper cards. 对于每个测试, 你收集一个粪便样本并把它放在一张卡片上, which is packaged and sent to a laboratory where it is tested for blood.
• A 粪便免疫化学试验 是否类似于粪便隐匿试验, 只不过没有卡片, you place the stool samples in tubes of liquid and send the tubes to a laboratory. 如果检测结果呈阳性, 更多的测试, 包括结肠镜检查, 可能需要. Your doctor may recommend a 粪便隐血试验s or a fecal immune tests each year.
• 粪便基因检测 是一种较新的粪便样本筛查方法吗. 除了验血, 实验室会寻找变异DNA的升高水平, 哪些可以预示结肠癌. A single stool sample can be collected at home and sent to a laboratory for analysis. 你的医生可能会建议每三年做一次检查.

直肠指诊

直肠指检时, 医生戴上了手套, 用润滑过的手指插入直肠，检查有无异常. The colon is about 5 feet long, so a digital rectal exam is very limited in detecting colon cancer.