如何筛查大肠癌

肠癌筛查（Colon Cancer Screening）
Colon cancer (cancer of the large bowel) is the second leading cause of cancer deaths in the United States, exceeded only by lung cancer. Colon cancer can be treated and often cured if it is found early. Because death from colon cancer is preventable, doctors want to look for colon cancer before it grows too large or spreads to other organs. Testing persons without symptoms or signs of colon cancer (such as blood in the stool or low blood count) is called screening. Screening for colon cancer is recommended for everyone aged 50 years and older.
结肠癌（大肠癌）在美国是引起死亡的第二大肿瘤，仅次于肺癌。结肠癌可以治疗，如果在早期可以治愈。因为结肠癌引起的死亡是可以预防的，所以医生希望在肿瘤长得太大或者扩散到其他器官之前发现结肠癌。对没有结肠癌相关症状或体征的人群进行检查（比如检查大便里的血或低血细胞计数）就叫做“筛查”。推荐所有50岁或以上的人都进行结肠癌筛查。

METHODS FOR SCREENING 筛查方法
？ Fecal occult blood test
大便潜血检查
Colon cancer can cause a small amount of occult (not visible) bleeding. Testing for this occult blood involves placing a small sample of feces on a card and then adding a chemical solution. If the result indicates the presence of occult blood, further testing is required to determine the source of bleeding. This test is simple to perform but will not detect all colon cancers.
结肠癌可能导致少量的隐形出血（肉眼看不出）。检查隐形出血的方法是把少量的粪便放在卡片上，然后加入化学溶液。如果结果显示有隐形出血，那就需要进一步检查寻找出血的来源。这个检查简单，但并不一定能够检查出结肠癌。

？ Flexible sigmoidoscopy
乙状结肠镜
The sigmoid colon is the lowest part of the colon, near the rectum (the last several inches of the large bowel). Sigmoidoscopy is the placement of a lighted tube into the rectum after enemas to cleanse the lower part of the bowel. This tube is gently moved forward into the sigmoid colon. The walls of the sigmoid colon are then examined for abnormal growths.
乙状结肠是结肠的最末端部分，靠近直肠（大肠的最后一段）。乙状结肠镜就是在用灌肠的方法清洗大肠最后一段后，把带光源的管子伸入直肠，再往前轻轻进入乙状结肠，就可以看到乙状结肠的肠壁是否长了异常的东西。

？ Colonoscopy
结肠镜
If your doctor recommends colonoscopy (for screening or if growths are foundon sigmoidoscopy), you will consume only clear liquids and take laxative solutions to cleanse your intestinal tract (bowels) during the day before the procedure. Colonoscopy is not painful but is uncomfortable enough that you may require sedative medication during the procedure. The doctor will insert the colonoscope (a lighted tube with a camera on the end) through your rectum while you rest on your side. The camera will display its picture on a monitor screen. The colonoscope is gently pushed forward through as much of the colon as possible. If the doctor finds any suspicious areas in the colon, biopsies (tissue samples) may be taken. Colon polyps (small growths) can also be removed through the colonoscope.
如果您的医生建议做结肠镜（为了筛查或者乙状结肠镜发现长了异常的东西），你需要在检查前进食流质以及服用泻药，把小肠清洗干净。结肠镜其实并不痛苦，但可能不太舒服，检查过程中可能用到镇静药物。医生会在您侧躺的时候把结肠镜（带有光源的、一端有摄像头的管子）伸进直肠。摄像头拍摄的图片会在外接的显示屏上看到。结肠镜轻轻推进，尽量不断进入结肠的最深处。如果医生发现任何可疑异常，就可能进行活检（组织样本）。通过结肠镜还可以切除结肠息肉。

？ Barium enema
钡灌肠
a type of x-ray procedure that requires preparation similar to that for colonoscopy.
是一种X光的检查方法，准备方法类似肠镜检查。