Cancer of the rectum and colon (colorectal cancer) is the second leading cause of cancer deaths in the United States. Colorectal cancer is often found too late for cure. This does not always have to be the case. When found in the early stages, colorectal cancer can usually be cured by surgery. It is important for you to know the symptoms of colorectal cancer and the screening tests that can detect this cancer in its early stages before symptoms appear.
If a parent or a sibling has had colon cancer or polyps, you may be at an increased risk for a colon polyp or cancer. In this case, your doctor may want to examine your colon at regular intervals.
To detect this kind of cancer early, call your doctor immediately if you notice any of these signs of colorectal cancer:
blood in your stool
a change in your bowel movements, especially in the shape of your stool
cramping pain in your lower abdomen
a feeling of discomfort or the urge to move your bowels when there is no need.
The three main types of screening tests for colorectal cancer include:
A digital rectal exam, in which your doctor feels the inside of your rectum and colon with a gloved finger. The exam is easy and inexpensive. However, this test may be of limited value because your doctor cannot reach very far into your colon.
A lab test of a sample of your stool for traces of blood. Performing lab tests on stool samples to detect traces of blood is also relatively easy and inexpensive. However, many factors can interfere with the accuracy of these tests. Also, blood can be present for reasons other than colon cancer. Tests for traces of blood usually require further follow-up.
Flexible sigmoidoscopy. Your doctor inserts a lighted flexible instrument called a sigmoidoscope into your rectum. Your doctor looks at the lower part of your colon with the sigmoidoscope and can also take samples of tissue with this instrument for lab analysis. About half of all colorectal cancers or polyps can be seen during this exam.
Ask your doctor what tests are best for you and when you should have them done.
If you are age 40 or over, ask your doctor if you should have the digital rectal exam and how often.
Your doctor may recommend a flexible sigmoidoscopy before age 40 if you are at risk for developing colon cancer, that is, if you have a parent or sibling who had colonic polyps or cancer.
If you are over age 50, ask your doctor how often you should have a stool sample tested for blood and a sigmoidoscopy.