BLEEDING is the most common, and sometimes the only, sign of colon cancer. As a polyp or tumor grows larger, the passage of feces is likely to irritate it and cause it to bleed. However, bleeding does not always occur, and it doesn’t always mean colon cancer.
If you notice bright red blood on bathroom tissue or have bloodstains on your underwear, it is most likely from hemorrhoids or a minor tear near your anus. If your stool looks red, it may be because you’ve eaten red meat, beets or red licorice. Bleeding from polyps inside the colon may cause very dark colored stools, but is more likely to be hidden. As a result, it is detectable primarily through a test such as the fecal occult blood test.
To detect bleeding, a fecal occult blood test can be self-administered on the advice of a doctor. The test requires smearing small samples of stool, taken at different times, on a chemically treated card or pad that are then examined under the microscope. The discovery of occult blood in a specimen will usually lead the doctor to schedule a colonoscopy.
CRAMPING, PAIN: Abdominal discomfort occurs because a tumor is growing in the colon and forming an obstacle for normal movement of waste. If the tumor is large enough, it can eventually lead to nausea and vomiting.
WEIGHT LOSS: Many of us would be quite happy about losing a few pounds. Of course, if you cannot attribute it to something good you are doing, you should be suspicious. Anyone feeling constant pain in the gut is certainly not going to feel like overeating. As the pain grows, appetite wanes, and the result is weight loss.
ANEMIA: Particularly on the spacious right side of the colon, a tumor may become quite large and cause considerable bleeding before other symptoms occur. Gradual but persistent loss of blood can result in iron deficient anemia and symptoms such as fatigue, weakness, dizziness and shortness of breath. For some patients, these are the symptoms that send them to the doctor, but they are similar to symptoms caused by many other disorders. Thus the symptoms are also often overlooked.
OBSTRUCTION: On the left side, the colon is narrower. And in this part of the colon much of the water has already been removed from the stool. As a result, cancer on the left side is more likely to cause partial or complete obstruction of the bowels. Chronic constipation, often defined as having fewer than three bowel movements a week, is common among healthy individuals who are inactive and/or not eating enough fiber-rich foods. It can also be a sign of colon cancer. A partial obstruction can cause a pattern of gas and bloating. Stool and air became blocked for several days, resulting in bloating. When the blockage resolves, the air in the bowels results in persistent gassiness. When the tumor is near the end of the colon or in the rectum, the person might feel fullness or that the bowel movement has not quite been completed.
THIN STOOL: A blockage near the end of the colon sometimes results in pencil thin stools–squeezed on the way out by the tumor.
Any change in bowel habits can be a sign of colon cancer. But most individuals are a bit inhibited about discussing their bowel habits, even with a physician. And most of these signs are not dramatic enough to prompt urgent action.
The American Cancer Society recommends yearly screening with the fecal occult blood test for everyone age 50 and over and for others with risk factors such as a family history of colon cancer. Studies show that it reduces deaths from colon cancer, but the effect is small unless it is combined with other methods.
An alternative, not widely available and not covered by all insurance plans, is a stool DNA test. Instead of looking for blood, this test detects DNA markers shed by cancers or precancerous polyps. Although not perfect, it’s believed to be more accurate than the fecal occult blood test.
More thorough screening, recommended at less frequent intervals, can be performed with an endoscope or thin lighted tube to examine the lining of the colon. Sigmoidoscopy is less invasive and does not require anesthesia, as colonoscopy does. But it explores only the last two feet or so of the colon. If a polyp is found, the doctor will recommend colonoscopy to look at the entire colon and remove any polyps that are found. Both procedures are painless, but both require emptying the colon through the use of laxatives and enemas.
Virtual colonoscopy, not yet widely available, uses a CT scan to take images of the colon. Some patients might find this test attractive because it does not require that a scope be inserted into the colon. However, it still requires bowel preparation.
Another screening option, a barium enema, involves using an enema to place a contrast dye in the bowel. X-rays are then taken. This method is generally not as effective as colonoscopy in detecting polyps. And a colonoscopy is required to remove any polyps that are found, so any positive findings mean an additional procedure.
Whatever symptoms you have or don’t have, there are screening tests that allow early detection of colon cancer. Getting an early start means less discomfort and much higher chances of a full recovery.
Michelle Herbert Thomas, PharmD, CDE
Clinical Director
Richmond Apothecaries, Inc.
