Learning About Colon Cancer Can Save Your Life

by Pat DeSouza, CGRN

Pat DeSouza has over 10 years' experience in Endoscopy Nursing at St. Joseph's Medical Center, Yonkers, NY. She is a member of the Society of Gastrointestinal Nurses and Assistants and has published nursing articles on hemochromatosis and inflammatory bowel disease. Here she writes convincingly about the value of screening colonoscopy.

What exactly is the colon?

The colon, or large intestine, is a hollow, tube-like, organ that is 5 to 6 feet long and 2 inches in diameter. It consists of six sections known as the cecum, ascending, transverse, descending, sigmoid, and rectum. The wall of the colon has four layers that lie one on top of the other, much like the skins of an onion. The primary functions of the colon are the storage and movement of intestinal contents (stool) and the absorption of water and other substances essential to nutrition.

How does cancer of the colon develop?

Virtually all colon cancers begin as small growths, or polyps, that arise from the inner lining (first layer) of the colon. It is important to remember, however, that not ALL polyps have a cancerous potential. They must be checked out under a microscope once they are removed. Polyps that are pre-cancerous contain cells that have not yet turned to cancer but will do so eventually. Generally it takes a number of years for this cancerous progression to occur. This provides a window of opportunity for these pre-cancerous polyps to be taken out before they become life-threatening. Genetics seems to play the biggest role in the development of those polyps which eventually turn to cancer. Diet may have a contributing role since colon cancer is infrequent in countries with low meat intake and in Seventh Day Adventists in our Western culture who eat a vegetarian diet. A lifetime diet low in fat and high in fiber may also decrease the risk of colon cancer development.

Just how common is colon cancer in the United States?

Colon cancer is the second most common cancer in adults after lung cancer in men and breast cancer in women. Approximately 300,00 new cases are diagnosed each year and an estimated 46,500 people will die as a result of this disease in 1998. It afflicts men and women almost equally.

Are there any particular risk factors for developing this kind of cancer?

Nearly all colon cancers begin as noncancerous growths called polyps.

Colon cancer can even occur in young adults, as witnessed by the recent discovery of this disease in the Yankee ballplayer, Darryl Strawberry. The risk becomes greatest, however, in people over the age of 50. This risk takes off and gets higher as the age increases. In fact, one study showed that at least 57% of the population will have a colon polyp by the age of 70 (but remember, not all of these polyps are necessarily pre-cancerous). If an individual has any of the following risk factors, his or her chances of getting colon cancer increases as does the possibility of getting it under the average risk age of 50:

What are the signs and symptoms of colon cancer?

As previously mentioned, there really aren't any early signs of polyps or colon cancer. Usually by the time an individual notices signs and symptoms, a cancer has already developed. The symptoms may not be a predictor as to how advanced the cancer is. If the cancer is found before it has penetrated too many layers of the colon (remember the onion), or has reached the lymph nodes or other parts of the body, the chance of cure is greater. Some of these symptoms may include things like a change in bowel habits (narrow stools or a new onset of constipation), blood in the stool, fatigue, or abdominal pain. These symptoms, in and of themselves, do not mean that colon cancer is present. They do indicate that further investigation by a doctor is necessary.

How can an individual protect himself or herself from getting colon cancer in the first place?

Most colon cancers are preventable.

The great news about colon cancer lies in the answer to this question. It is totally preventable in 90% of the cases! Just imagine that this type of cancer could be almost completely obliterated if everyone was proactive in taking care of the colon. Everyone over the age of 40 should have a rectal examination done every year by his/her physician. The purpose of this exam is to check for the presence of masses in the rectum and to obtain a small smear of stool that can be tested for occult blood (blood that can't be seen by the eye but which shows up when a chemical solution is applied to it). After the age of 50, the American Cancer Society recommends the addition of a flexible sigmoidoscopy (see below) every 5 years. There are some controversies about the occult blood test and the flexible sigmoidoscopy, however. The occult blood test will only pick up, at very best, 30% of those who have cancer in the colon. That means that it will go undetected in 70% who have it. In addition, the flexible sigmoidoscopy only examines the lower third of the colon. If polyps are found in the lower third, then a full examination of the colon, called a colonoscopy, will be done. A debate exists among the experts as to whether polyps or cancer could be present in the ¾'s of the colon not seen on the flexible sigmoidoscopy exam when no polyps or cancers are seen in the lower third. The ASGE (a professional organization of gastrointestinal specialists) has suggested that the gold standard for detection of colon cancer in all six parts of the colon is the colonoscopy. Every individual should have this test done upon reaching the age of 50. It may be necessary to do this at an earlier age if there is high risk, or if the presence of symptoms suggest a possible colon cancer.

Is a colonoscopy a difficult examination? How is it done?

Colonoscopy sounds worse than it is.

A colonoscopy is a relatively simple examination of the entire length of the colon using a flexible tube with a small camera chip at the end. An image of the inside of the colon is projected in clear, living color onto a television screen for the gastroenterologist (doctor specializing in the colon and this exam) to view. As the tube is advanced by the doctor, small amounts of air are instilled in the colon so that the walls (ordinarily collapsed until stool comes along to expand them) can be opened up for visualization and safe progression of the colonscope. The exam takes approximately 20 minutes to complete. An intravenous needle is placed into a vein in the arm prior to starting so that medications can be given to make the patient sleepy and comfortable. In the majority of cases, most people don't even remember the test. They are often amazed to hear us tell them that the colonoscopy has been completed! During the entire time, a nurse monitors the patient's blood pressure, heart rate, and breathing and makes sure that the patient is very comfortable.

Is there any special preparation for the test?

Yes. The colon must be cleansed the evening prior to the examination so that no stool is left behind that would prevent the doctor from seeing the inside layer. Instructions regarding what type of laxative, and how to take it, should be given to each patient by the gastroenterologist when the examination is scheduled. Certain dietary restrictions are necessary such as not eating solid foods after a certain time the day before and then drinking only certain types of liquids thereafter. Nothing is generally supposed to be taken after midnight. The doctor will also let you know how to manage your medications, if you are taking any. Because of the fact that sedation is given for the exam, the patient should not drive home that day but should have an escort available to take him.

Are there any risks involved with a colonoscopy?

Even safe tests have some risks.

Millions of colonoscopies are performed by trained gastroenterologists every year without any problems. The examination is generally considered to be extremely safe. As with any procedure, there is always a small risk of complications. The greatest risk of these procedures comes from the sedation given, rather than the test itself. Careful monitoring and judicious use of the medications greatly limits this occurrence. There is a remote possibility that a small tear, or perforation, could occur in the wall of the colon from the colonscope or as a result of a polyp removal procedure. In addition, some bleeding could occur after a polyp is removed. Again, these complications are more the exception than the rule. The benefit of the colonoscopy greatly outweighs the very small risks involved.

When will the results of the colonoscopy be available?

The doctor will be able to report whether a polyp or a possible cancer has been detected immediately. If a polyp is found, it is usually removed during the colonoscopy while the patient is sedated. The polyp removal is not painful since the lining of the colon does not have the same nerve endings as those on the outer skin that respond, with pain, to cutting etc. The polyp is then sent to the laboratory for examination under the microscope by a specialist in this area. The results regarding the type of polyp will be available in 3 to 5 days. If a suspected cancer is seen during the colonoscopy a biopsy, or small sample of that tissue, will be taken and sent to the laboratory.

Will a future colonoscopy ever be necessary?

The doctor will decide, based on his findings of the exam, when and if another colonoscopy is necessary. If polyps were found, a follow up colonoscopy will be recommended generally within 1 to 3 years, depending on the type of polyp found. Remember, if polyps were found, there is an increased chance more will grow in the future. Continuing to have a screening colonoscopy, as recommended, will prevent colon cancer from ever occurring.

What if a colon cancer is found on colonoscopy?

If a colon cancer is found and confirmed by the biopsy results, the doctor will discuss with the patient the best treatment approach for his/her particular situation. Surgery is usually done to remove the area of the colon in which the tumor (cancerous polyp) was found. The prognosis (or chance of complete cure) will depend on how advanced the cancer was at the time it was discovered (how many layers of the colon were involved and if it spread outside the colon to other organs). Depending on how advanced the cancer is, chemotherapy is sometimes used to improve the chance of cure. This very individualized advise would come from the physician to his/her patient.

If colon cancer is so preventable, why is it still so common?

Embarrassment stops many people from getting checked.

This may well be the best question of all. It is sad to see how little attention is given to colon cancer and its prevention. Not until a celebrity is afflicted with the disease does the media put the word out to the general public. More aggressive education is necessary at all times. Many people, aside from being ignorant about colon cancer, may fear the examination or be embarrassed about the body part involved. As Katie Couric of the Today Show, whose husband recently died at 42 of colon cancer, said: "I think we have to use the words, say them. Colon. Rectum. Bowels. The more matter of fact you are with the language, the more it helps. You can't be squeamish about it. It might cost you your life".

Curious about colonoscopy? Write to Pat Desouza, RN. She promises to do her best to answer your questions!


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