Cancer of the colon is a major health problem in the United States. It ranks as a leading form of cancer, along with lung and breast cancer. Importantly, colon cancer is also one of the most curable forms of cancer. When detected early, more than 90 percent of patients can be cured.
This disease begins in the cells that line the colon. There now is strong medical evidence that there are abnormal genes for colon polyps and cancer that can be passed from parent to child. The genes within each cell are the hereditary structures that tell the cell what it should do. It is becoming increasingly clear that certain of these genes control the growth of the cells on the lining of the colon. When these controlling genes are absent there is a tendency to grow polyps. The cells in the polyp eventually become uncontrolled and turn into a cancer. Colon cancer also can develop from other conditions, such as ulcerative colitis, a chronic inflammation in the colon.
What is a Colon Polyp?
A polyp is a growth that occurs in the colon and other organs. These growths, or fleshy tumors, are shaped like a mushroom or a dome-like button, and occur on the inside lining of the colon. They may be as small as a tiny pea or larger than a plum. It is important to note that while colon polyps start out as benign tumors, some polyps, in time, become malignant. In fact, the larger the polyp, the more likely it is to contain cancer cells. In most cases, it is a polyp called an adenoma polyp that develops into colon cancer.
What are the Risk Factors For Developing Colon Polyps and Cancer?
An individual whose parents, brothers or sisters have colon cancer is at increased risk. In addition, certain unusual conditions, such as hereditary polyposis, lead to colon cancer 100 percent of the time. Persons living and eating in Western societies are exposed to certain factors that are detrimental to the bowel. Medicine is just beginning to learn about these. Also, females who have had genital or breast cancer are at an increased risk of developing colon cancer. Ulcerative colitis, after a long time, also can lead to colon malignancy.
Why Do Polyps Form?
As noted above heredity is probably the most important factor. The absence of a controlling gene within the cells is most likely a necessary event.
Other facts are known. Rural residents in Africa and India rarely develop colon polyps or cancer. Their diets are high in unprocessed grains (bran) and low in meat. Diets that are high in bran and roughage produce bulky stools that have a lower bacteria count. Further, it is known that animal fat in meat, when broken down by the body's intestinal juices, may change into certain compounds termed carcinogens. These compounds cause colon cancer in laboratory animals. When residents in developing countries eat a Westernized diet of meat, low roughage and refined grains, over time they develop the same incidence of colon polyps and cancer as people living in the Western world. So diet probably plays an important role in causing colon cancer.
Three Categories of Polyps
Enough is now known about polyps that physicians generally place patients in one of three categories. In each of these the end result is an adenoma type polyp:
The key to early detection of colon polyps and cancer is the concern and willingness of each person to seek medical attention from a physician. The physician will perform the following:
How are Polyps Removed?
Removal of colon polyps reduces the risk of subsequent development of cancer of the colon. Polyps are usually removed using a colonoscope, which allows the physician to visualize the inside of the colon. Biopsy equipment and snares (wire loops) are passed through the endoscope and, with electrical heat (electrocautery), remove polyps and small tumors. This procedure is performed in the outpatient setting under sedation.
Cancer of the colon is a serious but readily detected malignancy. Early detection promises a particularly high chance of survival. Most colon cancers start as polyps, which can usually be removed through a colonoscopic exam. Today, there is much that can be done to prevent and cure this cancer. The essential first step involves action by the patient.