Colon Polyps and Cancer
Cancer of the colon ranks as a leading form of cancer, competing with lung and breast cancer and is a major health problem in the United States. It is also one of the most curable forms of cancer and when detected early has a 90% and plus of success in terms of cure.
Strong medical evidence points towards abnormal genes for the development of colon polyps and cancer in the cells of the colon lining and that these genes have a hereditary basis (can be passed from parent to child). Genes are the hereditary units within each cell that program the cells functions. When these controlling genes are absent there is a tendency towards formation of polyps. The cells in the polyp eventually attain an uncontrolled cancerous growth. Ulcerative colitis or a chronic inflammation in the colon are the other possible conditions contributing towards colon cancer.
Colon Polyp/Cancer
The colon is the large intestine. It begins where the small intestine ends, near the appendix inside the right lower abdomen. The colon extends in a wide loop, up the right side of the abdomen to the liver, and across to the left side of the abdomen where it turns down connecting finally to the rectum.
Polyps are fleshy tumors mushroom-shaped growths that occurring in the inner lining of colon and other organs. Their size may range from that of a tiny pea to a large plum. Colon polyps start out as benign tumors but in time may become malignant. 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.
Risk Factors
- Family history of polyps, cancer and especially, colon cancer
- Western civilization and diet
- Being over 40 years of age
- History of breast cancer
- Ulcerative Colitis
- In addition, certain unusual conditions, such as Hereditary Polyposis, lead to colon cancer 100 percent of the time.
- 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.
Formation
For the vast majority of polyps, dietary and genetic influences may be of equal importance.
Factors
- Heredity and genes - The absence of a controlling gene within the cells is most likely a necessary event. Certain family histories indicate heredity plays a key role. Certain genes seem to prevent colon cancer from developing. Some people may lose these protective genes. A person whose parents, brothers or sisters have colon cancer or polyps is at significantly greater risk of developing it. There is also risk, but to a lesser degree, if uncles, aunts or grandparents have had the disease. Therefore, people with a family history of polyps and colon cancer should be evaluated by their physician and examined regularly. Hereditary Familial Polyposis and Lynch Syndrome are two such disorders that are clearly linked to genes alone.
- Diet
- Free radicals are natural byproducts of normal metabolism which cause damage to the body. Fruits and vegetables have great quantities of antioxidants, chemicals that counteract and neutralize the free radicals. Animal foods do not contain antioxidants. People following a diet rich in fruits and vegetables have lower incidence of cancers . There fore it is recommended to eat five portions of colorful fruits and/or vegetables each day. Vitamin C, E and betacarotene supplements have not been shown to prevent any cancer. Diets 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.
- Calcium Medical studies are showing that people who get 1000-1500 mg of calcium a day in their diet have less incidence of colon cancer. This level of calcium (from milk, dairy products, vegetables or supplements) is currently recommended for healthy bones. Calcium is some way regulates the growth of the cells that line the inside of the colon and hence benefit it.
- Meat and saturated fat Saturated fat may be broken down in the body to carcinogens which, at least in animals, can lead to colon cancer.
- Fiber Recent analysis revealed that foodstuffs high in fiber do not by themselves prevent colon cancer by the high quantity of fiber makes the passage of stool easy preventing other conditions like fissures, abscesses and fistula. However, most fruits and vegetables are high in fiber and also contain beneficial chemicals called antioxidants.
Categories of Polyps
On the basis of information available polyps can be categorized into three and in each of these the end result is an adenoma type polyp:
- The Ordinary Polyp - Most sporadic polyps occur between the ages of 40 and 60. There may be only one or two present and they may take ten years or more to develop into a cancer. There is a hereditary link. Eventually some of these become cancer.
- Hereditary Familial Polyposis - This is a true hereditary condition in which the entire colon is studded with hundreds, even thousands of polyps. They begin at a very early age even under ten years old. Virtually every patient will eventually develop colon cancer. The only known preventive treatment is surgical removal of the colon. Fortunately, the condition is not common.
- Lynch Syndrome (Hereditary Non - Polyposis Colorectal Cancer) - This disorder is more common than Familial Polyposis but less than the ordinary polyp. There is a strong tendency for adenoma type polyps to occur in close blood relatives. More polyps are seen and at an early age and so is the cancer. In some families there is also an increased incidence of breast, ovarian, and other cancers. So a family history of this type warrants very close surveillance of all direct blood relatives.
Detection
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 generally will perform the following:
- Medical history - The patient's medical history will identify the presence of risk factors for colon polyps and cancer.
- Stool exams to detect occult (hidden) blood - Colon cancers and large polyps may shed minute quantities of blood so examination of the stool for occult blood is an important exam.
- Sigmoidoscopy - This is a visual exam of the rectum and lower colon using a lighted, flexible Endoscope. It allows for the direct detection of colon tumors.
- Colonoscopy - This procedure examines the entire 5-6 foot long colon. The exam is usually done under sedation. It is really the definitive exam since colon polyps can be discovered and removed at the same time.
- Barium Enema - This x-ray exam is an older exam which, at times, is still useful. Barium flows into the colon and x-rays are taken which then can outline the shadows of polyps and cancer. Polyps cannot be removed by this technique.
- Virtual Colonoscopy - This test is still in the experimental stage. Early studies indicate that it does not pick up small polyps very well. Furthermore, like barium enema, polyps can not be removed even when they are found.
Polyp Removal
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.
Prevention of Colon Polyps and Cancer
Since your genes cannot be changed, if there is a family history of colon polyps or cancer, a Colonoscopy should be performed to remove the polyps before they become malignant. Calcium and aspirin may have a protective role. Ask your physician about taking a calcium supplement and/or aspirin. While dietary fiber and regular exercise are not clearly protective, they play a real role in promoting long-term good health.
While colon polyps start out as benign tumors, certain types of polyps (called an adenoma or adenomatous polyp) may turn into cancer. The risk is greater as the polyp gets larger. Adenomatous polyps can be removed before they become cancerous with a procedure called Colonoscopy. Under light sedation, a lighted flexible tube is inserted into the colon, allowing the physician to see the inside of the colon and remove polyps.
- Diet - It only makes sense that a disease that originates in the gut should somehow be related to diet. While genetic factors are probably the most important, let's look at the effects of diet.
- Vegetables and fruits - The red, yellow, orange and green colored fruits and vegetables such as peppers, oranges, strawberries, and carrots are particularly rich in a complex mixture of substances called antioxidants. The cruciferous vegetables (cabbage, Brussels sprouts, broccoli, cauliflower) have very high levels of natural cancer fighting chemicals. Brussels sprouts and broccoli are exceeding high in these. There is increasing medical data that people who eat these foods plus generous amounts of unprocessed grains have less colon cancer. There is no medical evidence that taking antioxidant supplements such as vitamin C and E and beta carotene is helpful.
- Folic Acid - Data was published in 1999 which studied a large group of nurses over a 14 year period. Folic acid or folate seemed to be very protective for these females especially those who received over 400 micrograms a day from food and/or a multivitamin. It may also be of benefit in colon cancer prevention.
- Meats and saturated fats - Meat contains saturated fat as do many prepared products such as ice cream and especially non-animal foods such as pastries, sauces, etc. Always read the food labels to see how much saturated fat a food contains. These fats are broken down by the body's digestive juices and bile. Some of these byproducts are known to cause cancer in laboratory animals. There is some evidence that meat rich diets may increase the risk of breast cancer but this has not been shown in colon cancer. Nevertheless, a reduced meat and saturated fat diet probably contributes to colon health to some extent.
- Fiber - Studies in the 1960's and 1970's seemed to relate a fiber rich diet with reduced colon cancer in rural Africans. However, the hope that it could reduce colon cancer risk has been called into question by a large study of nurses who had little or no change in developing colon cancer or polyps even when eating up to 25 grams of fiber a day. This is just one study and the positive health benefits of high fiber foods are many, so these foods are still highly recommended.
- Calcium - Calcium is one of the most common minerals in the body. It is necessary for bone strength and for many of the body's important chemical processes. For example, it is needed in regulating the growth of cells. Animal studies have found that a lack of calcium leads to excessive cell growth in the colon. It is not clear if calcium has a cancer preventive benefit for humans. Still, since it is important to the body in so many other ways, everyone should get enough calcium in their diet. All adults should have 1000 mg per day. After menopause, females have a greater risk of osteoporosis (loss of calcium causing bones to weaken), and they should have 1500 mg of calcium a day. A quart of milk a day provides adequate calcium. Most people do not drink a quart of milk everyday, but there are other sources of calcium. Dairy products (such as cheeses and yogurt), shellfish, seafood and many leafy green vegetables contain calcium. The calcium in leafy vegetables is not as available for use by the body as calcium in milk. Some people on low calorie or special diets may not be able to get enough calcium in their diets. In these cases, the physician can recommend a calcium supplement. Calcium carbonate is the best and least expensive.
- Aspirin - Some, but not all, medical studies show that the incidence of cancer of the colon may be less in those people who take aspirin regularly. It is known that prostaglandin (a hormone-like substance produced by the body) may promote excessive or abnormal cell growth in the intestine. Aspirin appears to interfere with prostaglandin which may account for a possible role in preventing colon cancer. Aspirin can cause stomach ulcers, serious bleeding or hemorrhagic strokes, so it should only be taken with the approval of a physician.
- Other Factors - The large nurse's study, mentioned before, has shown other factors that appear to be related to colon cancer.
- Cigarette Smoking - long-term smokers had more colon cancer than non-smokers.
- Leisure Time Activities - those nurses who were more active in their daily lives had fewer cancers.
- Estrogen - those nurses who continued to use estrogen hormones had fewer cancers. However, it is not recommended that you take estrogen just for this possible reason.
Summary
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.
- Genes - if there is colon cancer or polyps in your family, have a Colonoscopy to detect early cancer or removal of polpys.
- Surveillance - yearly stool exam for hidden blood and Sigmoidoscopy (short exam) every 5 years or Colonoscopy every 10 years or so, starting at age 50.
- Polyps - remove polyps when found, a polyp that is removed cannot become cancer.
- Diet - eat a diet high in yellow, red and orange fruits and vegetables, low in meats and saturated fats and high in fiber.
- Calcium - 1000 to 1500 mg a day from diet or supplements.
- Folic Acid - take a daily supplement or multivitamin with at least 400 mcg of folic acid.
- Aspirin - may be helpful but should be discussed with physician.
- Lifestyle - keep an active lifestyle - walk, exercise.
- Cigarettes - do not smoke cigarettes.
- Estrogen hormones - discuss with physician.