Colon and rectal polyps are small growths that project out from the inside lining of the large intestine or rectum. They usually are noncancerous and produce no symptoms. However, some polyps can turn into cancer. Polyps that turn into cancer typically take several years to do so. Screening for colon cancer allows polyps to be detected and removed early, which may prevent the development of cancer.
Your body absorbs nutrients and removes waste products via your digestive system. Whenever you eat and drink, food travels through your digestive system for processing. As water from the waste product is absorbed, the product becomes more solid and forms a stool or feces. It is eventually eliminated from your body when you have a bowel movement.
After you swallow food, it moves through your esophagus and into your stomach. Chemicals in your stomach break down the food into a liquid form. The processed liquid travels from your stomach to your small intestine. Your small intestine breaks down the liquid even further so that your body can absorb the nutrients from the food you ate. The remaining waste products from the small intestine travel to the large intestine.
Your large intestine, also called the large bowel or colon, is a tube that is about 5 feet long and 3 or 4 inches around. The lower GI tract is divided into sections, including the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal, and anus. The appendix is located on the cecum, but it does not serve a purpose in the digestive process.
The first part of the colon absorbs water and nutrients from the waste products that come from the small intestine. As the colon absorbs water from the waste product, the product becomes more solid and forms a stool. The large intestine moves the stool into the sigmoid colon, where it may be stored before traveling to the rectum. The rectum is the final 6-inch section of your digestive tract. No significant nutrient absorption occurs in the rectum or anal canal. From the rectum, the stool moves through the anal canal. It passes out of your body through your anus when you have a bowel movement.
A polyp is a small growth that projects out from the inner mucus lining of the colon or rectum. Most polyps are noncancerous. Polyps that turn into cancer typically take several years to do so. A hyperplastic polyp is generally noncancerous but can be of concern if it grows large. An adenoma is a type of polyp that can turn into cancer. Cancer of the cells that line the inside of the colon is called adenocarcinoma. Adenocarcinomas are the most common type of colon cancer.
The exact cause of colon cancer is unknown. Cancer occurs when cells in the interior lining of the colon grow abnormally and out of control, instead of dividing in an orderly manner. Some people may inherit a genetic variation cannot control the division of cells in the colon and promotes the growth of polyps and cancer. Polyps that may be associated with certain hereditary disorders include Gardner’s Syndrome, Peutz-Jeghers Syndrome, Juvenille Polyposis, Familial Adenomatous Polyposis, and Lynch Syndrome.
Most people with colorectal polyps or early colorectal cancer do not have symptoms. Symptoms may include changes in bowel movement patterns. You may develop diarrhea, constipation, or narrow stools that last for more than a few days. You may experience rectal bleeding or have blood in your stools. However, it is also common for the stools to remain normal looking. Lower abdominal pain or cramps are rare but may occur. Weight loss may occur for no apparent reason. You may feel weak or tired. Additionally, some people develop anemia, a condition characterized by a decrease in red blood cells.
Your doctor can diagnose colon polyps after reviewing your medical history and by conducting a physical examination. You should tell your doctor about your symptoms and risk factors. Your doctor will rule out other conditions with similar symptoms, such as hemorrhoids or infection. There are several tests for colorectal polyps.
Your doctor will examine your abdomen to feel for growths or enlarged organs. Your doctor may also perform a digital rectal examination. To do so, your doctor will briefly insert a gloved, lubricated finger into your rectum to check for a growth or mass. A mass may be indicative of rectal cancer, but not colon cancer.
A stool blood test can detect small amounts of blood in your stool. The fecal occult blood test (FOBT) or the fecal immunochemical test (FIT) is commonly used. You will receive a kit and instructions for taking a stool sample at home. The kit is sent to a laboratory for testing. If the test results are positive, your doctor may order a colonoscopy to identify the exact cause of bleeding.
A flexible sigmoidoscopy is used to view the rectum and part of the colon for cancer or polyps. A sigmoidscope is a thin tube with a light and viewing instrument. It is about two feet long. The sigmoidscope is placed in the colon, through the anus. This test can be uncomfortable, but should not be painful. Any abnormal results are followed up with a colonoscopy.
A colonoscopy is used to view the entire colon. A colonoscopy is similar to a sigmoidoscopy, but it is much longer. A colonoscopy allows a doctor to examine the colon for cancer or polyps. A tissue sample or biopsy can be taken with the colonoscopy. A colonoscopy can be uncomfortable, and you will receive medication to relax you prior to and during the test.
A virtual colonoscopy is a newer way to view the colon with a computed tomography (CT) scan. A CT scan takes a series of images to compose a detailed picture. A virtual colonoscopy involves filling the colon with air and then taking the CT scans. The CT images construct a visual depiction of the interior of the colon. The colon can also be viewed with a barium enema with air contrast test. For this test, the barium, a chalky substance, and air are used to fill and expand the colon. Next, X-rays are taken. These tests can be uncomfortable. Any abnormal results are followed up with a colonoscopy.
Tissue from polyps can be sampled or even removed and then examined to see if they are cancerous. Most polyps are removed during a colonoscopy. In rare cases, a section of the colon may be surgically removed if the polyps are cancerous. Early detected cancer has excellent cure rates. People found to have polyps are then examined on a regular basis, usually every three to five years.
In most cases, colon cancer is treatable if it is detected early. The American Cancer Society recommends that people be screened for colon cancer beginning at age 50. Screening may be warranted earlier for people with a history of polyps or inflammatory bowel disease and a personal or family history of certain cancers. Screening may include fecal occult blood testing, flexible sigmoidoscopy, colonoscopy, and barium enema testing. Some studies suggest that lifestyle changes may be helpful as well in the prevention of colon and rectal cancer. This includes not smoking and maintaining a healthy weight. These studies are not conclusive, but they suggest that eating fruits and vegetables that are high in fiber and reducing high-fat foods may reduce the risk of colorectal cancer. Other studies suggest that vitamins or a diet containing folic acid or folate, vitamin D, magnesium, and calcium may help lower colorectal cancer risk. Exercising for 30 minutes for five or more days during the week is also recommended. Aspirin and similar medications may help reduce polyp formation in some people. However, not everyone can tolerate the side effects of aspirin. You should talk to your doctor before taking aspirin to see if it is right for you.
Am I at Risk
Certain risk factors may increase your likelihood of developing colorectal polyps. People with all of the risk factors may never develop polyps; however, the chance of developing the condition increases with the more risk factors you have. You should tell your doctor about your risk factors and discuss your concerns.
Risk factors for colorectal polyps:
_____ People over the age of 50 are more likely to develop colorectal polyps.
_____ If you had colorectal polyps or cancer before, even if it was removed, you are at risk for developing colorectal polyps or cancer again.
_____ Ulcerative colitis and Crohn’s Disease increase the risk for colon polyps.
_____ If you have family members that have colorectal polyps or cancer, especially before the age of 60, you are at a higher risk.
_____ Certain genetic syndromes in some families cause the development of hundreds of polyps in the colon. The high number of polyps increases the risk of developing cancer.
_____ What you eat may increase your risk for colon cancer, although the cause of the link is not clear. Diets that are low in fiber, high in fat and animal products, such as meat, appear to increase the risk of colorectal polyps and cancer.
_____ People who are overweight have an increased risk of developing polyps and a higher rate of dying from colorectal cancer.
_____ People who smoke are more likely than non-smokers to develop polyps and die of colorectal cancer.
The majority of colon cancers begin as a benign or non-cancerous polyp. Polyps that turn into cancer typically take several years to do so. Screening for colon cancer allows polyps to be detected and removed early, which may prevent the development of cancer.