Based on the community health assessment from 2014 for the Three Rivers District, cancer alone is the number one cause of death in our district. Second to lung cancer, colon cancer is the second leading cause of cancer deaths and also one of the most preventable types of cancer. More than half of all colon cancer cases could have been prevented by regular screening.
What is Colon Cancer?
Most colorectal cancers start as a polyp – a growth that starts in the inner lining of the colon or rectum and grows toward the center. Most polyps are not cancer. Only certain types of polyps (called adenomas) can become cancer. Taking out a polyp early, when it is small, may keep it from becoming cancer.
Over 95% of colon and rectal cancers are adenocarcinomas. These are cancers that start in gland cells, like the cells that line the inside of the colon and rectum.
To learn more about what colon cancer is visit http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-what-is-colorectal-cancer.
While the exact cause of colon cancer is unknown, there are certain known risk factors. A risk factor is something that affects a person's chance of getting a disease. Having a risk factor, or even several, does not mean that you will get the disease. Some people who get colorectal cancer may not have any known risk factors. Even if a person with colorectal cancer has a risk factor, it is often very hard to know what part that risk factor may have played in the development of the disease. Colon cancer will strike 1 in 20 and both men and women are at equal risk. People with a family history of colon cancer are at higher risk and should begin screening at a younger age.
Risk factors you cannot change
Risk factors linked to things you do
- Age: your risk gets higher as you get older
- Having had colorectal cancer or certain kinds of polyps before
- Having a history of ulcerative colitis or Crohn’s disease
- Family history of colorectal cancer
- Race or ethnic background, such as being African American or Ashkenazi
- Type 2 diabetes
- Certain family syndromes, like familial adenomatous polyposis (FAP) or hereditary non-polyposis colon cancer (HNPCC, also called Lynch syndrome)
- Some lifestyle-related factors have been linked to a higher risk of colorectal cancer.
- Certain types of diets: one that is high in red meats (beef, lamb, or liver) and processed meats (like hot dogs, bologna, and lunch meat) can increase your colorectal cancer risk.
- Cooking meats at very high heat (frying, broiling, or grilling) can create chemicals that might increase cancer risk.
- Lack of exercise
- Being very overweight (or obese)
- Heavy alcohol use
Signs and Symptoms
- Colorectal cancer may cause one or more of the symptoms below. If you have any of the following you should see your doctor:
- A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
- A feeling that you need to have a bowel movement that is not relieved by doing so
- Rectal bleeding
- Blood in the stool which may make it look dark
- Cramping or abdominal (belly) pain
- Weakness and fatigue
- Unintended weight loss
Colorectal cancers can bleed. While sometimes the blood can be seen or cause the stool to become darker, often the stool looks normal. The blood loss can build up over time, though, and lead to low red blood cell counts (anemia). Sometimes the first sign of colorectal cancer is a blood test showing a low red blood cell count.
Most of these problems are more often caused by conditions other than colorectal cancer, such as infection, hemorrhoids, irritable bowel syndrome, or inflammatory bowel disease. Still, if you have any of these problems, it's important to see your doctor right away so the cause can be found and treated, if needed.
If there is no family history or symptoms of colon cancer, screening should begin at age 50 with a colonoscopy. For this test, the doctor looks at the entire length of the colon and rectum with a colonoscope, a thin, flexible, lighted tube with a small video camera on the end. Special instruments can be passed through the colonoscope to biopsy (sample) or remove any suspicious-looking areas such as polyps, if needed. Colonoscopy may be done in a hospital outpatient department, in a clinic, or in a doctor’s office. A colonoscopy should be done every 10 years, unless otherwise recommended by your physician.
Between colonoscopies, at home screening tests should be performed through the age of at least 74 in order to keep an eye out for any signs of colon cancer that may develop.
Guaiac-based fecal occult blood test (FOBT)
Since 10 years can be a long interval to wait to be screened for colon cancer, there are other tests that can be done in between routine colonoscopies. One test is the guaiac-based fecal occult blood test (gFOBT) which detects blood in the stool through a chemical reaction. This test is conveniently done in the comfort of your own home, but cannot tell if the blood is from the colon or from other parts of the digestive tract. If this test is positive, a colonoscopy will be needed to find the reason for the bleeding. Although cancers and polyps can cause blood in the stool, other causes of bleeding can occur, such as ulcers, hemorrhoids, diverticulosis, or inflammatory bowel disease.
The fecal immunochemical test (FIT)
Another option is the fecal immunochemical test (FIT), which also tests for occult (hidden) blood in the stool in a different way than a guaiac-based test. This test reacts to part of the human hemoglobin protein, which is found in red blood cells. The FIT is done essentially the same way as the FOBT, but some people may find it easier to use because there are no drug or dietary restrictions and sample collection may take less effort. This test is also less likely to react to bleeding from parts of the upper digestive tract, such as the stomach.