Colorectal cancer is one of the most common cancers in the world.
What is cancer?
Our body consists of cells. Normal cells grow, multiply and die in an orderly manner and are replaced by new cells. Cancer cells do not die and continue to multiply in a disorderly manner. Over time they can form a mass which may be malignant, in other words cancerous.
What is colorectal cancer?
Colorectal cancer develops when this process occurs in the lining of the large intestine. This type of cancer often develops slowly over a period of years and usually starts as a non-malignant polyp.
Where is the large intestine?
Together the colon and rectum form the large intestine, a large tube that is part of the digestive system. The job of the large intestine is to store and remove solid waste from the body.
What increases my risk?
A RISK FACTOR increases the likelihood that you will develop a disease. Having a risk factor does not mean that you will develop a disease. Different cancers have different risk factors. Risk factors for colorectal cancer include:
Age – Risk increases with age. Most people who get colorectal cancer are over age 50.
Polyps – Polyps are abnormal growths that are usually non-cancerous but may over time become cancerous.
Personal History – A person who has already had colorectal cancer is at increased risk of developing it again.
Women with a history of ovarian, uterine or breast cancer have an increased risk of developing colorectal cancer.
Family History – Having a father or mother, brother or sister, son or daughter diagnosed with colorectal cancer will increase a person’s risk of developing colorectal cancer particularly if the relative was diagnosed at an early age.
Inflammatory Bowel Disease – Medical conditions that result in chronic inflammation of the lining of the colon including ulcerative colitis and Crohn’s disease.
Inherited disorders – Certain inherited medical conditions including familial adenomatous polyposis (FAP) and hereditary non-polyposis colon cancer (HNPCC)
Diet – Research suggests that eating a diet high in red and processed meats and low in whole grains, fruits and vegetables may increase the risk of developing colorectal cancer.
Physical Inactivity – People who do not engage in regular physical activity are at increased risk.
Smoking & Alcohol – People who smoke and / or drink alcoholic beverages are at increased risk.
Type 2 diabetes
What decreases my risk?
Any factor that lowers your risk of developing a disease is known as a PROTECTIVE FACTOR. These factors do not guarantee that a disease will not develop. Different cancers have different protective factors. Possible protective factors against colorectal cancer are:
Diet – Evidence suggests that eating a diet containing fruits, vegetables and grains may lower your risk of developing colorectal cancer.
Physical Activity – Exercising on most days of the week may contribute to a reduction in risk.
Additionally avoiding tobacco products and alcoholic beverages may lower your risk.
What are the signs and symptoms?
There are often no signs or symptoms in the early stages. Typical signs and symptoms of colorectal cancer are:
- A change in bowel habits such as diarrhea, constipation, or narrowing of the stool.
- Rectal bleeding, dark stools or blood in your stool.
- A feeling that you need to have a bowel movement that is not relieved by doing so.
- Cramping or abdominal pain.
- Weakness and fatigue
Screening
Screening tests are done on persons who have no signs or symptoms of a disease.
It is recommended that persons of average risk for colorectal cancer begin routine screening at age 50.
Persons considered to be at high risk should begin screening by the age of 40.
There are several tests from which to choose and these can be divided into two groups: tests that may detect colorectal cancer and tests that detect polyps and colorectal cancer.
Tests that may detect cancer
There are three tests, all non-invasive, that can be done in the privacy of your home. All three involve the collection of stool samples. The fecal occult blood test (FOBT) and the fecal immunochemical test (FIT) both look for hidden blood in the stool. However, they may not detect cancer as not all cancers will bleed consistently. These tests can also indicate that cancer may be present when in fact there is no cancer present. It is important if doing the FOBT test that you adhere to dietary and medicine restrictions before and during the test period. Discuss these with your doctor or pharmacist and do not discontinue any regular medication without notifying your doctor.
FOBT or FIT testing should be done annually.
A newer DNA stool test is also available which tests for DNA often found in the fecal matter when colon cancer is present.
If any of these three tests indicate that colorectal cancer may be present, follow-up with a colonoscopy will be required.
Tests that detect polyps and cancer
There are four tests that may detect polyps and cancer and all four require special colonic cleansing prior to having the procedure done. Of these tests, three of them are somewhat invasive.
Double Contrast Barium Enema – Barium liquid is instilled into the large intestine through the anus providing a view of the entire colon through a series of x-rays. If polyps or any suspicious areas are seen follow-up with a colonoscopy will be required. This test should be repeated every five (5) years.
Colonoscopy – A thin flexible tube, with a camera on the end of it is inserted into the rectum and can provide a view of the entire colon. The procedure is done under sedation and precancerous and cancerous growths can be removed and biopsied.
It is recommended that this procedure be done every ten (10) years. This test is considered the “gold standard” in colorectal cancer screening.
Flexible Sigmoidoscopy – Similar to a colonoscopy except that a large portion of the colon is not viewed so some precancerous and cancerous growths may not be seen. It is recommended that this test be done every five (5) years.
Virtual Colonoscopy – This test uses computerized tomographic (CT) technology to view the entire colon and is non-invasive. However, if abnormalities are observed, a conventional colonoscopy will be required.