Colorectal cancer is a cancer of the large bowel [colon] or rectum. These cancers are common and deadly; approximately one-third of people who develop it die, making it the second leading cause of cancer death. However, screening tests make it possible to detect existing cancers at an early, treatable stage, before there are any symptoms and prevent the development of colorectal cancer by identifying and removing early growths called adenomatous polyps.
All adults should undergo screening beginning at age 50 or earlier, depending upon a person’s risk of developing colorectal cancer. A history of colon cancer in the family, especially if a parent or sibling increases the risk.
At Ohio GI, we are committed to colorectal cancer prevention. All of our physicians are expert in colonoscopy, the state-of-the-art technique for prevention and detection. We offer colonoscopy in several locations around the Cincinnati area in comfortable (and not embarrassing) centers of excellence. We understand that colonoscopy requires essentially a full day off so for most patients, we do not require an additional pre-colonoscopy visit with us. Via a telephone interview, our staff will make most arrangements, including a specific set of medical questions, to prepare you and us for your colonoscopy visit.
THE IMPORTANCE OF COLORECTAL CANCER SCREENING
Most colorectal cancers develop slowly over many years. They begin as small, benign tumors called adenomatous polyps. These polyps grow, develop precancerous changes, eventually become cancerous, and later spread and become incurable. This progression usually takes about 10 years in most people.
Colon cancer screening tests work by detecting precancerous polyps or cancer while it is still curable. Regular screening for and removal of polyps can very significantly reduce a person’s risk of developing colorectal cancer.
WHO SHOULD BE SCREENED?
Everyone should be screened. Several factors increase an individual’s risk of developing colorectal cancer. Having one or more of these factors will determine the age at which screening should begin, the frequency of screening, and the screening tests that are most appropriate.
RISK FACTORS FOR COLON CANCER
Several characteristics increase the risk of colorectal cancer two to several fold. While each individual risk factor adds some risk, risk is substantially increased if several are present together.
- Family history of colorectal cancer – Having colorectal cancer in a family member increases the risk of getting the cancer, especially if it is a first degree relative (a parent, brother or sister, or child), if several family members are affected, or if the cancers have occurred at an early age (eg, before age 50 years).
- Prior colorectal cancer or polyps — People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps are also at increased risk for developing colorectal cancer.
- Increasing age – Although the average person has a 5 percent lifetime risk of developing colorectal cancer, 90 percent of these cancers occur in people older than 50 years of age. Risk increases with age throughout life.
- Race – African Americans have a higher risk of dying from colorectal cancer than white Americans. This risk is high in native Alaskans and low in American Indians.
- Lifestyle factors – Several lifestyle factors increase the risk of colorectal cancer, including: A diet high in fat and red meat and low in fiber, Eating charred meats, A sedentary lifestyle, Cigarette smoking, Genetic conditions (see below).
- Familial adenomatous polyposis (FAP) is an uncommon inherited condition that increases a person’s risk of colorectal cancer. Nearly 100 percent of people with this condition will develop colorectal cancer during their lifetime, and most of these cancers occur before the age of 50 years. FAP causes hundreds of polyps to develop throughout the colon.
- Hereditary nonpolyposis colon cancer (HNPCC) is another inherited condition associated with an increased risk of colorectal cancer. It is slightly more common than FAP, but is still uncommon, accounting for about 1 in 20 cases of colorectal cancer. About 70 percent of people with HNPCC will experience colorectal cancer by the age of 65. Cancer also tends to occur at younger ages and in the part of the colon on the right side of the body (the ascending colon). HNPCC is suspected in those with a strong family history of colon cancer; several family members from different generations may have been affected, some of whom developed the cancer relatively early in life. Persons with HNPCC are also at risk for other types of cancer, including cancer of the uterus, stomach, bladder, kidney, and ovary.
- Inflammatory Bowel Disease – People with Crohn’s disease of the colon or ulcerative colitis have an increased risk of colorectal cancer. The amount of increased risk depends upon the amount of inflamed colon and the duration of disease. Risk is not increased in people with irritable bowel syndrome.
FACTORS THAT MAY DECREASE THE RISK OF COLON CANCER
- Eat and overall healthy diet that is high in fiber and low in red meat.
- When cooking meat, do not burn or blacken it (charring can create carcinogens)
- Calcium 800-1200mg per day
- Don’t drink more than 2 alcoholic beverages daily
- Don’t smoke
- Get regular exercise and maintain body weight that is not overweight
- Aspirin, ibuprofen, and related nonsteroidal antiinflammatory medications may decrease the risk of developing colorectal cancer but they can also cause problems such as ulcers and bleeding. There is not enough evidence to recommend aspirin or NSAIDs as a preventive treatment for colon cancer
- Antioxidants such as vitamin E, selenium, and beta carotene have not shown risk reduction
- Unfortunately, no special diet or life style modification or supplement can reliably reduce the risk of colon cancer. These measures thus do not replace colonoscopy as the primary and most effective preventative technique.
CURRENT RECOMMENDATIONS FROM THE AMERICAN
COLLEGE OF GASTROENTEROLOGY (ACG):
Preferred CRC Screening Recommendations
- Cancer prevention tests should be offered first. The preferred CRC prevention test is colonoscopy every 10 years, beginning at age 50. Screening should begin at age 45 years in African Americans.
- Cancer detection test. This test should be offered to patients who decline colonoscopy or another cancer prevention test. The preferred cancer detection test is annual FIT for blood.
Alternative CRC Prevention Tests
- Flexible sigmoidoscopy every 5–10 years.
- Computed tomography (CT) colonography every 5 years.
Alternative Cancer Detection Tests
- Annual Hemoccult Sensa.
- Fecal deoxyribonucleic acid (DNA) testing every 3 years.
Recommendations for Screening When Family History is Positive but Evaluation for Hereditary Non-polyposis Colorectal Cancer (HNPCC) Considered Not Indicated
- Single first-degree relative with CRC or advanced adenoma diagnosed at age ≥60 years
Recommended screening: same as average risk.
- Single first-degree with CRC or advanced adenoma diagnosed at age <60 years or two first-degree relatives with CRC or advanced adenomas. Recommended screening: colonoscopy every 5 years beginning at age 40 years or 10 years younger than age at diagnosis of the youngest affected relative.
Familial Adenomatous Polyposis (FAP)
- Patients with classic FAP (>100 adenomas) should be advised to pursue genetic counseling and genetic testing, if they have siblings or children who could potentially benefit from this testing.
- Patients with known FAP or who are at risk of FAP based on family history (and genetic testing has not been performed) should undergo annual flexible sigmoidoscopy or colonoscopy, as appropriate, until such time as colectomy is deemed by physician and patient as the best treatment.
- Patients with retained rectum after subtotal colectomy should undergo flexible sigmoidoscopy every 6–12 months.
- Patients with classic FAP, in whom genetic testing is negative, should undergo genetic testing for bi-allelic MYH mutations. Patients with 10–100 adenomas can be considered for genetic testing for attenuated FAP and if negative, MYH associated polyposis.
Hereditary Non-Polyposis Colorectal Cancer Syndrome (HNPCC)
- Patients who meet the Bethesda criteria should undergo microsatellite instability testing of their tumor or a family member’s tumor and/or tumor immunohistochemical staining for mismatch repair proteins.
- Patients with positive tests can be offered genetic testing. Those with positive genetic testing, or those at risk when genetic testing is unsuccessful in an affected proband, should undergo colonoscopy every 2 years beginning at age 20–25 years, until age 40 years, then annually thereafter.
Cancer Prevention Tests versus Cancer Detection Tests
The recent joint guideline (the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology) groups CRC screening tests into cancer prevention and cancer detection tests. Cancer prevention tests have the potential to image both cancer and polyps, whereas cancer detection tests have low sensitivity for polyps and typically lower sensitivity for cancer compared with that in cancer prevention tests (imaging tests). The ACG supports the division of screening tests into cancer prevention and cancer detection tests, but recommends a preferred cancer prevention test — colonoscopy every 10 years (Grade 1 B) and a preferred cancer detection test — annual fecal immunochemical test (FIT) to detect occult bleeding.