Reading time: 7 – 12 minutes
The goal of the annual National Colorectal Cancer Awareness Month is to make people aware of colorectal cancer and to encourage people to learn more about how to reduce their risk of colorectal cancer (CRC) through regular screening and a healthy lifestyle. The results of the National Health Interview Survey (NHIS) administered to 32,374 adults 18 years of age or older in 2000 showed that colorectal cancer screening is underused . Just over 60% of adults had ever had colorectal cancer testing. Only 44% of men and 37% of women greater than 75 years of age were current for testing. Colorectal cancer screening is very important. If colorectal cancer is allowed to metastasize (meaning to spread to other parts of the body), the 5-year survival rate is less than 10%. However, if colorectal cancer is found early, the 5-year survival rate is greater than 90% .
Colorectal cancer can be prevented. Colorectal cancer starts in the digestive system and begins as a polyp. Polyps are small growths of tissue that start in the lining and grow in to the center of the colon or rectum. A specific type of polyp, an adenoma, can become cancerous. Screening for colorectal cancer can identify polyps and they can be removed to prevent cancer from ever occurring. Starting at age 50, men and women who are at average risk for colorectal cancer should get screened. Men and women who have a higher risk of the disease may need to be tested earlier and should talk to their health care professional about when. Colorectal cancer incidence rates are also increasing among people younger that 50 years of age. Indeed, colorectal cancer is ranked among the top 10 cancers occurring in males and females aged 20-49 years regardless of race . No matter what your age, know the risk factors, the symptoms and your family history.
Not counting skin cancers, colorectal cancer is the third most common cancer in the U.S. . However, death due to colorectal cancer is declining. Much of the credit for a decrease in the death rate from colorectal cancer in 2004 has been attributed to screening exams and the early detection of polyps that can be removed before they become cancerous.
The exact cause of most colorectal cancers is unknown. However, there are a number of risk factors.
Age: The chance of having colorectal cancer increases after age 50. However, colorectal cancer incidence rates are increasing among persons younger than 50 years of age .
Prior occurrence of colorectal cancer: The likelihood of having colorectal cancer is increased if you have a previous history of colorectal cancer.
Prior history of polyps: Specific types of polyps increase the risk of colorectal cancer.
History of bowel disease: Ulcerative colitis and Crohn’s disease, diseases that involve inflammation of the colon over a long period of time, increase the risk of colon cancer.
Family history of colorectal cancer: Risk of colorectal cancer is increased if you have relatives that have had this cancer. Twenty percent of individuals diagnosed with colorectal cancer have a first- or second-degree relative with the disease.
Genetic factors: Familial adenomatous polyposis (FAP) is an inherited condition in which numerous polyps form in the large intestine. Malignant transformation occurs 100% of the time if left untreated.
Race: African Americans have the highest rate of colorectal cancer and the highest death rate from colorectal cancer of all racial groups in the United States. The reason for this is not known.
Diet: A diet high in saturated fat can increase the risk of colorectal cancer. Consumption of red meats  and processed meats  can also increase colorectal cancer risk.
Lack of exercise: According to the American Cancer Society (ACS), regular physical activity reduces the risk of colorectal cancer as well as breast and possibly other cancers, and also reduces the risk of cardiovascular disease and diabetes.
Overweight: Being overweight at diagnosis is associated with an increased risk for recurrence of and death from colon cancer .
Smoking: Recent studies suggest that tobacco use, particularly recent use, increases risk for both adenomatous and hyperplastic polyps, precursors of colorectal cancer .
Heavy alcohol use: High alcohol intake is significantly associated with increased risk of colon and rectal cancer .
Diabetes: People with diabetes have an increased risk of colon and rectal cancer .
Many of these risk factors can be avoided by choosing healthy lifestyle alternatives to reduce your risks for developing cancer. Additionally, a number of studies have suggested that folate, beta-carotene, vitamin C and vitamin B6 have a protective effect against colorectal cancer [11-13]. Other studies have suggested protective roles for calcium and vitamin D against colorectal cancer [14-15].
During National Colorectal Awareness Month, experts recommend remembering these important points:
- Colorectal cancer can be prevented.
- Screening for colorectal cancer can identify polyps that can be removed to prevent cancer from ever developing.
- You should begin colorectal cancer screening at age 50 unless you have an increased risk for the disease.
- Colorectal cancer is treatable.
- Know the risk factors, symptoms and your family history of colorectal cancer.
- Talk with your health professional about colorectal cancer and your own risk for the disease.
- Peterson et al. Colorectal Cancer Screening among Men And Women in The United States. J Womens Health (Larchmt). 2007 Jan-Feb;16(1):57-65.
- Dashwood RH. Early detection and prevention of colorectal cancer (review). Oncol Rep. 1999 Mar-Apr;6(2):277-81.
- Fairley et al. Colorectal cancer in U.S. adults younger than 50 years of age, 1998-2001. Cancer. 2006 Sep 1;107(5 Suppl):1153-61.
- Cancer Facts & Figures 2007. Leading Sites of New Cancer Cases and Deaths””2007 Estimates. American Cancer Society. Atlanta, Ga. 2007.
- English et al. Red meat, chicken, and fish consumption and risk of colorectal cancer. Cancer Epidemiol Biomarkers Prev. 2004 Sep;13(9):1509-14.
- Ward et al. Processed meat intake, CYP2A6 activity, and risk of colorectal adenoma. Carcinogenesis. 2007 Feb 2; [Epub ahead of print].
- Dignam et al. Body mass index and outcomes in patients who receive adjuvant chemotherapy for colon cancer. J Natl Cancer Inst. 2006 Nov 15;98(22):1647-54.
- Ji et al. Tobacco smoking and colorectal hyperplastic and adenomatous polyps. Cancer Epidemiol Biomarkers Prev. 2006 May;15(5):897-901.
Moskal et al. Alcohol intake and colorectal cancer risk: a dose-response meta-analysis of published cohort studies. Int J Cancer. 2007 Feb 1;120(3):664-71.
- Larsson et al. Diabetes mellitus and risk of colorectal cancer: a meta-analysis. J Natl Cancer Inst. 2005 Nov 16;97(22):1679-87.
- Kune and Watson. Colorectal cancer protective effects and the dietary micronutrients folate, methionine, vitamins B6, B12, C, E, selenium, and lycopene. Nutr Cancer. 2006;56(1):11-21.
- Senesse et al. Tobacco use and associations of beta-carotene and vitamin intakes with colorectal adenoma risk. J Nutr. 2005 Oct;135(10):2468-72.
- Kato et al. Serum folate, homocysteine and colorectal cancer risk in women: a nested case-control study. Br J Cancer. 1999 Apr;79(11-12):1917-22.
- Gorham et al. Optimal vitamin d status for colorectal cancer prevention a quantitative meta analysis. Am J Prev Med. 2007 Mar;32(3):210-6.
- Park et al. Calcium and Vitamin D Intake and Risk of Colorectal Cancer: The Multiethnic Cohort Study. Am J Epidemiol. 2007 Jan 10; [Epub ahead of print].