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Colon Cancer


Colon is the medical term for the large intestine. Colon cancer is the second leading cause of cancer deaths in the United States, second only to lung cancer. In 2005, an estimated 104,950 new cases will be diagnosed, and an estimated 56,290 patients will die of the disease. An individual has about a one in twenty lifetime risk of developing colon cancer. Only about three percent of colon cancers occur in persons under age fourty. Ninty percent of colon cancers occur in patients over age fifty. In the United States, both incidence and mortality rates are declining. This decline may reflect better nutrition and possibly removal of polyps from the colon before they have had a chance to turn into cancer.

Risk Factors

Risk factors for colon cancer are as follows:
Family history of colon cancer.
Familial adenomatous polyposis.
Hereditary nonpolyposis colon cancer.
Having a diet high is animal fat.
Low dietary fiber in the diet.
Having ulcerative colitis or Crohn's disease.
Having three or more alcoholic drinks per day.
Cigarette smoking.
Elevated C-reactive protein that is a blood test.
Well-established risk factors for colon cancer are high dietary fat intake and heredity. Animal fat has the highest association with colon cancer. About 15 percent of all colon cancer patients have a family history of colon cancer in a first-degree relative. Low dietary fiber is also associated with a higher risk of colon cancer. Fiber seems to dilute the cancer-causing substances (carcinogens) in the stool and therefore the bowel wall has less exposure to the carcinogens. A sedentary lifestyle and obesity are both correlated with an increased risk of colon cancer. Interestingly, removal of the gallbladder is associated with a small increase in colon cancer in females. Excessive alcohol intake has also been associated with an increased risk of colon cancer.

Reducing your risk

Diets that are high in fruits and vegetables are associated with a lower colon cancer risk.
Regular physical exercise decreases your chance of getting colon cancer by 50 %.
Increasing dietary fiber in your diet.
Reducing your intake of animal fat may reduce your risk of colon cancer.
Taking aspirin or other anti-inflammatory (like ibuprofen) medication daily.
Taking folic acid daily.
Increasing dietary calcium intake.
Statins seem to have a protective effect.
Estrogen replacement therapy lowers the risk of colon cancer.

Dietary fat should constitute less than 30 percent of total caloric intake. Dietary fiber should exceed 20 grams each day. Your diet should be rich in vegetables and fruits. Alcohol consumption should be no more than two drinks per day for males and one drink a day for females. Exercise has been shown to reduce the risk of colon cancer by 50 percent. Taking an aspirin as few as three times a week has been shown to reduce the incidence of colon cancer by 30 percent. Increasing the amount of vitamin D and calcium in the diet may reduce your risk of developing colon cancer. Taking a multivitamin everyday would provide folic acid.

Symptoms of Colon Cancer

Colon cancer may be present for years before any symptoms develop. This is because colon cancer develops over several stages. Polyps develop first and slowly turn into a cancerous growth. This progression of events usually takes around 7-10 years. This makes colon cancer amenable to being diagnosed at an early stage when it is preventable (removing polyps) or completely curable. Symptoms of colon cancer are:

Rectal bleeding.
Change in bowel habit.
Abdominal pain.
Unexplained anemia.
Rectal bleeding requires an evaluation by your physician. Don't assume that the blood is from hemorrhoids. Many patients that I diagnose with colon cancer have a history of rectal bleeding. They assumed the rectal bleeding was due to their hemorrhoids and delayed seeking treatment.

Screening for Colon Cancer

Several options are available for colon cancer screening:
Annual fecal occult blood test (FOBT). This is commonly referred to as stool cards.
Sigmoidoscopy exam every five years beginning at age 50 along with annual stool cards.
Colonoscopy exam every ten years beginning at age 50 along with annual stools cards.
Barium enema every five years. This method of screening has lost favor over the past decade.
A sigmoidoscopy consists of inserting a fiber optic tube into the rectum and directly examining the bowel wall. It is about 2 feet long and doesn't require sedation. The colonoscopy consists of a 7 foot fiber optic tube that allows visualizing the entire colon. A colonoscopy is preferred if you have a family history of colon cancer or if you have rectal bleeding. The FOBT should be done yearly beginning at age 50 even if a colonoscopy is performed. FOBT can detect colon cancers that may have been missed by the colonoscopy. The colonoscopy is quite good at detecting polyps and colon cancer but it is not perfect. The colon is tortuous and has numerous folds that can hide a polyp or cancer from even the most experienced gastroenterologist. Screening should begin earlier if there are any significant risk factors for colon cancer. Studies have shown that a yearly fecal occult blood test by itself can actually reduce the death rate from colon cancer by 33 percent. Having a sigmoidoscopy every five years along with yearly stool cards will reduce your chances of dying of colon cancer by around 70%. Having a colonoscopy every ten years has not been proven to reduce the death rate but most physicians feel it will reduce the death rate significantly greater than 70%. Colonoscopies are associated with a higher complication rate than sigmoidoscopies. If a first-degree relative has had colon cancer, then screening should begin at age 35 or 10 years younger than the age the relative was first diagnosed. A digital rectal exam should be performed every year beginning at age 50 for all males and females.


If the cancer is confined to a polyp, then the chances of cure are extremely good. Radiation therapy is also used to treat colon cancer. Chemotherapy has been shown to reduce recurrences and improve survival. The five year survival is rate is 61 % in the United States according to the National Cancer Institute.


Pedersen, TR, Berg, K, Cook, TJ, et al. Safety and tolerability of cholesterol lowering with simvastatin during 5 years in the Scandinavian Simvastatin Survival Study. Arch Intern Med 1996; 156:2085.
Grau, MV, Baron, JA, Sandler, RS, et al. Vitamin D, calcium supplementation, and colorectal adenomas: results of a randomized trial. J Natl Cancer Inst 2003; 95:1765.
Wu, K, Willett, WC, Fuchs, CS, et al. Calcium intake and risk of colon cancer in women and men. J Natl Cancer Inst 2002; 94:437.
Erlinger, Tp, Platz, EA, Rifai, N, Helzlsouer, KJ. C-reactive protein and the risk of incident colorectal cancer. JAMA 2004; 291:585.
Colangelo, LA, Gapstur, SM, Gann, PH, Dyer, AR. Cigarette smoking and colorectal carcinoma mortality in a cohort with long-term follow-up. Cancer 2004; 100:288.
Nilsen, TI, Vatten, LJ. Prospective study of colorectal cancer risk and physical activity, diabetes, blood glucose and BMI: Exploring the hyperinsulinaemia hypothesis. Br J Cancer 2001; 84:417.
La Vecchia, C, Negri, E, Decarli, A, Franceschi, S. Diabetes mellitus and colorectal cancer risk. Cancer Epidemiol Biomarkers Prev 1997; 6:1007.
Parkin, DM, Pisani, P, Ferlay, J. Globa; Cancer statistics. CA Cancer J Clin 1999; 49:33.
Giovannucci E, Rimm E, et al. Aspirin Use and the Risk for Colorectal Cancer and Adenoma in Male Health Professionals. Annals of Internal Medicine 1994 Aug. 15; p 241-46.
Mandel j, et al. Reducing Mortality from Colorectal Cancer by Screening for Fecal Occult Blood. N Engl J Med 1993 328:1365-1371.
Decosse J, et al. Cancer Statistics, 1994. Vol 44 No. 1: 27-40.
Jemal, A, et al. Cancer statistics, 2005. CA Cancer J Clin 2005; 55:10-30.


The information provided above is offered as a community service about health-care issues and is not a substitute for individual consultation. Advice on individual problems should be obtained from your personal physician. This information is based on research by the author and represents his interpretation of the literature.

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Readers may send questions to our email address. This column is for informational purposes only and is not a substitute for professional or medical advice.

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