Colon cancer is the third most common cancer in the United States. More than 136,000 new cases and 50,000 colon cancer deaths are expected this year. It is estimated that 5% of Americans will get colon cancer during their lifetime. Screening for colon cancer has been among the most successful programs in reducing both the occurrence and death rate of cancer. Although there are other methods to screen for colon cancer, none come close to approaching the success rate of a colonoscopy. A nationwide screening program began in the mid 1980s and was promoted by the U.S. Department of Health and Human Services along with multiple medical organizations. The incidence of colon cancer, which began declining with the commencement of the program,plunged an additional 30% in the last decade among Americans 50 years of age and older, as more people had colonoscopies. The drop in colon cancer related deaths fell about 3% a year between 20 01 and 2010.
Unlike other cancers which develop anywhere in their tissue of origin, colon cancer, with very few uncommon exceptions, begins in colon polyps. Polyps are small growths on the inside wall of the colon which usually give no symptoms. They grow slowly and take several years to reach a size in which they statistically become at risk to turn into cancers. The purpose of colonoscopy is to find and remove these polyps before they have the chance to turn cancerous. The procedure is to prevent the patient from getting cancer, not just to find it at an early stage.
Who is more at risk and who should be screened for colon cancer?
It is recommended that everyone have a screening for colon cancer at age 50 and again at regular intervals. African Americans have a higher risk of colon cancer and some doctors have recommended screening at age 45. For those with risk factors such as a strong family history of colon polyps or colon cancer at an earlier age, screening may start in the 40s. There are some families in which colon cancers are quite frequent and in which a clear genetic source has been identified. These individuals should follow up more frequently. It should be remembered that we are talking only about screening for colon cancer in an asymptomatic individual. If a person has symptoms, such as rectal bleeding, change in bowel habits, unexplained abdominal pain, etc., then a colonoscopy should be done as a diagnostic procedure.
How often should an individual have a colonoscopy?
National standards propose that for asymptomatic people with no additional risk factors, this should be done at 10 year intervals. If a patient had one or more benign polyp(s) removed, then depending on the size and pathology, it should generally be done again in 3-5 years. If a patient had a malignant polyp removed, it should be done sooner. Again, this might vary as per the physical condition and age of the patient. As so many things are in medicine, many variables exist. Every patient is unique. Speak to your primary physician or your gastroenterologist and ask them about whether a screening colonoscopy is indicated for you.