Incidence of colon cancer
Colorectal cancer is a characteristic disease in adults who have exceeded the age of 70. However, there are specific types of the disease that are a result of genetic mutations(1) that are transmitted by heredity in families. Therefore, in cases in which there is a family history of colorectal cancer at an age earlier than 60 to 70, it is advisable to undergo tests for early detection of the disease, as elaborated below.
Most tumors are in the terminal part of the colon, meaning that some may be diagnosed by rectal examination (a manual examination of the anus by the physician) or endoscopic study (a test in which a flexible tube and a camera are inserted into the terminal colon)(2).
There are situations in which risk factors that increase the risk of a specific person to suffer from colon cancer may be defined. These risk factors include:
a. Hereditary syndromes(3): genetic diseases that are transmitted by heredity and cause increased risk of tumors in the colon. Usually, these tumors will appear at relatively early age and in some studies a person may suffer from more than one tumor at once.
b. Inflammatory bowel diseases: such as ulcerative colitis and Crohn’s disease. In these diseases, there is a constant inflammatory process in the mucosa of the digestive system, which increases the risk for the onset of malignant tumors of the mucosa of the colon.
c. A person who has had a colon tumor in the past is at increased risk for the development of an additional tumor
d. Certain food types have been found to increase or decrease the degree of risk for colon cancer. For example, it has been found that low fiber nutrition constitutes a risk factor for contracting this disease.
(1)A mutation is a genetic change in tumor cells that cause them to multiply and develop unchecked. There are mutations such as BRCA1 and BRCA2 that are more common in Ashkenazi Jews and therefore constitute a more significant risk factor in the Israeli population. There are a number of ways for testing for / verifying the existence of the mutation. These tests are recommended in cases of a diagnosis of the mutation in a family member or in cases in which there is a greater than usual number of malignant tumors in other relatives. (2)There are a number of endoscopic tests (endo = internal, scopy = inspection):sigmoidoscopy is a study that examines the terminal colon (sigmoid) and may diagnose most tumors. However, today, mostly colonoscopy studies are performed, in which the physician carefully examines all parts of the colon throughout its length. The studies differ in duration and patient discomfort. All studies are performed today with a sedative injection for patients, so that in most cases they pass without any difficulty for the patient. (3)The hereditary syndromes that are known today to increase the risk for colon cancer include, for example, familial polyposis syndrome and Gardener syndrome. Persons affected by these syndromes tend to develop benign tumors (polyps) of the colon mucosa and these tend to become malignant at relatively high frequency. Another syndrome that causes increased risk for colon cancer is a syndrome that does not cause the development of polyps, and accordingly is called hereditary nonpolyposis colon cancer (INPCC).