By Thomas J. McGarrity
Colorectal cancer is the third most common cancer among men and women in the United States. For nonsmokers, colorectal cancer is the No. 1 cause of cancer mortality for both men and women. The chance of being alive or dead five years after a diagnosis of colorectal cancer depends on the stage of the tumor. The stage is determined by how far the tumor has penetrated through the bowel wall and whether the tumor has spread to the lymph nodes or to distant organs. Surgery cures over 90 percent of patients with early stage colorectal cancer. Also, the great majority of colorectal cancers arise from pre-existing polyps. It is estimated that through regular screening and removal of polyps, more than two-thirds of all colorectal cancers could be prevented. Many cancers found through screening are in an early, curable stage.
Colorectal cancer screening is strongly recommended by the American Cancer Society and the United States Services Preventive Task Force as highly effective in reducing the morbidity and mortality associated with colorectal cancer. As more than 90 percent of colorectal cancers are found in patients 50 years and older, routine screening begins at that age. For individuals with a family history of colorectal cancer, earlier screening is recommended. African-Americans have the highest incidence and greater mortality compared to other ethnic groups.
There is a menu of screening options available that have been shown to decrease the death rate due to colorectal cancer. The American College of Gastroenterology recommends colonoscopy every 10 years beginning at age 50 as the preferred colorectal cancer prevention test. Colonoscopy allows for visualization of the entire colon and rectum and any polyps seen can be removed at the same setting. Colonoscopy and other screening types such as sigmoidoscopy and CT colonography requires bowel cleansing, which is distasteful but tolerated by most individuals. Sedation is given during colonoscopy and most find the procedure painless. Colonoscopy and removal of polyps carry a small (less than one percent) chance of bleeding or perforation.
Other less invasive tests to detect colorectal cancer include fecal occult blood test and stool tests looking for abnormal DNA. However, the sensitivity of these noninvasive tests for detecting pre-cancerous polyps and cancers is less than tests that look at the bowel directly.
There are other factors that increase the risk of colorectal cancer. Obesity increases the risk of having and dying from colorectal cancer, whereas, increased physical activity decreases the risk. Smoking, heavy alcohol intake and a high-fat, high red meat diet also are risk factors.
The American public has received good news recently. The incidence and mortality of many cancers, including colorectal cancers, have decreased. Colorectal cancer screening is a highly effective tool to prevent cancer. Please do yourself and family members a favor. Get screened!
Thomas J. McGarrity is chief of the Division of Gastroenterology/Hepatology and professor of medicine in the Department of Medicine at Penn State Milton S. Hershey Medical Center, Penn State College of Medicine.