Colorectal cancer is the second leading cause of cancer death in the U.S. and is expected to claim more than 50,000 lives this year. Enhanced screening and treatment have helped to lower colorectal cancer’s overall mortality rate during the past several decades; however, it’s been gradually rising among people under age 55. During Colorectal Cancer Awareness Month, learn what you can do to protect yourself and your loved ones from the potentially devastating effects of colorectal cancer.
The American Cancer Society recommends that adults at average risk of colorectal cancer begin screening at age 45, either with a stool-based test or visual exam. Depending on the test selected, stool-based tests should be repeated every one to three years, and visual exams every five or ten years. Stool-based tests look for blood or a combination of blood and abnormal cell DNA, which may signal the presence of colorectal cancer. If any of these tests come back positive, a colonoscopy will be needed.
Visual exams include colonoscopy, flexible sigmoidoscopy, and CT colonography (also known as “virtual colonoscopy”). During a conventional colonoscopy, a colonoscope is inserted into the rectum and passed through the length of the large intestine. This generally requires IV sedation and carries a small risk of perforating the colon—a complication that can be life threatening. A flexible sigmoidoscopy is similar but reaches less than half of the large intestine. This makes it both more comfortable and less reliable than a colonoscopy. It does not typically require sedation, but this procedure is not widely used in the U.S. today.
A virtual colonoscopy uses CT scanning to create a three-dimensional image of the colon for examination. Rather than sending the colonoscope through the intestine, a small, flexible tube inserted just two inches into the rectum. Carbon dioxide is pumped through this tube to inflate the colon so clear images can be obtained. While this procedure also carries some risk of bowel perforation, it is believed to be a much lower risk than with a conventional colonoscopy. The American College of Radiology (ACR) advises, however, that the risk of perforation is increased during this procedure if the patient is suffering from active Crohn's disease, ulcerative colitis, inflammatory bowel disease or diverticulitis. If you opt for either type of visual exam, be sure to inform your provider of any personal history of these illnesses or previous bowel perforation.
If any screening exam other than a conventional colonoscopy returns positive results, a colonoscopy will have to be performed to identify and remove clinically significant polyps. These will be sent to a lab for biopsy to determine whether precancerous or cancerous changes have occurred.
The following symptoms may indicate colorectal cancer or other illness. Consult your doctor if you notice
Iowa Radiology offers state-of-the-art virtual colonoscopy in the Des Moines area. Contact us for more information, or download our free ebook on CT exams, including CT colonography.