The colon and the rectum form part of the digestive system. Colorectal cancer is a term used for cancer that can originate either in the colon or in the rectum. Both have may features in common but might vary in treatment.
The colon is a 6-foot long muscular tube which begins at the end of the small intestine, on the right side of the body called cecum. The rectum and the colon together are called the large intestine. The rectum is 8-inches long and a chamber with forms the lower part of the pelvis that connects the colon to the anus. The colon and rectum together perform the function of processing waste and emptying the bowels. The colon removes water from the stool and the rectum holds the stool for evacuation.
Cancer that starts in the colon is colon cancer. Cancer that starts in the rectum is rectal cancer. And the cancer that affects both or either one of these is called colorectal cancer. When there is abnormal growth of cells or polyps on the inner lining of the colon or the rectum it creates a tumor. This tumor may be termed as cancer. The polyps can be of two types’ intestinal polyps (adenomas) and hyperplastic polyps. Most polyps are harmless but some of them can be cancerous.
Fecal occult blood test: This test checks the presence of blood in feces.
Stool DNA test; This test is done to analyze DNA markers that can be shed into the stool by precancerous polyp cells.
Barium enema x-ray: The contrast dye, barium is placed into the patient’s bowel in the form of an enema. This coats the lining of the bowel and an x-ray is taken. Air is used in a double-contrast barium enema.
Colonoscopy: A long, slender tube with a camera and light at its end is inserted to view the colon and the rectum.
Flexible sigmoidoscopy: A long, flexible tube which is smaller than a colonoscope is inserted into the patient’s rectum and sigmoid. The light and camera at the end of the tube examine the area for polyps which may also be extracted to be examined under the microscope.
CT Colonscopy: This is also called virtual colonoscopy, the machine which takes images of the patient’s colon. The patient’s colon is cleared before the exam for better results.
MRI: This produces three dimensional images of the bowel.
Ultrasound scan: This test uses sound waves to detect the spread of cancer to other parts of the body.
