Colorectal Cancer - Diagnosis

Colorectal cancer can be diagnosed by means of a physical examination and a fecal occult blood test. A fecal occult blood test is a test for the presence of blood in stools. The test can be performed very easily by patients themselves. A small sample of stool is placed on a test strip. The test strip is then sent to a laboratory for analysis. The presence of blood in the stool is an indication that colorectal cancer may be present.

Colorectal cancer can also be detected by physical tests. In the simplest test, a doctor inserts a gloved finger up the rectum. The doctor may be able to feel the presence of any abnormal structures in the rectum.

A more advanced test is sigmoidoscopy (pronounced SIG-moi-DOSS-kuh-pee). A sigmoidoscope (pronounced sig-MOI-doe-skope) is a thin, hollow tube that contains a light on one end. The tube is inserted up the patient's rectum into the lower part of the colon. The doctor is able to examine closely the inner walls of the colon and rectum. The presence of any abnormal structures will be apparent.

An even more advanced test is a colonoscopy (pronounced KO-lon-OSS-kuh-pee). A colonoscope (pronounced ko-LON-o-skope) is similar to a sigmoidoscope, but it contains a longer tube and can be inserted farther into the patient's colon. The colonoscope is connected with a video camera and display that allows the doctor to view the inner walls of the colon.

Another test for colorectal cancer is a barium enema. A barium enema consists of a white chalky liquid inserted into the patient's rectum. The liquid flows upward into the colon and coats the walls of the colon and rectum with a white lining that is opaque (dark) to X rays. An X-ray photograph of the colon and rectum is then taken. The photograph shows the detailed structure of the colon and rectum.