Diagnosis and Screening for Colorectal Cancer
A typical colon cancer screening exam will start with a full medical history and physical evaluation. This helps your doctor identify possible risk factors. Your doctor will also ask about any symptoms you’ve been having, how serious they are and how long you’ve noticed them.
If you have symptoms of colon cancer or you’ve already had colorectal cancer screening tests that indicate a concern, your healthcare team may suggest additional exams and tests to determine a colon cancer diagnosis.
How is colon cancer diagnosed?
To accurately detect and diagnose colorectal cancer, we use the latest technology:
- CT scan: A computed tomography scan is a tool for detecting colorectal cancer that uses X-rays and dyes in the veins to make pictures of structures inside the body.
- Positron emission tomography scan: The PET scan uses a special camera to see organs in the body. The camera records a tracer (radioactive sugar) that is put into a vein. Cancer cells use more sugar than normal cells, so the tracer shows up in the cancer cells.
These tests help your healthcare team:
- Detect cancer
- Pinpoint its location
- Decide what kind of cancer it is
- Learn how far it has spread (also called staging)
- Develop a treatment plan
With this information, your cancer care team can then determine the best way to treat you.
Screening for colorectal cancer
Experts recommend routine colon cancer testing for everyone age 45 and older who has a normal risk for colon cancer. If you are in a higher risk group, you may need testing sooner. Talk to your doctor about when you should be tested.
Colonoscopy (every 10 years, as recommended by your doctor)
A colonoscopy screening detects changes or abnormalities in the large intestine (colon) and rectum by inserting a long, flexible tube into the rectum.
Computed tomographic colonography (every 5 years, as recommended by your doctor)
CT colonography, or virtual colonoscopy screening. The medical imaging procedure uses X-rays and computers to produce 2- and 3-dimensional images of the colon from the rectum to the lower end of the small intestine.
Flexible sigmoidoscopy (every 5 years, as recommended by your doctor)
The exam evaluates the lower part of the large intestine by inserting a thin, flexible tube into the rectum.
Several types of tests on a sample of your stool can detect signs of colorectal cancer:
- Fecal immunochemical test: FIT tests for hidden blood in the stool, which can be an early sign of cancer. FIT tests should be done yearly.
- Fecal occult blood test: FOBT detects blood in the stool, which may be a sign of colorectal cancer, ulcers or polyps, and should be done yearly.
- Stool DNA test: This test looks for abnormal DNA associated with colon cancer or colon polyps and should be done every 3 years.