Colon Cancer Stages
The purpose of staging colon cancer is to express how far the disease has progressed. The stages are numbered 0 through IV. The higher the number, the farther the cancer has spread. Colon cancer that has been treated, could not be detected for a period of time, and has returned is referred to as recurrent cancer. The treatment recommended will depend in part on the specific stage the cancer is in.
If a biopsy shows that colon cancer is present, the doctor needs to know the stage of the cancer (how far it has progressed) to plan the best treatment. Colon cancer stages are based on whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body.
Certain tests and procedures may be performed in order to stage colon cancer, including:
- Blood tests
- Chest x-ray
- CT scan
- Lymph node biopsy
The doctor uses blood tests to check for carcinoembryonic antigen (CEA) and other substances in the blood. Some people who have colon cancer or other conditions have a high CEA level.
If a colonoscopy was not performed for diagnosis, the doctor may examine the entire length of the colon and rectum with a colonoscope to check for other abnormal areas.
For this test, an ultrasound probe is inserted into the rectum. The probe sends out sound waves that people cannot hear. The waves bounce off the rectum and nearby tissues, and a computer uses the echoes to create a picture. The picture shows how deep a rectal tumor has grown or whether the cancer has spread to lymph nodes or other nearby tissues.