Staging is the process of determining if the cancer has grown within the colorectal region or if it has spread to other areas of the body. Information obtained from any screening tests and biopsied tissue samples is used to help determine cancer stage.

There are two staging levels: clinical and pathologic. The clinical stage is based on information obtained before any surgery. This information is obtained from the biopsy, imaging tests and physical exams. The pathologic stage uses the same information found in the clinical stage but adds information discovered as a result of surgery.

Additional tests may also be required to help determine cancer stage. These could include:

  • Blood Tests: Colorectal cancer is often associated with high levels of carcinoembryonic antigen (CEA). A sample of blood may be drawn to test CEA levels. A complete blood count (CBC) test may also be ordered to check for possible anemia caused by prolonged bleeding from the tumor.
  • Chest X-ray: This may be used to see if cancer has possibly spread to the lungs.
    • Colonoscopy: If a colonoscopy was not performed as part of the diagnosis, it will be needed to examine the entire length of colon and help determine the stage of cancer.
  • CT Scan: Dozens of low-dose x-rays are taken all at once from various angles. A CT scan can help see if cancer has spread to the lypmph nodes or other parts of the body.
  • Endorectal Ultrasound: An ultrasound probe is inserted into the rectum. The ultrasound may show how deep a rectal tumor has grown and if the cancer has spread to the lymph nodes.
  • MRI: Magnetic resonance imaging (MRI) produces detailed images of organs and soft tissues, and may pinpoint the exact location and size of a tumor.
  • PET Scan: These scans use more sophisticated techniques to determine if the cancer has spread to other parts of the body that may not be apparent on a CT scan.

Overall Staging


What It Means

Stage 0

Earliest stage of cancer. Tumor has not grown beyond the mucosa. This stage is also known as carcinoma in situ or intramucosal carcinoma.

Stage I

Cancer has grown through the muscularis mucosa into the submucosa or through the submucosa into the muscularis propria. No lymph nodes are involved.

Stage II

Cancer has grown serous membrane, through colon or rectum wall into regional tissue or organs. Lymph nodes and distant tissue and organs are not involved.

Stage III

Ccancer has spread outside the colon to one or more lymph nodes.

Stage IV

Cancer may or may not have grown through the colon and rectal wall. Regional lymph nodes may or may not be involved. Cancer has spread to other distant organs.

Staging in Depth
Detailed information on colorectal cancer staging including TNM categories.

More Information

Risks and Symptoms

Prevention and Screening


Treatment Options