Biomarkers (Tumor Markers)

In addition to the standard data items found on a pathology report, information on Biomarkers and Genetics can also be found on the pathology report. Some of these may be found on the original pathology report (with or without an addendum), or in a molecular pathology report.

For Colorectal, there are several Biomarker data items. These are called Site-Specific Data Items (SSDIs), and are collected for each case.

See Schemas | SSDI and Grade Data for the SSDI manual and the schema information or SEER*RSA in the Colon and Rectum schema for complete coding instructions for these data items.

Note: For the SSDIs, it is very important that you always read the general instructions (see NAACCR link above) first. For example, the general instructions tell you how to code when there is a range, when “less than” or “greater than” is used. After the general instructions are reviewed, you move to the data specific instructions.

Biomarkers (tumor markers) can be diagnostic, predictive, and/or prognostic.

• Diagnostic: Aid in making diagnosis
• Predictive: Associated with response to treatment
• Prognostic: Associated with disease outcome (i.e., overall survival)

There are several biomarkers that are collected for Colon and Rectum. More information for these SSDIs can be found in the SSDI Manual

Carcinoembryonic Antigen (CEA)

CEA is a nonspecific tumor marker that has prognostic significance for colon and rectal cancers. It is a protein molecular that is found in many different cells of the body. It is commonly used as a marker for gastrointestinal cancer, with colorectal cancer being the most common.

There are other diseases such as biliary obstruction, hepatitis, and heavy smoking can result in an elevated CEA level.

CEA is a frequently used blood test.

An abnormally high CEA is expected to fall after surgical resection. This is due to the tumor burden being removed. An increasing value indicates either an increasing burden (before resection) or a recurrence (after initial treatment).

CEA is collected prior to treatment. Any type of treatment may lower the tumor burden.

There are two SSDIs for CEA

• 3820: CEA Pretreatment Lab Value.
  • Record the actual value in nanograms/millimeter (ng/ml)
• 3819: CEA Pretreatment Interpretation
  • This data item records whether the value is normal, elevated, unknown

Tumor Deposits

Tumor deposits are separate nodules or deposits of malignant cells in perirectal or pericolic fat without evidence of residual lymph node tissue. If present, tumor deposits may be found within the primary lymphatic drainage area of the tumor.

The tumor deposits are different from direct extension from the primary tumor and may be the result of lymphovascular invasion with extravascular extension, a totally replaced lymph node, or discontinuous spread. Nodules of tumor outside the primary lymphatic drainage area of the tumor are distant metastasis.

To evaluate tumor deposits, a surgical resection with a lymph node dissection must be done.

• Do not record information on tumor deposits that is from imaging (MRI) or biopsy

Tumor deposits are associated with regional lymph nodes.

• Record the number of tumor deposits whether or not there are positive lymph nodes.
• If there are positive tumor deposits and negative lymph nodes, code the tumor deposits in the SSDI and the presence of tumor deposits only in EOD regional lymph nodes.
• If there are positive tumor deposits with positive regional lymph nodes, code EOD Regional Nodes based on the positive nodes.
• If there is no surgical resection, code Tumor Deposits to unknown

Perineural Invasion

Perineural invasion is infiltration of nerves around the lesion by tumor cells or spread of tumor along the nerve pathway. The presence of perineural invasion has been shown in several studies to be an indicator of poor patient prognosis. If perineural invasion is not mentioned in the pathology report, do not assume that there is no perineural invasion.

The presence of perineural invasion can be coded from a biopsy or surgical resection; however, to code perineural invasion as negative, a surgical resection must be done.

• If there is no surgical resection, code perineural invasion to unknown

Circumferential Resection Margin

The CRM, also referred to as the radial margin or the mesenteric resection margin, is

• The measurement of the distance from the deepest invasion of the tumor to the margin of resection in the retroperitoneum or mesentery.
• In other words, the CRM is the width of the surgical margin at the deepest part of the tumor in an area of the large intestine or rectum without serosa (non-peritonealized rectum below the peritoneal reflection) or only partly covered by serosa (upper rectum, posterior aspects of ascending and descending colon).

To assess the circumferential resection a surgical resection must be done.

• A polypectomy does NOT qualify as a surgical resection.
• There is a specific code for when a surgical resection is not done.

See the SSDI Circumferential Resection Margin Source Documents (under additional info) for information on other names that are used for circumferential resection margin

Updated: June 24, 2025