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Contents
  • The TNM Staging System
  • Imaging Tests for Staging
  • Surgical Staging
  • Blood Tests and Biomarkers

Staging Colorectal Cancer: How Doctors Determine the Extent of the Disease

Staging Colorectal Cancer: How Doctors Determine the Extent of the Disease

Mapping the Cancer

When colorectal cancer is diagnosed, determining its stage is crucial for planning treatment and estimating prognosis. Staging involves a series of tests and procedures to assess how far the cancer has spread.
Contents
  • The TNM Staging System
  • Imaging Tests for Staging
  • Surgical Staging
  • Blood Tests and Biomarkers

The TNM Staging System

Doctors use the TNM system to stage colorectal cancer. T describes the size of the tumor and how deeply it has grown into the bowel wall. N indicates whether cancer has spread to nearby lymph nodes. M shows if the cancer has metastasized to other parts of the body. These factors are combined to determine the overall stage, ranging from 0 (very early) to IV (advanced).

Imaging Tests for Staging

Several imaging tests help determine the cancer's stage. CT scans of the chest, abdomen, and pelvis can show if the cancer has spread to nearby organs or distant sites. For rectal cancer, MRI provides detailed images of the rectum and surrounding tissues. PET scans may be used to look for cancer spread throughout the body, especially if other tests are unclear.
Staging of colorectal cancer involves determining the size and spread of the cancer using the TNM system and imaging tests.

Surgical Staging

The most accurate staging often occurs during surgery to remove the cancer. The surgeon can directly observe the extent of the tumor and nearby spread. Lymph nodes are removed and examined under a microscope to check for cancer cells. In some cases, laparoscopy (a minimally invasive procedure) might be done before major surgery to check for small areas of cancer spread.

Blood Tests and Biomarkers

Blood tests can provide additional information for staging. Liver function tests may indicate if cancer has spread to the liver. The tumor marker CEA (carcinoembryonic antigen) can be elevated in some colorectal cancers and may help monitor treatment response. However, CEA isn't specific to colorectal cancer and isn't used alone for diagnosis or staging.

FAQs

How long does staging take?

It can take several days to weeks to complete all necessary tests.

Can stage change over time?

Yes, cancer can progress to a higher stage if it grows or spreads.

Is a biopsy always needed for staging?

Usually yes, to confirm cancer and examine its characteristics.

How accurate is cancer staging?

It's generally quite accurate but not perfect.

Does stage always determine treatment?

Stage is crucial but other factors also influence treatment decisions.

A Critical Step

Accurate staging of colorectal cancer is a complex but essential process that guides treatment decisions and helps predict outcomes for patients.
Have questions about colorectal cancer staging? Consult with Doctronic to understand what your stage means for your treatment options.
Additional References
  1. American Cancer Society. Colorectal Cancer Stages. cancer.org
  2. National Cancer Institute. Colorectal Cancer Treatment (PDQ®)–Health Professional Version. cancer.gov
  3. American Joint Committee on Cancer. AJCC Cancer Staging Manual, 8th Edition. cancerstaging.org
This article has been reviewed for accuracy by one of the licensed medical doctors working for Doctronic.