If you’ve been diagnosed with colon cancer (also known as colorectal cancer), one of the first things your doctor will want to determine is the stage of your cancer.
The stage is used to represent the extent of the cancer and how far it’s spread. Staging colon cancer is essential to determining the best treatment approach.
Colon cancer is typically staged based on the TNM staging system, which was established by the Union for International Cancer Control and later adopted by the American Joint Committee on Cancer.
The system considers the following factors:
- Primary tumor (T). T refers to how large the original tumor is and whether cancer has grown into the wall of the colon or spread to adjacent organs or structures.
- Regional lymph nodes (N). N refers to whether cancer cells have spread to nearby lymph nodes.
- Distant metastases (M). M refers to whether cancer has metastasized (spread) from the colon to other parts of the body, like the lungs or liver.
In some cases, there’s not enough information to assess the tumor or nodes. Instead of including a number (as in T1 or N1), the cancer category will be TX or NX.
Within each of the three categories, the cancer is classified even further and assigned a number and letter to indicate the extent of the disease. These assignments are based on the structure of the colon and how far the cancer has grown through the layers of the colon wall.
The stages of colon cancer are as follows:
This is the earliest stage of colon cancer. In stage 0, the cancer has not grown beyond the mucosa, or the innermost layer of the colon.
In stage 1 colon cancer, the cancer has grown into the innermost layer (or mucosa) to the next layer of the colon (the submucosa). It may have also grown into a muscular layer called the muscularis propria. It has not spread to the lymph nodes.
In stage 2 colon cancer, the disease is a little more advanced than in stage 1 and has grown beyond the mucosa and the submucosa.
Stage 2 colon cancer is classified further as stage 2A, 2B, or 2C.
- Stage 2A. The cancer has not spread to the lymph nodes or nearby tissue. It’s reached the outer layers of the colon, but it has not completely grown through.
- Stage 2B. The cancer has not spread to the lymph nodes, but it’s grown through the outer layer of the colon and to the visceral peritoneum. This is the membrane that holds the abdominal organs in place.
- Stage 2C. The cancer has not spread to the lymph nodes. But it has grown through the outer layer of the colon as well as to nearby organs or structures.
Stage 3 colon cancer is classified as stage 3A, 3B, or 3C.
- Stage 3A. The tumor has grown to or through the muscular layers of the colon and is found in nearby lymph nodes. It has not spread to distant nodes or organs.
- Stage 3B. Colon cancer will be classified as stage 3B in either of the following situations:
- The tumor has grown through the outermost layers of the colon and penetrates the visceral peritoneum or invades other organs or structures. It’s also found in one to three lymph nodes.
- The tumor has not grown through the outermost layers of the colon, but it’s found in four or more nearby lymph nodes.
- Stage 3C. The tumor has grown beyond the muscular layers. Cancer is also found in four or more nearby lymph nodes but not in distant sites.
Stage 4 colon cancer is classified as either stage 4A, 4B, or 4C.
- Stage 4A. This stage indicates that the cancer has spread to one distant site, like the liver, lungs, or lymph nodes.
- Stage 4B. The cancer has spread to two or more distant sites but not to the peritoneum.
- Stage 4C. The cancer has spread to the peritoneum.
Colon cancer is also classified as either low-grade or high-grade.
When a pathologist examines cancer cells under a microscope, they assign a number from 1 to 4 based on how much the cancer cells look like healthy cells. The higher the grade, the more abnormal the cancer cells look.
Low-grade cancers tend to grow slower than high-grade cancers, although this can vary. The life expectancy for people with low-grade colon cancer is also considered to be better.
There are often no signs or symptoms during the early stages of colon cancer. At later stages, symptoms tend to vary based on tumor size and its location in the large intestine.
These symptoms can include:
A doctor can screen for colon cancer by performing one of the tests below:
A colonoscopy is a screening test in which the doctor uses a long, narrow tube with a small camera attached to view the inside of your colon. According to the American College of Physicians (ACP), it’s the standard test for colon cancer.
If for some reason, you’re not a suitable candidate for colonoscopy, the ACP recommends both a FIT and a sigmoidoscopy. The FIT detects blood in the stool. Sigmoidoscopy is similar to a colonoscopy, except the focus is on the final section of the colon (sigmoid colon).
If the results of your FIT or sigmoidoscopy suggest that you have colon cancer, a healthcare professional must then perform a colonoscopy to confirm the diagnosis.
If they find colon cancer, additional tests will often be needed to determine the size of the tumor and whether it’s spread beyond the colon.
There may be instances where the stage of the disease cannot be fully determined until after colon surgery has been performed. After surgery, a pathologist can examine the primary tumor and the removed lymph nodes, which help determine the stage of disease.
The recommended treatment for colon cancer largely depends on the stage of the disease. Keep in mind that treatment will also be determined by the grade of the cancer, your age, and your overall health.
According to the
- Stage 0. Surgery is often the only treatment needed for stage 0 colon cancer.
- Stage 1. Surgery alone is recommended for stage 1 colon cancer. The technique used may vary based on the location and size of the tumor.
- Stage 2. Surgery is recommended to remove the cancerous section of the colon and nearby lymph nodes. Chemotherapy may be recommended in certain circumstances, like if the cancer is considered high-grade or if there are high-risk features.
- Stage 3. Treatment includes surgery to remove the tumor and lymph nodes followed by chemotherapy. In some instances, radiation therapy may also be recommended.
- Stage 4. Treatment may include surgery, chemotherapy, and possibly radiation therapy. In some instances, targeted therapy or immunotherapy may also be recommended.
Below are some questions that people often have about this type of cancer.
Where is the first place colon cancer spreads?
According to the
How fast does colon cancer spread?
Colorectal cancer tends to spread to the liver and lungs 2 years after initial cancer surgery.
- 76 percent were diagnosed with liver metastases within 1 year of their colorectal cancer diagnosis
- 89 percent were diagnosed with liver metastases within 2 years
- 93 percent were diagnosed with liver metastases within 3 years
How the cancer spreads will depend on factors like:
- how early the cancer is found
- how it was treated
- the biology of the cancer
- the aggressiveness of the cell type
- whether there’s a genetic component
- whether there’s a family history of the cancer
Is colon cancer curable at stage 3?
Colon cancer is still curable at stage 3. The standard treatment for this stage is surgery followed by chemotherapy.
Can you live 10 years with stage 4 colon cancer?
Programs in the United States that provide cancer statistics tend to report 5-year survival rates, not 10-year survival rates.
According to the Surveillance, Epidemiology, and End Results (SEER) Program, the 5-year relative survival rate for people with distant colorectal cancer is
Research that looks at survival rates beyond 5 years is lacking.
An older 2012 study from the Netherlands found that the 10-year survival rate for Dutch people with stage 4 colorectal cancer was 7 percent.
A 2019 study from Martinique found that the 10-year survival rate for Martiniquans with all stages of colorectal cancer — not just stage 4 or distant cancer — was 33 percent. This takes into account people diagnosed between 1993 and 2012.
Keep in mind that survival rates continue to improve over time. In addition, early diagnosis of colon cancer is crucial to an improved life expectancy.
The stage of colon cancer will affect your outlook. People diagnosed with stage 1 and 2 colon cancer generally have the highest survival rates.
Remember, the stage of colon cancer is not the only factor that determines survival rate. It’s important to understand that many factors will affect your outlook, including:
- how well you respond to treatment
- your age
- your cancer grade
- your overall health at the time of your diagnosis